IEEE Transactions on Biomedical Engineering
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An MR-Safe Endovascular Robotic Platform: Design, Control, and Ex-Vivo Evaluation
Endovascular interventions in combination with fluoroscopic navigation are a standard of care for diagnosis and treatment of cardiovascular diseases. Our work focuses on novel robotic systems for use in non-ionising MRI environments and enhanced manipulation of endovascular instrumentation. We present a novel robotic platform that comprises of a remotely operated MR compatible manipulator and an intuitive user interface. We evaluate the device performance in an expert user study with manual vs. robotic execution of endovascular tasks in ex-vivo phantoms. The promising study results may promote a paradigm shift towards fusion of robotic endovascular surgery with MRI-based navigation... Read more
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Multi-Angular Electroretinography (maERG): Topographic mapping of the retinal function combining real and virtual electrodes
This work aims to create a functional retinal map, to locate potential areas of diseased retina. To do so, we created a new electroretinogram recording method which increases the number of recording electrodes around the eye from only a few real ones, by simply moving the gaze. We show that, by solving the inverse problem with an eye model, we can recreate the retinal activity that would have produced the many signals obtained. We present the best recording method and requirements needed for our novel technique to reliably reproduce the retina’s topographic activity, which should improve disease detection and follow-up... Read more
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Bio-inspired Haptic Feedback for Artificial Palpation in Robotic Surgery
This study tests whether an algorithm that simulates the responses peripheral touch receptors improves performance compared to standard algorithms in a tumor detection task, tested using a combination of vibration and force feedback with a da Vinci surgical robot. The novel bio-inspired algorithm was the only one that allowed both novices and expert robot-assisted surgeons to easily identify the locations of hard, medium and soft tumors and did so with reduced contact force and tumor contact time. Although tested with only a single sensor and actuator of each class, it can easily scale up for greater coverage and sensitivity... Read more
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Computer Assisted Planning for Curved Laser Interstitial Thermal Therapy
We present a detailed retrospective study on clinical epilepsy patient data, showing the potential advantage of following a curved path in the brain for both insertion and ablation purposes. Curved trajectories that follow the contours of given anatomy, as the amygdala-hippocampal complex (AHC) in the case of refractory epilepsy, were associated with a statistically significant improvement compared to their straight counterpart. Benefits were measured in terms of several quantitative metrics including percentage coverage of the ablation region and a published risk score to quantify, among other aspects, the safe distance between the ablation trajectory and critical brain regions... Read more
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Mechanical Imaging of Soft Tissues with Miniature Climbing robots
We propose a method that uses our previously developed skin-crawling robots to noninvasively test the mechanical properties of soft tissue. We explore the use of two miniature sensors: an indenter and a cutometer. We evaluate the sensor's performance from data collected on simulated tissue, classifying the depth and size of a simulated lump with over 98.8% accuracy using convolutional neural nets. Finally, we do limited on-body testing to map dry skin on the forearm with a cutometer. We hope to improve the ability to test tissues noninvasively, providing better sensitivity and systematic data collection... Read more
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Towards Non-invasive Lung Tumor Tracking Based on Patient Specific Model of Respiratory System
This work aims to calculate a complex internal respiratory and tumoral movements by measuring respiratory airflows and thorax movements. We present a new lung tumor tracking approach based on a patient-specific biomechanical model of the respiratory system, which takes into account the physiology of respiratory motion to simulate the real non-reproducible motion. We have evaluated the model accuracy on five public datasets and over all phases of respiration. The results demonstrate the effectiveness of our physics-based model. This model can be potentially used as non-invasive lung tumor tracking system during treatment based on external sensors... Read more
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Design and Preliminary Performance Assessment of a Wearable Tremor Suppression Glove
Approximately 25% of individuals living with parkinsonian tremor do not respond to traditional treatments. This study presents a novel wearable tremor suppression device (WTSD) that can suppress tremor simultaneously, but independently, in the index finger, thumb, and wrist without restricting the user’s voluntary motion. The prototype was tested and assessed on a participant living with parkinsonian tremor, demonstrating the feasibility of using a WTSD to manage hand and finger tremor. The device enriches the field of upper-limb tremor management, as the first WTSD for multiple joints of the hand... Read more
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In-The-Wild Interference Characterization and Modelling for Electro-Quasistatic-HBC with Miniaturized Wearables
Electro Quasi-Static Human Body Communication (EQS-HBC) is an emerging communication technique that utilizes the conductive medium of the human body to achieve enhanced energy efficient and physically secure communication in comparison to traditional radio wave-based technologies like Bluetooth. This work presents 1) a thorough characterization of interference on the human body in day-to-day life and 2) develops a human body interference coupling biophysical model. The measurements provided in this paper can serve as a guide for device designs or future EQS-HBC studies as it provides understanding into coupling modalities of interference and accurate interference measurement techniques... Read more
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Electroosmosis Based Novel Treatment Approach for Cerebral Edema
This work aims to develop a novel treatment approach for cerebral edema. We propose electroosmosis based treatment to drive edematous fluid out of the brain parenchyma by direct current based on the brain tissue’s electroosmotic property. The predicted results demonstrate that the edematous fluid can be driven out of edema region to subarachnoid space and then absorbed into the superior sagittal sinus together with cerebrospinal fluid to achieve the alleviation of the cerebral edema. The proposed approach has the potential to be developed as a new treatment solely or as a complement to existing conventional treatments of edema... Read more
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Pulse Arrival Time Segmentation into Cardiac and Vascular Intervals – Implications for Pulse Wave Velocity and Blood Pressure Estimation
Pulse wave velocity (PWV) is a pressure-dependent marker of arterial stiffness, wherefore pulse arrival time (PAT) has been widely investigated for cuff-less blood pressure (BP) estimation. However, PAT is typically biased by a cardiac delay and peripheral vasculature. Therefore, we demonstrate an ultrasound-based method for central PAT segmentation into cardiac isovolumic contraction (IVC) and vascular pulse transit time (PTT). Contrasting peripheral PAT, central PTT-based PWV explained more than twice as much variability in the reference PWV and yielded significantly lower BP estimation errors. Thereby this unilateral arterial stiffness assessment bears the potential to improve cardiovascular risk assessment in clinical routines... Read more
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Quantitative Evaluation of the Thickness of the Available Manipulation Volume Inside the Knee Joint Capsule for Minimally Invasive Robotic Unicondylar Knee Arthroplasty
The development of novel robotic surgical instruments such as a laser-cutting tool for minimally invasive unicompartmental knee arthroplasty (UKA) is challenging when quantitative requirements are missing. Therefore, we developed and applied a method to quantify the volume inside the knee joint available to manipulate robotic surgical instruments during minimally invasive procedures. We 1) injected contrast solution into nine cadaveric knees, 2) performed and segmented computed tomography scans, and 3) investigated the size and distribution of the injected contrast solution’s volume inside the knee joints. The injected contrast solution’s volume represented the available manipulation space for minimally invasive surgical instruments... Read more
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Contrast-free detection of focused ultrasound-induced blood-brain barrier opening using diffusion tensor imaging
Karakatsani et al. report a contrast-free method to detect focused ultrasound (FUS)-induced blood-brain barrier (BBB) opening using diffusion tensor imaging (DTI). The localized BBB opening was hypothesized to result to a transient change in the diffusion pattern of water molecules and was tested in a non-human primate model, which closely resembled the human anatomy. They found that fractional anisotropy within the targeted area increased by 82% after the procedure, showing that DTI can confirm BBB opening without the use of contrast agents, increasing the safety of the methodology since contrast does not have to cross into the brain parenchyma... Read more
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Guide-wired Helical Microrobot for Percutaneous Revascularization in Chronic Total Occlusion in-vivo Validation
Here we show an enhanced powered guide wired helical millirobot for mechanical thrombectomy in cardiovascular intervention capable of autonomous therapeutics. We build up and demonstrate a millimeter robot fabrication with a spherical joint and a guidewire, a high-power and frequency actuation via external electromagnetic field control, and autonomous therapeutic motions comprise driving, steering, and drilling. We validate all performances in two-dimensional fluidic channels mimicking the vascular network and finally in-vivo environments. Beyond nature-inspired millirobot technologies, our work has the potential of advanced mechanical thrombectomy application and advancement of micrometer and millimeter robot technology toward real clinical utilization... Read more
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Living Donor-Recipient Pair Matching for Liver Transplant via Ternary Tree Representation with Cascade Incremental Learning
This work visually analyzes anatomical variants of liver vessels anatomy to maximize similarity for finding suitable living donor-recipient pairs. We leverage incremental learning in a cascade feature mapping way via updating input CTA training model to optimize segmentation capability. A ternary-tree-based approach is proposed to map all possible liver vessel variants into their respective tree topologies. The ternary tree in-order traversing is designed to efficiently compare the digital strings of two anatomically varied vessel structures to find a suitable match. Experiments through visual illustrations and quantitative analysis demonstrated our method computed very efficiently for finer visualization of liver tree structures... Read more
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Ultra-high-resolution 3D optical coherence tomography reveals inner structures of human placenta-derived trophoblast organoids
Many pregnancy complications are assumed to have their pathophysiological roots in early stages of placentation. Hence, trophoblast research represents a pre-requisite to help preventing pregnancy disorders that endangers uncomplicated gestations and jeopardizes maternal/fetal wellbeing later in life. Recently established 3D trophoblast organoids (TB-ORG) advanced human placental research. However, gold standard methods for determining TB-ORG architectures lack imaging depth and/or are endpoint analyses. We addressed these problems with 3D optical coherence tomography (OCT). This work demonstrates for the first time that OCT resolves label-free inner structures of TB-ORG during cultivation and enables qualitative/quantitative assessment of their differentiation status without sample destruction... Read more
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A Preclinical System Prototype for Focused Microwave Breast Hyperthermia Guided by Compressive Thermoacoustic Tomography
Focused microwave breast hyperthermia (FMBH) can provide accurate and cost-effective treatment of breast tumors with low side effect. A clinically feasible FMBH system requires a guidance technique to monitor the microwave power distribution in the breast. Compressive thermoacoustic tomography (CTT) is a suitable guidance approach for FMBH. We developed a preclinical system prototype for the FMBH-CTT technique, mainly containing a microwave phased antenna array and an ultrasound transducer array. Experimental results demonstrate that the CTT technique can offer reliable guidance for the entire process of FMBH, i.e., from unfocused to focused microwave power distribution... Read more
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A Robotically Steerable Guidewire with Forward-Viewing Ultrasound: Development of Technology for Minimally-Invasive Imaging
Inability to visualize or cross chronic total occlusions leads to high failure rates (25%) during endovascular treatment of peripheral artery disease. To address this problem, a robotically-steerable guidewire system (0.035’’-diameter) was developed with integrated forward-viewing ultrasound guidance. A custom, sub-millimeter ultrasound transducer and a synthetic aperture image formation approach were developed, allowing imaging with high resolution (0.25 mm) and sensitivity (SNR = 31 dB). Imaging performance was demonstrated in phantoms and an ex vivo artery. This robotically-steered guidewire with forward-viewing guidance can increase procedural success by navigating across chronic total occlusions that cannot currently be crossed in endovascular procedures... Read more
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Selective activation of cortical columns using multichannel magnetic stimulation with a bent flat microwire array
This work presents a novel bent flat microwire array for multichannel intracortical magnetic stimulation and demonstrates its effectiveness for selective activation of cortical columns. Computational modeling and physiological experiments revealed that bent wire array can selectively activate different cortical columns simultaneously, and that both the spatial extent of activation and the spatial resolution are influenced by the spacing between the bent wires as well as the stimulus intensity. These results suggest that bent microwire arrays can enhance the selectivity of multichannel stimulation of cortex and therefore may help to develop reliable and effective cortical neural prostheses... Read more
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An Instrumented Cochlea Model for the Evaluation of Cochlear Implant Electrical Stimulus Spread
A 3D-printed physical cochlea model with integrated sensing wires is presented, to evaluate the stimulation current spread of a cochlear implant (CI) in a cochlea. These wires are independent from the stimulating electrodes of a CI. Therefore, the measured current spread signals are not influenced by electrode-electrolyte interface potential near the CI, which is an important issue for conventional measurements that causes missing information in current spread distribution in a cochlea. This physical cochlea model provides an objective platform for comparing different CIs, as well as different stimulation modes and configurations, thus potentially offering optimized setup for specific CI patients... Read more
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Automated Embryo Manipulation and Rotation via Robotic nDEP-tweezers
Embryo manipulation is a fundamental task in assisted reproductive technology (ART). This work presents a robotic negative Dielectrophoresis (nDEP)-tweezers that can enable embryo translation and orientation easily. An inverted microchip with quadrupole electrodes is attached to a micromanipulator to become a robotic DEP tweezers, and a motorized platform provides additional mobility to the embryos lying on a Petri dish. Vision-based algorithms are developed to evaluate relevant information of the embryos from the image, and to provide feedback signals for precise position and orientation control of the embryo. This system offers a non-contact, low-cost, flexible, and effective method for high-precision embryo manipulation... Read more
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Continuous estimation of acute changes in preload using epicardially attached accelerometers
Changes in left ventricular preload can be measured by an accelerometer attached to the epicardium by assessing the changes in the first heart sound frequency. As end-diastolic volume and myocardial stiffness increases, the frequency of the myocardial vibrations associated with the first heart sound also increases and vice versa. We tested this hypothesis in an animal model with changing volume status and found that these novel accelerometer-based measurements were comparable to the current clinical standard methods, both to estimate preload and in identifying fluid responsiveness, i.e. a positive response to fluid administration... Read more
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Transcranial Focused Ultrasound Neuromodulation of Voluntary Movement-related Cortical Activity in Humans
Low-intensity transcranial focused ultrasound (tFUS) is a non-invasive brain stimulation tool for reversibly modulating brain circuits. How the tFUS influences the human voluntary motor processing in the brain remains unclear. We applied the tFUS to modulate the movement-related cortical potential (MRCP) originating from human subjects practicing a voluntary foot tapping task. The MRCP source was reconstructed and evaluated for assessing the tFUS neuromodulatory effects on the voluntary MRCP. The effect of ultrasound pulse repetition frequency was further assessed in modulating the MRCP. This work provides the first evidence of tFUS enhancing the human endogenous motor cortical activities through excitatory modulation... Read more
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Portable Automatic Micro-Ring Resonator System Using a Subwavelength Grating Metamaterial Waveguide for High-Sensitivity Real-Time Optical-Biosensing Applications
As the needs for bio-related detections continue to intensify in the healthcare industry due to the COVID-19 pandemic, our work on Si-microring slow-light systems comes as a timely aide with its small size, fast screening, and early diagnosis capabilities. The presented portable system integrates Si photonics with automated mechanical configurations in a platform that provides faster and real-time readouts, higher sensitivities, all working within the optical telecommunication bands, and ready for portable remote area point-of-care applications. With different receptors immobilized on the chip surface, it is also good for open applications in heavy metal detection, virus examination, and cancer diagnosis... Read more
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Design and Preliminary Assessment of a Passive Elastic Leg Exoskeleton for Resistive Gait Rehabilitation
While devices that assist walking can enable individuals with neuromusculoskeletal impairments, recovery is often better facilitated by devices that resist walking. Moreover, current robotic interfaces for gait rehabilitation are typically huge, bulky, and come with a large price tag. This article describes the design and development of a novel, wearable, passive elastic exoskeleton for resistive gait rehabilitation. The system uses counteracting compressional springs, pulleys, and clutches and can be configured to resist flexion, extension, or bidirectionally. Thus, the device can target user-specific muscle weaknesses and accommodate range of motion limitations. These concepts were validated using benchtop and human subject experiments... Read more
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Modeling of Interstitial Ultrasound Ablation for Continuous Applicator Rotation with MR Validation
Predictive modeling can play an important role in thermal ablative cancer treatments where estimated energy deposition may integrate into pre-operative planning software or combine with closed loop control. In this work, we develop a finite element model capable of simulating continuous rotation by a directional interstitial ultrasound applicator. The developed model simulates temperature maps for different rotation trajectories. The developed simulation was validated using magnetic resonance thermal imaging and demonstrated performance suitable for real-time control of robotically actuated conformal tumor ablation... Read more
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Hybrid Tongue – Myoelectric Control Improves Functional Use of a Robotic Hand Prosthesis
To achieve increased clinical impact with myoelectric upper limb prostheses, control schemes need to effectively perform different grasping actions and simple manipulation tasks enabling the execution of Activities of Daily Living (ADL). In this comparative study we demonstrate, that a control scheme allowing for direct activation of grasps using a tongue interface, and proportional control of opening and closing using two EMG signals, can be an attractive method for providing enhanced control of multifunctional prosthetic hands. This was shown using functional evaluation focusing on the completion of ADL tasks characterised by bimanual activities, which are particularly challenging for prostheses users... Read more
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Flexible, Air Dryable, and Fiber Modified Aerogel-Based Wet Electrode for Electrophysiological Monitoring
This study presents a novel type of wet electrode material for electrophysiological monitoring based on a conductive aerogel film. The electrode material incorporates cellulose nanocrystal and fiber as a biocompatible polymer and multi-walled carbon nanotube as a conductive filler. The wet aerogel film presents suitable mechanical flexibility and a high water absorption due to the porosity of the film and hydrophilicity of the base polymer allowing it for effective wet electrode applications. The electrical impedance range of the fabricated aerogel electrodes is within the range of use for various electrophysiological monitoring purposes such as electrocardiography (ECG) and electroencephalography (EEG)... Read more
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Development and Characterization of a Non-Thermal Plasma Source for Therapeutic Treatments
A non−thermal plasma (NTP) system constituted by a radiofrequency generator directly coupled to a treatment probe is described. The NTP generated was analyzed and characterized to determine a plasma safety profile and a spreading technique to be used on heat−sensitive matter. When NTP interacts with surrounding air particles produces reactive oxygen and nitrogen species that exhibit bactericidal and antiseptic effects due to their strong biochemical reactivity. Afterward, the NTP source was validated through bacterial deactivation trials, biological tests and promoting and in vivo wound closure performed in mice. NTP source demonstrated faster wound healing than that performed with conventional treatments... Read more
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Rapid impedance spectroscopy for monitoring tissue impedance, temperature, and treatment outcome during electroporation-based therapies
Electroporation-based therapies (EBT) employ high voltage pulsed electric fields to permeabilize tumor tissue; this results in a detectable impedance change. Impedance characterization with a potentiostat is limited by acquisition time (~10s) as this timeframe is larger than pulse periods used with EBTs (~1s). Here, we develop a rapid electrical impedance spectroscopy (EIS) method for impedance characterization (<1s) of electroporation and thermal effects during irreversible electroporation. A biphasic rectangular chirp signal allows for impedance measurements between 1.8 kHz – 4.93 MHz. For the first time, we show impedance analysis at high frequencies (~1 MHz) can delineate thermal effects from electroporation effects... Read more
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Fast EEG-based decoding of the directional focus of auditory attention using common spatial patterns
Current hearing devices lack information about the sound source a user attends to when there are multiple speakers. Auditory attention decoding (AAD) algorithms, which decode the auditory attention from brain signals, solve this problem and inform the hearing device about the to-be-enhanced speaker. While current AAD algorithms typically require an EEG buffer of 10s, leading to long delays, we present a new fast and accurate AAD algorithm that decodes the spatial focus of auditory attention in 1s using common spatial pattern filtering... Read more
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Distortion of the Intracranial Pressure Waveform by Extraventricular Drainage System
The EVD-based pressure measurement occurs at the distal end of fluid filled elastic tubing that may itself act as a filter and distort the waveform. While the frequency response of arterial catheter systems has been studied extensively to understand their transfer function characteristics for detailed waveform analysis of the arterial blood pressure wavelet, the degree to which the EVD and associated drainage system distort the ICP waveform has not been investigated systematically, yet... Read more
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Learning Multiparametric Biomarkers for Assessing MR-Guided Focused Ultrasound Treatment of Malignant Tumors
A significant challenge for noninvasive MR-guided focused ultrasound (MRgFUS) treatment is assessing the viability of treated tissue during and immediately after MRgFUS procedures. Current clinical assessment uses contrast agents that prevent continuing MRgFUS treatment if tumor coverage is inadequate. This work presents a novel, noncontrast, learned multiparametric MR biomarker that can be used during treatment for iterative assessment with inhibiting treatment continuation. Trained using a novel volume-conserving registration algorithm, the presented noncontrast biomarker outperformed the current clinical standard on a VX2 rabbit tumor model. Details on the registration and deep learning model are included... Read more
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Teleoperation of an ankle-foot prosthesis with a wrist exoskeleton
This work aims to mimic sensorimotor control pathways disrupted after amputation with a system that allows a user to teleoperate their ankle-foot prosthesis with a wrist exoskeleton while receiving augmented sensory feedback. We present a novel wrist exoskeleton design and two control strategies that dictate ankle prosthesis behavior based on wrist input. We validate all system components with benchtop testing and demonstrate that one individual with transtibial amputation can accurately command desired wrist trajectories while walking. Systems like this have the potential to provide insight into human motor control and improve functional gait metrics for people with lower-limb amputation... Read more
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Performance Evaluation of a Wearable Tattoo Electrode Suitable for High-Resolution Surface Electromyogram Recording
Commercial high-density surface electromyography (HDsEMG) electrodes have limited spatial fidelity, and require electrode paste. As a result, the recorded signals have limited sharpness, inadequate spatial density, and are prone to movement artifacts during muscle contraction. We here demonstrate a novel TATTOO electrode, a dry HDsEMG electrode with a programmable layout. The tattoo electrode is built on stretchable electronics and offers superior skin conformity that can guarantee recording of high-quality HDsEMG signal. We routinely record a larger signal amplitude with higher signal power and occupied bandwidth compared to commercial electrodes. This will potentially enable high-quality recording in clinical applications... Read more
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ValveTech: a Novel Robotic Approach for Minimally Invasive Aortic Valve Replacement
The presented surgical robot (called ValveTech) provides a highly controllable instrument for efficient delivery of an artificial valve under integrated endoscopic vision. The flexible manipulator has several features to help the proper valve placement. It provides five degrees of freedom for reaching the operative site via mini-thoracotomy where it adjusts the valve and expands it at the optimal position. The robot was evaluated by ten cardiac surgeons in a simulated surgical scenario: the ValveTech robot proved to be an alternative solution for targeted surgery; improving the quality of the valve implantation both for surgeons and patients... Read more
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Evaluation of a Wireless Tongue Tracking System on the Identification of Phoneme Landmarks
Visualizing tongue movement in real-time has the potential to improve therapy outcome for millions of people worldwide living with a speech sound disorder because the positioning of the tongue is crucial in the production of many phonemes to be intelligible. Our team has developed a wearable 3D tongue tracking system based on a wireless magnetic localization method. To evaluate its tracking accuracy, 2,500 tongue trajectories were recorded from 10 subjects uttering 25 phonemes. The results show that our system is capable of tracking tongue motion with positional errors in the order of few millimeters (median: 3.9 mm, Q3: 5.8 mm)... Read more
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Infusion Mechanisms in Brain White Matter and its Dependence of Microstructure: An Experimental Study of Hydraulic Permeability
The limited understanding of solute transport in brain white matter tissue has hindered optimisation of infusion-based drug delivery therapies. This paper describes the first direct measurement of hydraulic permeability in white matter subjected to infusion. Our experiments reveal the dependency of hydraulic permeability on the alignment between the flow direction and the orientation of the axonal fibres. This is particularly relevant for the successful development of infusion-based technologies for treatment of lethal tumours in brain, such as convection-enhanced delivery, which are based on the direct injection of drugs under positive pressure into the brain... Read more
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Towards 3D ultrasound guided needle steering robust to uncertainties, noise and tissue heterogeneity
This paper presents robust flexible needle steering for robotized punctures guided by 3D ultrasound (US) images. Reaching a target in biological tissue involves being able to detect the inserted needle in the 3D image, to plan a path from its current position and to control motion, at each instant. The proposed approach is able to face the low quality of images, the high variability of biological tissue and the limited ability to capture needle-tissue interactions in a model. Experiments on multi-material phantoms and ex-vivo biological tissue demonstrated the system ability to reach, accurately, US-defined targets using generated 3D helical paths... Read more
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CFD Assisted Evaluation of in Vitro Experiments on Bearingless Blood Pumps
The design of modern bearingless blood pumps requires detailed insights of the occurring shear forces within the pump in order to reduce blood damage. As the optimization by means of experimental shear-force analysis is often impractical, this work presents a computational fluid dynamic (CFD) simulation framework, based on Eulerian hemolysis models, to identify the sources of blood damage in bearingless centrifugal pumps. The outputs obtained with this framework are compared to experimental hemolysis tests conducted with ten different pump prototypes. As a result, this work provides design guidelines for improving the cell compatibility of future centrifugal blood pumps... Read more
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Fiber optic sensors-based thermal analysis of perfusion-mediated tissue cooling in liver undergoing laser ablation
Blood perfusion plays a key role for the ablation success, especially in the case of highly vascularized organs like liver. Aim of this work is to evaluate the vessel distance influence on the thermal gradient and the cooling of the tissue caused by blood perfusion during laser ablation. The proposed setup, based on Fiber Bragg Grating sensors (FBGs) around the laser applicator, permitted to measure the heat propagation and to observe a relevant tissue cooling near to the vessel... Read more
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Image guidance in deep brain stimulation surgery to treat Parkinson’s disease: a comprehensive review
Deep brain stimulation (DBS) is an effective therapy for Parkinson’s disease (PD). The success of the procedure depends heavily on the accurate placement of the electrode within the optimal therapeutic targets while avoiding vital structures that can cause adverse outcomes. Interventional guidance with medical imaging has greatly contributed to the development, outcomes, and safety of the procedure. With rapid technological advancements, it will further enhance the capacity and efficacy of the procedure. We present a comprehensive review on the state-of-the-art techniques in image-guided DBS surgery to treat PD, and discuss about the future directions on the topic... Read more
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Design and Comparison of Magnetically-Actuated Dexterous Forceps Instruments for Neuroendoscopy
Robot assistance is revolutionizing minimally invasive surgical (MIS) techniques. As robot assistance becomes standard in areas such as urology and general surgery, it remains largely absent in neurosurgery. The primary reason is a lack of dexterous wristed tools that are small and compact enough to maneuver within the confines of the brain. In this study, we present a wireless magnetic power transmission that enables the design of unconventional tiny wristed robot tools. By deploying the tools endoscopically within a silicone brain model, we demonstrate the feasibility of these novel devices for future neuroendoscopic robots... Read more
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A Wireless Implantable Passive Intra Abdominal Pressure Sensing Scheme via Ultrasonic Imaging of a Microfluidic Device
This work developed an implantable, low-cost, passive pressure sensor capable of measuring in situ IAP (intra-abdominal pressure) wirelessly using ultrasound imaging. The transducer consists of a pressure sensitive reservoir filled with water and a hydrophobic microchannel, both made of PDMS. A change of IAP will push the water from the reservoir into the channel with the in-channel fluid displacement in response to the applied pressure, which can be quantitatively analyzed by using a 40MHz ultrasound imaging system. The sensor is able to work in the physiological range of abdominal compartment syndrome with a highly linear sensitivity of 1.2kPa/30µm... Read more
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A breast-specific MR guided focused ultrasound platform and treatment protocol: first-in-human technical evaluation
Breast cancer remains one of the most common cancers among women. The development of novel technology for minimally-invasive treatments will provide important new treatment options for many breast cancer patients. This work presents a breast-specific magnetic resonance (MR) guided focused ultrasound system for the treatment of localized breast tumors. The unique design of the system allows for high quality MR images for treatment planning and assessment, target accuracy determination with volumetric magnetic resonance-acoustic radiation force imaging, and real time treatment monitoring with magnetic resonance thermometry. Technical specification for the system are provided as well as preliminary results from a first-in-human clinical trial... Read more
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Proactive Air Management in CT Power Injections: A Comprehensive Approach to Reducing Air Embolization
Prevention of air injection in contrast-enhanced Computed Tomography (CT) is an important topic. This work reviews air management approaches of contemporary power injectors, proposes a novel air management approach that is more proactive, and analyzes the injected air volumes under simulated clinical use. This proactive approach focuses on technology advances for air management prior to the injection, instead of simply monitoring air sensors during the injection. Results demonstrate a successful reduction in the amount of injected air under simulated use, which could translate in practice to fewer imaging artifacts and fewer workflow disruptions... Read more
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Muscle Path Wrapping on Arbitrary Surfaces
Musculoskeletal computer models are increasingly being used in biomedical research and clinical decision making. We propose a new method for simulating the dynamic interaction between muscles and bones in musculoskeletal models. Our method allows strand-based muscles to wrap directly on arbitrary, mesh-based surfaces, which permits more accurate modeling and tailoring to individual patients. It works with multiple and non-convex surfaces, and allows paths to come into and out of surface contact during dynamic musculoskeletal simulations. This new muscle wrapping method is implemented in the open source simulation system ArtiSynth (www.artisynth.org)... Read more
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Magnetic Control of a Flexible Needle in Neurosurgery
This paper presents a flexible needle steering system with magnetic control and fluoroscopic guidance for neurosurgical procedures. A permanent magnet at the proximal end of a flexible needle is steered by an external magnetic field, and the resultant tip-deflection angle bends the flexible body. The linear motion at the distal end of the needle actuates the needle insertion in soft tissues. The proposed needle steering system was tested using an in vitro brain phantom and ex vivo pig brain; the flexible needle was successfully maneuvered to follow the predefined straight and curved trajectories... Read more
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Fit to Burst: Toward Noninvasive Estimation of Achilles Tendon Load Using Burst Vibrations
In this study, we present a novel method of noninvasively estimating mechanical load in the Achilles tendon using burst vibrations. These vibrations, produced by a small vibration motor on the skin superficial to the tendon, are sensed by a skin-mounted accelerometer, which measures the tendon’s response to burst excitation under varying tensile load. Characteristic changes in the burst response profile as a function of tendon tension are observed and used as inputs to an ML model, which yields accurate (R2 = 0.85) estimates of ankle loading during gait. Preliminary results of a fully wearable ankle load monitor are also presented... Read more
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Estimating Reference Shape Model for Personalized Surgical Reconstruction of Craniomaxillofacial Defects
Current craniomaxillofacial (CMF) surgical planning techniques that rely on cephalometric analysis work reasonably well in correcting mild jaw deformities, but are inadequate for complex CMF defects (e.g., trauma). To alleviate this problem, we propose a method for estimating patient-specific reference bony shape models for planning of reconstructive surgery for patients with acquired CMF defects. Experimental results show that our method is capable of effectively recovering the patient’s normal facial bony shape in regions with defects, allowing CMF surgical planning to be performed accurately for a wider range of defects caused by trauma... Read more
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Development of a Chewing Robot with Built-in Humanoid Jaws to Simulate Mastication to Quantify Robotic Agents Release from Chewing Gums Compared to Human Participants
Medicated chewing gum has been recognised as a new advanced drug delivery method. Its potential has not yet been fully exploited because currently there is no gold standard for testing the gum in vitro. This study presents a novel humanoid chewing robot could provide opportunities for pharmaceutical companies to investigate and refine drug release from gum, with reduced patient exposure and costs... Read more
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Progress in nanorobotics for advancing biomedicine
Nanorobotics involves developing robotic devices to perform tasks at the nanometer scale. Nanorobotic systems can themselves be miniature in size (nanorobot), or they may be designed to interact with nano-sized matters (nanomanipulator). In the past decades, the breakthroughs of various nanorobotic systems and their applications in life sciences have offered novel possibilities for addressing biomedical issues and expanded the field of medical robotics, indicating that we are realizing the application scene of nanorobotics which has long been a fantasy in science fiction. Here, the recent advances in nanorobotics for biomedical applications are summarized and future perspectives are presented... Read more
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A Novel Theranostic Platform: Integration of Magnetomotive and Thermal Ultrasound Imaging with Magnetic Hyperthermia
This paper describes a theranostic system where a single coil is used to apply two different magnetic fields for magnetic hyperthermia (therapy) and magnetomotive ultrasound (diagnostics). This integrated system is proposed to address two of the main challenges that hinder magnetic hyperthermia to be translated into clinical routine: localizing the magnetic nanoparticles (magnetomotive ultrasound) and real-time temperature monitoring (ultrasound thermometry). We believe this study can open up a new horizon in magnetic hyperthermia, where planning, treating, and monitoring can be achieved through a single nanotheranostic agent and a cost-effective, portable, real-time and clinically available imaging device that uses non-ionizing radiation... Read more
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Automatic control of prosthetic socket size for people with transtibial amputation: Implementation and Evaluation
People wearing a lower leg prosthesis often experience discomfort or pain during the day because of changes in socket fit. To solve this problem, we created a motor-actuated prosthetic socket that automatically maintains socket fit by continuous adjustment of the socket size. A proportional-integral (PI) control system is implemented to adjust socket size based on data collected from an inductive sensor embedded within the socket wall. The sensed distance is representative of limb-to-socket distance. Experiments on participants with transtibial limb amputation verify that the system properly maintains and responds to a change in set point to maintain socket fit... Read more
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A Bayesian approach for coincidence resolution in microfluidic impedance cytometry
Microfluidic impedance cytometers are label-free systems for single-cell electrical characterization, which find application within life sciences, medicine, and environmental monitoring. However, their throughput and accuracy are limited by coincidences (i.e., two or more particles passing through the sensing zone nearly simultaneously), which may lead to errors in the measured particle properties. As an example, in a liquid biopsy application, a signal with unusually high amplitude could be interpreted as a circulating tumour cell while it is instead a doublet of red blood cells, or vice versa. In this work, a strategy for coincidence resolution is proposed... Read more
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Patient-Specific Sensor Registration for Electrical Source Imaging Using a Deformable Head Model
Electrical Source Imaging is a technique that estimates cortical sources responsible for scalp potentials measured by EEG electrodes. Electrical activity is modeled and reconstructed by formulating a forward problem that describes how electrical currents generated by the cortex travel to the scalp, and solving an inverse problem to estimate cortical sources responsible for measured scalp values. This work presents a model-based approach to electrode localization that is fully automatic, it requires only an MRI scan of the subject without any additional user input, thereby accelerating localization and streamlining clinical workflows... Read more
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A Machine Learning Enabled Wireless Intracranial Brain Deformation Sensing System
A leading cause of traumatic brain injury (TBI) is intracranial brain deformation from mechanical impact. This deformation is viscoelastic and differs from a traditional rigid transformation. Here, we present a machine learning enabled wireless sensing system, which can predict the trajectory of intracranial brain deformation by interpreting the magnetic sensor outputs created by the change in position of the implanted soft magnet. Both in vitro and in vivo experimental results showed an overall accuracy of over 92%, suggesting that this sensing scheme can be an effective tool for studying TBI due to in situ and real-time brain deformation prediction... Read more
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Mammography Image Quality Assurance Using Deep Learning
Image quality assurance is crucial in mammography to ensure reliable breast cancer diagnostics. Analyzing images of a technical phantom allows to routinely and reliably assess image quality. Current state-of-the-art analysis determines local image quality features by applying pre-processing and regression procedures for a set of repeatedly recorded images. This proof of concept paper demonstrates that mammography image quality assessment can benefit from deep learning. A neural network is trained on a large database of phantom images, and it is shown that the trained net retrieves the local image quality features already from single images without cumbersome pre-processing. This allows to maintain quality standards at significantly less labor... Read more
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Brain-Computer Interface-based Soft Robotic Glove Rehabilitation for Stroke
This paper presents the results of a study involving the use of a Brain-Computer Interface-based Soft Robotic Glove as a novel strategy in stroke rehabilitation. The technology uses the electroencephalogram signals from stroke patients to drive the assistive actions of the soft robotic glove to assist them in physically carrying out activities of daily living. The two-arm study showed prolonged improvements in FMA and ARAT scores although no significant intergroup differences were observed during the study. In addition, all of the patients in the BCI-SRG group also experienced a vivid kinesthetic illusion lasting beyond the active intervention period... Read more
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On the Safety of Human Body Communication
Human Body Communication (HBC) utilizes the human body as a physically secure, energy-efficient communication medium between devices on and around the body by sending electrical signals through the body. This paper provides a safety analysis of different modalities of HBC, for the first time, by comparing the current, electric field, magnetic field intensities from HBC with the established ICNIRP, IEEE, NIOSH safety standards through theory, analytical models and simulations. A study on a set of 7 subjects show that wearing an HBC enabled watch does not affect vital parameters including l heart rate, Mean Arterial Pressure, Respiration Rate, Peripheral Capillary Oxygen Saturation, Temperature... Read more
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Laparoscopic Renal Denervation System for Treating Resistant Hypertension: Overcoming Limitations of Catheter-based Approaches
The radical sympathectomy and percutaneous catheter-based renal denervation (RDN) are two techniques proposed to treat life-threatening resistant hypertension. However, sympathectomy has been abandoned due to the procedure being too invasive, and RDN resulted in variation in blood pressure reduction between patients due to suboptimal denervation. Thus, a method to effectively ablate renal nerves while not being very invasive is needed to treat the resistant hypertension patients. Here we propose a minimally invasive Laparoscopic Denervation System (LDS) to serve this unmet clinical need. The LDS employs a direct renal nerve ablation technique while not imparting thermal arterial damage... Read more
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Tissue Structure Updating for In Situ Augmented Reality Navigation using Calibrated Ultrasound and Two-level Surface Warping
In minimally invasive surgery, in situ augmented reality (AR) navigation systems are usually implemented using a glasses-free 3D display to represent the preoperative tissue structure. However, due to changes in intraoperative tissue, the preoperative tissue structure is not able to exactly correspond to reality. To solve this problem, we propose a method to update the tissue structure for in situ AR navigation in such way to reflect changes in intraoperative tissue. Experiments confirm that the novel AR navigation system based on updating the tissue structure will open up a better approach to provide accurate 3D see-through guidance... Read more
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Bio-Inspired Breastfeeding Simulator (BIBS): A Tool for Studying the Infant Feeding Mechanism
An experimental apparatus is developed for a better understanding of breastfeeding anomalies. This bio-inspired breastfeeding simulator (BIBS) mimics the infant’s complex suckling actions, including motions of the palate, tongue, and jaw, as well as sucking and vacuum pressure applied by the infant. BIBS includes a model of human breast, with a liquid mimicking the flow properties of milk, allowing external observations of flow. The design and construction of BIBS follows CT scanned images of the infants' oral cavities and clinical measurements and observations. This novel apparatus is the first to successfully mimic the compression and vacuum pressures exerted by infants... Read more
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Muscle-powered Counterpulsation for Untethered, Non-blood-contacting Cardiac Support: A Path to Destination Therapy
Heart failure remains one of the most costly diseases in the industrialized world, both in terms of healthcare dollars and the loss of human life. Despite decades of development in ventricular assist devices (VADs), the five-year survival rate for VAD patients remains barely above 50% due to secondary complications such as bleeding, driveline infection, and pump thrombosis associated with blood-contacting surfaces. Muscle-powered extra-aortic counterpulsation VAD that boosts cardiac function by squeezing the external surface of the ascending aorta during ventricular diastole holds potential as a safe and effective means to treat heart failure patients for long-term... Read more
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Soft Nanomembrane Sensors and Flexible Hybrid Bioelectronics for Wireless Quantification of Blepharospasm
This article introduces a soft nanomembrane bioelectronic system that offers wireless, quantitative detection of blepharospasm (BL). A set of computational and experimental studies of materials and mechanics provides the fundamental design factors for the soft bioelectronics. The nanomembrane electrodes, mounted around the eyes, are capable of measuring clinical symptoms, including the frequency of blinking, the duration of eye closures, and combinations of blinking and spasms. The deep-learning algorithm offers objective, real-time classification of critical pathological features in BL. The wearable electronic system outperforms the conventional manual clinical rating, proven by a pilot study with 13 patients... Read more
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High-Resolution Dynamic 31P-MR Spectroscopic Imaging for Mapping Mitochondrial Function
Abnormal mitochondrial metabolism is a hallmark of many prevalent diseases such as diabetes and cardiovascular disease; however, current understanding of mitochondrial function is mostly gained from studies on isolated mitochondria under nonphysiological conditions. This work presents a novel high-resolution dynamic 31P magnetic resonance spectroscopic imaging method that synergistically integrates physics-based models of spectral structures, biochemical modeling of molecular dynamics, and subspace learning, for metabolic mapping at high-spatiotemporal resolution. It enables in vivo imaging of phosphocreatine resynthesis rates, a well-established index of mitochondrial oxidative capacity, thus providing a powerful tool for longitudinal assessment of mitochondrial function in disease progression... Read more
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Robust Collaborative Clustering of Subjects and Radiomic Features for Cancer Prognosis
A robust collaborative clustering method has been developed in a Bayesian framework to simultaneously cluster patients and imaging features into distinct groups respectively, aiming to learn a compact set of discriminative features in radiomics studies. Experiments on synthetic data have demonstrated the effectiveness of the proposed approach in data clustering, and evaluation results on an FDG-PET/CT dataset of rectal cancer patients have demonstrated that the proposed method outperforms alternative methods in terms of both patient stratification and prediction of patient clinical outcomes... Read more
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An Integrated Robotic System for MRI-Guided Neuroablation: Preclinical Evaluation
This paper present preclinical trials of a robotic system for needle-based therapeutic ultrasound (NBTU) ablation of brain tumors under real-time magnetic resonance imaging (MRI) guidance. The system comprises of robotic manipulator and corresponding control electronics, the NBTU ablation system and applications for planning, navigation, and monitoring of the system. The integrated robotic system can place NBTU ablator at a desired target location in porcine brain and monitor the ablation in real-time via magnetic resonance thermal imaging (MRTI). The robotic system had a mean translational and rotational accuracy of 3.13±1.41 mm and 5.58±3.59° in 10 porcine trials... Read more
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The impact of ACL laxity on a bicondylar robotic knee and implications in human joint biomechanics
A robot model of the human knee provides a new way to investigate joint biomechanics. The specially designed joint has geometry copied from human bones scans and uses springs for ligaments. A knee cap (patella) and tendons transmit forces from an antagonistic pair of actuators, like in the human leg. This method overcomes many of the experimental limitations from using human tissue. The robot demonstrates the unique way in which the sliding of the joint surfaces allows the human knee mechanism to compensate when critical structures such as the anterior cruciate ligaments (ACL) are removed... Read more
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Target Flow-Pressure Operating Range for Designing a Failing Fontan Cavopulmonary Support Device
The Fontan procedure has enabled the survival of single ventricle patients into adulthood and reduced early morbidity. However, the lack of a sub-pulmonary ventricle to pump blood flow forward into the lungs have led to serious late complications, including a failing circulation. Using computational modeling of hemodynamics, this study aims to elucidate the hydraulic operating regions to be targeted for designing a cavopulmonary pump that can support Fontan patients with failing circulations. These operating regions also provide criteria for evaluating the off-label use of commercially available blood pumps for Fontan cavopulmonary support... Read more
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Millimeter-wave Substrate Integrated Waveguide Probe for Skin Cancer Detection
This work presents an innovative, low-cost, easy-to-fabricate, and simple-to-use probe that can detect early-stage skin cancer. As can be seen above, the probe scans the suspected skin area to enable capturing the reflection coefficient at each position. The collected data is then processed to infer the presence of skin cancer through a differential approach. In order to do this, a novel imaging function is utilized to enable the detection of relative permittivity changes with respect to the healthy region surrounding the suspected one, resulting in the 2D image depicted above... Read more
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Compact Optical Neural Probes with up to 20 Integrated Thin-Film μLEDs Applied in Acute Optogenetic Studies
Slender silicon-based optical probes comprising up to 20 thin-film micro light-emitting diodes (µLEDs) are realized as compact devices for optogenetic research. The μLEDs are structured on GaN-on-sapphire and transferred onto silicon using a wafer-level bonding and laser lift-off process. This technology allows processing the GaN layer stack from both sides, thereby maximizing the µLED efficiency to an emittance of 56 mWmm−2 at 5 mA. The thermal characterization of the optical probes reveals a temperature increase of up to 1.5 K. Acceptable neuronal responses are elicited at radiant flux values between 1.36 μW and 17.5 μW, successfully demonstrating layer-specific cortex stimulation... Read more
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A System for Characterizing Intraoperative Force Distribution during Operative Laryngoscopy
Investigators are increasingly finding that “smart” surgical instrumentation may improve clinical outcomes as greater tool-tissue contact forces are correlated with peri- and post-operative complications. While previous efforts to study intraoperative pressure distributions in otolaryngology have been limited by static equilibrium assumptions and cadaver-only testing, we present an integrated data acquisition system for detecting intraoperative forces and pressures during operative laryngoscopy using sixteen piezoresistive sensors. This low-cost and custom system can be calibrated within one hour prior to procedure with 1–2.5% error, and cadaver and live patient trials have shown comparable force and pressure data to literature values... Read more
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Computed Tomography-Based Modeling of Water Vapor-Induced Changes in Permittivity During Microwave Ablation
One can imagine that boiling water has such different physical properties than drinking water. Microwave ablation, a minimally invasive cancer treatment modality, increases the temperature of tissues even higher than the boiling temperature of water to eradicate cancerous tissues. To achieve an accurate simulation for microwave ablation treatment planning, we need to consider all the changes that occur in tissue properties. In this study, we used computed tomography imaging to measure the amount of water vapor that accumulates in tissues during microwave ablation. We modeled tissue properties as a function of vapor content using mixture equations which possessed greater accuracy than existing models... Read more
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Simultaneous Optimization of Patient–Image Registration and Hand–Eye Calibration for Accurate Augmented Reality in Surgery
For augmented reality (AR)-guided endoscopic surgery, patient–image registration and hand–eye calibration are essential steps and they have been separately performed so far with accumulating errors. In the proposed method, the two separate steps are integrated in a single step with minimized errors under the on-site AR condition. The AR superimposing accuracy can increase due to the reduced computational complexity of transformation processes and the compensated tracking errors of the position sensor…... Read more
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Disposable Paper-on-CMOS Platform for Real-time Simultaneous Detection of Metabolites
A fast and simple-to-use platform that combines an integrated circuit with paper microfluidics for simultaneous detection of multiple-metabolites appropriate for diagnostics is presented. The system measures changes in optical absorbance in functionalised paper to achieve a cost-effective and easy to implement system that is capable of multiple simultaneous assays. Potential sepsis metabolite biomarkers, glucose, and lactate, have been studied with the platform, achieving sensitivity within the physiological range in human serum. The combination of a low-cost paper strip and sensitive CMOS photodiodes makes our platform a robust, portable, and inexpensive biosensing device for multiple diagnostic tests in many applications... Read more
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Visual Servoed Robotic Mouse Oocyte Rotation
Both injection and biopsy of a mammalian cell require positioning and orientation of a biological cell in a three-dimensional space under a microscope. Manual cell manipulation and orientation is the most commonly used method that is based on a trial-and-error and direct cell poking approach. We present a system that is able to automatically rotate a mouse oocyte to a desired orientation based on pressure control and computer vision. Our methods improve existing techniques and provide a starting point for fast autofocusing and oocyte orientation prior to automatic ICSI or cell biopsy... Read more
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Toward a High-Throughput Wireless Smart Arena for Behavioral Experiments on Small Animals
We present a high-throughput wirelessly-powered and scalable smart arena for conducting behavioral experiments on freely behaving animals like rodents. It is made of multiple units known as EnerCage, operating in parallel, and fits in standard racks used in animal facilities. The multi-EnerCage-Homecage (mEHC) system increases the volume of data collected from more animals, while lowering the cost and duration of experiments. It is equipped with an auto-tuning mechanism to compensate for the resonance-frequency shifts caused by displacement of adjacent homecages. A 7-units prototype of the mEHC system is implemented and the effects of interference and resonance-frequency bifurcation are minimized... Read more
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Design of Ceramic Packages for Ultrasonically Coupled Implantable Medical Devices
Ultrasonic power transfer has emerged as an efficient method for powering and communicating with small and deeply implanted medical devices. However, most work utilizing ultrasonically-coupled implants relies on non-hermetic polymeric encapsulation materials rather than conventional metal or ceramic packaging materials due to the inherent acoustic impedance mismatch of metals and ceramics. Here, we develop models of ultrasonic power transfer through metals, examining flexural and bulk mode propagation, to determine optimal package design for ultrasonic power transfer. We utilize these results to build millimeter-scale hybrid ceramic/metal packages, and perform benchtop demonstrations of ultrasonic powering and communication with a packaged electrophysiology sensor... Read more
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Automated In Vivo Navigation of Magnetic-Driven Microrobots Using OCT Imaging Feedback
This paper presents a study on the navigation of microrobots in vivo by using optical coherence tomography (OCT) imaging feedback. The electromagnetic gradient field generated by a home-made electromagnetic manipulation system is magnetically modeled. With this model, the magnetic force acting on the microrobot is calculated, and the relationship between this force and the velocity of the microrobot is characterized. The findings are verified by the in vitro and in vivo environments, with the imaging feedback of the OCT imaging system and the actuation of the electromagnetic manipulation system. Experimental results have successfully demonstrated the effectiveness of the proposed approach... Read more
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Evaluation of Secrecy Capacity for Next-Generation Leadless Cardiac Pacemakers
Cardiac pacemakers are implanted medical devices designed to regulate abnormal cardiac rhythms. In the case of traditional pacemakers, the leads are considered to be the weakest link. This study proposes the keyless physical layer security (PLS) method to provide information confidentiality for next-generation leadless cardiac pacemakers. Electromagnetic simulations and experimental measurements were performed to prove the hypothesis of the availability of positive secrecy capacity in the near proximity of the human body. The research also evaluates the insecure volume in three-dimensional space around the body representing all the eavesdropper positions from which the pacemaker can be eavesdropped... Read more
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Monocular 3D Probe Tracking for Generating Sub-Surface Optical Property Maps From Diffuse Optical Spectroscopic Imaging
Light-based, or biophotonic, technologies are safe and portable tools for assessing tissue health. Above, we see how a handheld optical probe uses frequency modulated light to assess subsurface tissue composition by measuring molecular concentrations of absorbing and scattering media. However, assessing large tissue regions (e.g., in breast cancer) is traditionally a tedious and rigid process with ramifications for longitudinal follow-up. Here, we developed an overhead camera system that, paired with probe geometry knowledge, can track the probe in 3D as it is scanned across the tissue (as above), enabling real-time operator driven optical imaging... Read more
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Real-time Radiofrequency Ablation Lesion Depth Estimation Using Multi-Frequency Impedance with a Deep Neural Network and Tree-based Ensemble
A combination of different machine learning algorithms and a hardware setup that consists of an embedded system and a 3D-printed electrode device is used to monitor the progress of radiofrequency ablation depth on a perfused breast tissue model. The device at the center of the tissue model both applied the alternating current and collected the tissue impedance data at multiple frequencies, which is fed into tree-based ensemble (TE) models and a deep neural network (DNN). Their predictions showed a mean difference against physical measurements of 0.5 mm for the DNN and 0.7 mm for the TEs... Read more
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A Clinical Prototype Transrectal Diffuse Optical Tomography (TRDOT) System for In vivo Monitoring of Photothermal Therapy (PTT) of Focal Prostate Cancer
Prostate focal therapy targets only cancerous lesions in the prostate while ensuring no treatment effect on critical structures such as the rectum. In this work, we report on the assembly and testing of a transrectal diffuse optical tomography (TRDOT) system for monitoring the size of coagulated lesions generated during photothermal focal therapy of prostate tumors. During treatment, TRDOT signal is sensitive to the large increase in tissue optical scattering that occurs with thermally-induced tissue coagulation. Using ex vivo samples, we demonstrate that TRDOT can accurately map the size of a treatment-induced lesion and show that clinical measurements are feasible... Read more
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Optical Coherence Tomography Guided Robotic Needle Insertion for Deep Anterior Lamellar Keratoplasty
Deep anterior lamellar keratoplasty (DALK) is a promising form of partial-thickness cornea transplantation, but its popular “big bubble” technique frequently fails due to difficulty controlling a needle insertion into the cornea. We addressed the surgeon challenges that reduce success rates by demonstrating an optical coherence tomography (OCT)-guided, robotically stabilized workstation for manually or automatically performing DALK needle insertions. In a study with cornea fellows, we found that OCT visualization versus the standard stereo microscope was a key enabler in manual attempts and that our automatic robotic method met or exceeded the performance of cornea fellows... Read more
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Stimulation Pattern Efficiency in Percutaneous Auricular Vagus Nerve Stimulation: Experimental versus Numerical data
Percutaneous electrical stimulation of the auricular vagus nerve (pVNS) is an electroceutical technology. Stimulation patterns are empirical, which may lead to under-stimulation or over-stimulation. The objective is to assess the experimental efficiency of different stimulation patterns in volunteers and to compare it with in-silico ear models. Monophasic (MS), biphasic (BS) and a novel triphasic stimulation (TS) patterns were tested. TS indicates experimental superiority over BS which is superior to MS. Numerical results indicate a slight superiority of BS and TS over MS. TS yields the highest number of asynchronous action impulses. The study favors the novel TS pattern... Read more
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MRI Conditional Actively-Tracked Metallic Electrophysiology Catheters and Guidewires with Miniature Tethered Radio-Frequency Traps: Theory, Design and Validation
Cardiovascular interventional devices typically have long metallic braids or backbones to aid in steerability and pushability. However, electromagnetic coupling of metallic-based cardiovascular interventional devices with the radiofrequency (RF) fields present during Magnetic Resonance Imaging (MRI) can make a device unsafe for use in an MRI scanner. We aimed to develop MRI conditional actively-tracked cardiovascular interventional devices by sufficiently attenuating induced currents on the metallic braid/tube and internal-cabling using miniaturized resonant floating RF traps (MBaluns). We provided electromagnetic simulation revealing MBalun critical dimensions, along with phantom heating and swine experiments that validate the designs... Read more
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Stable Responsive EMG Sequence Prediction and Adaptive Reinforcement with Temporal Convolutional Networks
Movement prediction from EMG can be performed by compressing a short window of EMG into a feature-encoding that is meaningful for classification— an approach that can cause erratic prediction behavior. Temporal convolutional networks (TCN) leverage temporal information from EMG to achieve superior predictions for 3 simultaneous degrees-of-freedom that are more accurate and stable, have a very low response delay, and allow for novel types of interactive training. Addressing EMG decoding as a sequential prediction problem requires a new set of considerations that will lead to enhancements in the reliability, responsiveness, and movement complexity available from prosthesis control systems... Read more
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Foot-Controlled Robot-Enabled EnDOscope Manipulator (FREEDOM) for Sinus Surgery: Design, Control, and Evaluation
Functional endoscopic sinus surgery (FESS) is a common minimally invasive technique but remains manually operated by the surgeon with one hand holding the endoscope most of the time. This article reports a novel robotic system for side-by-side assistance of endoscope positioning with the surgeon in FESS from platform development to clinical validation. The design emphasizes clinical considerations for both operational safety and user ergonomics, which were validated by clinical trials to demonstrate good surgical applicability in terms of efficient robot set-up and enabling three-handed procedures performed by the surgeon alone, without disrupting the routine practice of FESS... Read more
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On-Chip Impedance Quantification of Parasitic Voltages During AC Electrokinetic Trapping
Monitoring the effectiveness and location of cell or particle trapping under microfluidic force fields is currently achieved by cumbersome imaging methods that require extensive microscopy to be conducted by a trained operator, with limited ability to rapidly trigger downstream decisions. We present an embedded circuit for an impedance sensor that directly interfaces to a microfluidic chip for the monitoring of cell or particle trapping based on the level and frequency response of parasitic voltage drops measured during AC electrokinetic manipulation, to enable assessment of trapping efficacy of the device geometry and to rapidly inform downstream cell separation decisions... Read more
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Development of Dopamine Sensor Using Silver Nanoparticles and PEG Functionalized Tapered Optical Fiber Structure
A medical diagnosis of dopamine used one of the most effective localized surface plasmon resonance (LSPR) optical methods in this study. LSPR technology has many unique features such as real-time monitoring, label-free detection, and smooth integration. Sensor is immobilized with silver-nanoparticles followed by functionalization of polyethylene glycol. Highly sophisticated instruments such as HR-TEM, UV-Vis-spectrophotometer, EDS, and SEM were used for the characterization of nanoparticles and immobilized probe. It shows the great selectivity towards detection of dopamine in the presence of other higher concentrated coexist biomolecules such as ascorbic acid. A noticeable improvement is recorded in the all-important sensing parameters... Read more
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Combined Single Cell Manipulation and Chemomechanical Modeling to Probe Cell Migration Mechanism during Cell-to-cell Interaction
During cell-to-cell interaction, spatial presentations of chemical and mechanical information are key parameters for cell migration. A chemomechanical model to assess the biochemical and biophysical modulators of single cell migration during cell-to-cell interaction can help to understand cell migration in a complex environment that is close to realistic in vivo situation. In the work, the issue is modeled based on molecular clutches, and experiment validation is implemented through single cell manipulation through optical tweezers. The results show that cell migration velocity caused by chemotaxis can be biased by dynamic adhesion force between cells... Read more
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A multiscale agent-based model of ductal carcinoma in situ
Breast cancer is the most frequently diagnosed cancer in the United States, and about 17% of these occur within the mammary gland duct, known as ductal carcinoma in situ (DCIS). We have developed a multiscale, lattice-free agent-based model of DCIS, incorporating both molecular and cellular scales, to study how phenotypic and signaling changes influence the key early stages of disease development. By simulating the effects of bidirectional feedback between these scales, we have gained valuable insights into how this complex interplay affects disease progression, and have identified key processes that may be optimal prognostic indicators of future disease advancement... Read more
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CMOS-compatible, Flexible, Intracortical Neural Probes
Flexible intracortical neural probes elicit a lower tissue response compared to rigid implants. However, silicon-based neural probes incorporating complementary metal-oxide-semiconductor (CMOS) circuitry offer improved scalability and functionality. We describe a novel neural implant combining short, needle-like CMOS-based probe tips with flexible polyimide cables. Ultra-thin shuttles enable their complete implantation into brain tissue. An optimized cable fabrication process based on ion beam and plasma etching increases line and pad density, thus minimizing the bond area between cable and probe tip to widths of 100 µm. The synergetic approach surpasses the limitations of each individual probe technology and should be considered in future developments... Read more
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Enhanced detection of bubble emissions through the intact spine for monitoring ultrasound-mediated blood-spinal cord barrier opening
Short burst, phase keying (SBPK) is a clinically relevant pulse scheme for focused ultrasound delivery to the spinal canal. We demonstrate that emissions from microbubbles exposed to these pulses can be detected through ex vivo human vertebrae, and that SBPK exposures can open the blood-spinal cord barrier (BSCB) in rats. Microbubbles were sonicated through ex vivo vertebrae and emissions were analyzed using short time Fourier analysis. Pulses were modified to include pulse inversion, which enhanced detection of acoustic signatures. In rats, opening was confirmed by MRI enhancement. Detection of the subharmonic was linked to tissue damage observed at histology... Read more
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An Automated Microrobotic Platform for Rapid Detection of C. diff Toxins
Clostridium difficile (C. diff) infection is a serious public health threat, and early diagnosis of this toxin-mediated disease is important. This paper presents a fluorescence imaging-integrated microrobotic system and related methods for automated and rapid detection of C. diff toxins. The automated mobile detection process finishes within 20 minutes, and then qualitative and semi-quantitative results are immediately given. This process is at least 8 times shorter than that of the conventional ELISA. The proposed microrobotic platform offers an automated, rapid and low-cost C. diff toxin detection technique that has good competency for future clinical use... Read more
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Wireless Hyperthermia Stent System for Restenosis Treatment and Testing with Swine Model
Stenting is a common approach to treating atherosclerosis, the main pathology that leads to cardiovascular disease causing thousands of death each day. Despite its proven efficacy, the long-term results of stenting are still limited by re-narrowing of stented artery known... Read more
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Toward Safe Retinal Microsurgery: Development and Evaluation of an RNN-based Active Interventional Control Framework
Retinal surgery is an excellent example of a high-demand dexterity procedure that may benefit from robotic systems. However, due to an incomplete understanding of a surgeon’s imminent intentional manipulations, the assistance provided to the surgeons by current robotic frameworks is... Read more
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A Deep Learning Framework for Single-Sided Sound Speed Inversion in Medical Ultrasound
Abnormalities in the tissue’s mechanical properties and structure, as well as their spatial arrangement, are useful in disease diagnosis and monitoring of disease progression. To this end, ultrasound shear wave elastography is gaining traction as a useful diagnostic tool for... Read more
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In-vivo Intrathecal Tracer Dispersion in Cynomolgus Monkey Validates Wide Biodistribution Along Neuraxis
Intrathecal (IT) delivery is a drug administration method that bypasses the blood-brain barrier by injecting therapeutic molecules directly into the central nervous system. In vivo tracer infusion experiments performed in cynomolgus monkeys dispel the common belief that in intrathecal drug... Read more
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Wireless Resonant Circuits Printed Using Aerosol Jet Deposition for MRI Catheter Tracking
Each year, nearly three-quarters of a million people in the US suffer from an ischemic stroke, caused by a blood clot in the vessels that feed the brain. Magnetic Resonance Imaging (MRI) provides the gold standard in determining whether it... Read more
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Generalized modeling framework of metal oxide-based non-enzymatic glucose sensor: concepts, methods, and challenges
For the 422 million diabetes patients worldwide, the glucose sensor is a life-saving technology. The first-generation sensors use glucose oxidase (GO_x) enzyme to convert glucose into gluconic acid and hydrogen peroxide (H_2 O_2). The amperometric response of H_2 O_2 determines... Read more
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Quantitative Assessment of Changes in Muscle Contractility Due to Fatigue During NMES: An Ultrasound Imaging Approach
Neuromuscular electrical stimulation (NMES) has been demonstrated to activate paralyzed or paretic muscles that in turn help restore limb functions (e.g., standing, walking, upper limb functions such as grasp and reaching) of persons with stroke, hemiplegia, paraplegia and other neurological... Read more
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Gradient-induced mechanical vibration of neural interfaces during MRI
The frequency spectrum of gradient pulses applied during the acquisition of MR images overlaps mostly with the mechanical resonance frequencies of active implanted medical devices such as neural implants. This raises the important question if it is possible to trigger... Read more
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Faster Gait Speeds Reduce Alpha and Beta EEG Spectral Power From Human Sensorimotor Cortex
Understanding how the human brain controls locomotion is a considerable neuroscience challenge that has required advancements in mobile neuroimaging methods. Mobile high-density electroencephalography (EEG) allows electrical brain activity to be measured non-invasively during gait, but these signals are prone to... Read more
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Continuum Robot with Follow the Leader Motion for Endoscopic Third Ventriculostomy and Tumor Biopsy
In a combined endoscopic third ventriculostomy (ETV) and endoscopic tumor biopsy (ETB) procedure, an optimal tool trajectory is mandatory to minimize trauma to surrounding cerebral tissue. Ideally, methods for performing this ETV/ETB procedure must ensure adequate visualization of and access... Read more
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Qualitative and Quantitative Assessment of Technical Skills in Percutaneous Coronary Intervention: In Vivo Porcine Studies
Technical skill assessment plays an important role in the professional development of an interventionalist in percutaneous coronary intervention (PCI), however, most of traditional assessment methods are time-consuming and subjective. This paper aims to develop objective and automatic assessment techniques for... Read more
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Perceptual Limits of Optical See-Through Visors for Augmented Reality Guidance of Manual Tasks
The current generation of consumer-level Optical-See Trough (OST) Head-Mounted Displays (HMDs) is not specifically designed for the peripersonal space. Indeed it generally renders the virtual content on a fixed focal plane located at a distance of 2 meters or more... Read more
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Pose Estimation of Periacetabular Osteotomy Fragments with Intraoperative X-Ray Navigation
State-of-the-art navigation systems for pelvic osteotomies use optical systems with external fiducials. In this paper, we propose the use of X-ray navigation for pose estimation of periacetabular fragments without external fiducial objects. A multiple-object, multiple-view, two-dimensional/three-dimensional registration pipeline was developed... Read more
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Low-Voltage Irreversible Electroporation Using a Comb-Shaped Contact Electrode
Irreversible electroporation (IRE) is a less invasive therapy to ablate tumor cells by delivering short intensive electric pulses more than a few kV via needle-like electrodes. However, general anesthesia is needed for the therapy to avoid muscle convulsions and contractions... Read more
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Image-based Artefact Removal in Laser Scanning Microscopy
Advances in laser scanning microscopy (LSM) have greatly extended its applicability in cancer imaging not only to observe dynamic biological processes, but also to quantitatively measure them. The fast acquisition, with high spatial and temporal resolution and extended field of... Read more
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An Ankle-Foot Prosthesis Emulator Capable of Modulating Center of Pressure
Several powered ankle-foot prostheses have demonstrated moderate reductions in energy expenditure by restoring pushoff work in late stance or by assisting with balance. However, it is possible that center of pressure trajectory modulation could provide even further improvements in user... Read more
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Pediatric Airway Stent Designed to Facilitate Mucus Transport and Atraumatic Removal
The standard treatment for tracheobronchomalacia in infants and children is to use positive pressure ventilation to prevent airway collapse. With a treatment period of 3-9 months, maintaining a child on a ventilator requires close monitoring to ensure regular mucus clearance... Read more
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Single-Site Devices for Conjoined Glucose Sensing and Insulin Delivery
Diabetes patients are increasingly using a continuous glucose sensor to monitor blood glucose and an insulin pump connected to an infusion cannula to administer insulin. Applying these devices requires two separate insertion sites, one for the sensor and one for... Read more
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Electric Stimulus-Responsive Chitosan/MNP composite Microbeads for a Drug Delivery System
Direct drug administration has several shortcomings, for eg, poor target localization and specificity, opsonization, undesired systemic exposure, etc. Stimuli controlled Drug Delivery Substrates (DDS) not only sterically shield the drug from premature renal flushing, but also introduce the possibility of... Read more
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4-D Flow MRI-Based Computational Analysis of Blood Flow in Patient-Specific Aortic Dissection
       Type B aortic dissection (TBAD) is a serious clinical emergency characterized by a split in the layers of the aortic wall which allows blood to enter a second channel known as false lumen. This disease impairs blood supply to body... Read more
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Real-Time Photoacoustic Thermometry Combined with Clinical Ultrasound Imaging and High-Intensity Focused Ultrasound
        High intensity focused ultrasound (HIFU) treatment is a promising non-invasive method for killing or destroying the diseased tissues by locally delivering thermal and mechanical energy without damaging surrounding normal tissues. In HIFU, measuring the temperature at the treatment site is... Read more
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A Hybrid Robotic System for Arm Training of Stroke Survivors: Concept and First Evaluation
                      This work describes a hybrid robotic system for arm recovery after stroke, combining EMG-triggered Functional Electrical Stimulation (FES) with a passive exoskeleton for upper limb suspension. The system was developed within the European project RETRAINER and was used in a... Read more
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In vivo Visualization of Brain Vasculature in Alzheimer’s Disease Model Mice through High-Resolution Ultrasound Blood Flow Mapping
     Objective: Cerebrovascular disorders are associated with Alzheimer’s disease (AD). Preclinical animal study is necessary for understanding AD pathogenesis and determining its optimal diagnosis and treatment strategies. Conventionally, the cerebral vasculature’s structure is analyzed through histological staining. However, functional analysis of... Read more
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A Minimally Invasive Hollow Microneedle with a Cladding Structure: Ultra-Thin but Strong, Batch Manufacturable
      Institution: National Key Laboratory of Micro/Nano Fabrication Technology, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, 800 Dongchuan RD. Minhang District, Shanghai 200240, China Description: With the development of micromachining technology, microneedles have been developed by academic laboratories... Read more
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Catheter Treatment of Ventricular Tachycardia: A Reference-Less Pace-Mapping Method to Identify Ablation Targets
       Ventricular tachycardia (VT) is a life-threatening arrhythmia. In patients with myocardial infarction, electrical activation of the ventricles is impaired by the remodelling of the infarcted area, which results in conduction blocks, and slow conducting zones with sparse surviving fibres. Slow... Read more
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Implantable Multi-modality Probe for Subdural Simultaneous Measurement of Electrophysiology, Hemodynamics, and Temperature Distribution
       The integration of the multi-channel measurement capabilities of near-infrared spectroscopy (NIRS), electrocorticography (ECoG), and negative temperature coefficient (NTC) thermistor sensors into a single device, having a compact profile similar to that of the subdural strip electrodes commonly used in neurosurgery,... Read more
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FeetBeat: A Flexible Iontronic Sensing Wearable Detects Pedal Pulses and Muscular Activities
      Human feet have long been considered in close association with whole-body health, from which abundant cardiovascular and skeletomuscular information can be extracted. In this study, we aim to develop the world’s first foot-based wearable system that can detect both pedal... Read more
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A Palm-Sized Cryoprobe System with a Built-in Thermocouple and Its Application in an Animal Model of Epilepsy
        We have studied a palm-sized cryoprobe system and showed that cryosurgery may be an effective treatment for epilepsy. Conventional cryoprobe systems have triple coaxial tubes. Since accurate temperature measurement of the probe tip is indispensable for reliable treatment of cryosurgery,... Read more
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Improving Performance of Devanagari Script Input-Based P300 Speller Using Deep Learning
  In P300 based BCI systems, eliciting ERP using the oddball stimulation will conceal the original P300 components in EEG signal. Therefore, it requires accurate detection of P300 components to precisely recognize the characters. For that purpose, conventional machine learning and... Read more
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High-Quality Immunohistochemical Stains through Computational Assay Parameter Optimization
Immunohistochemistry (IHC) has been the gold standard technique for cancer diagnostics and treatment choice for the past several decades. Immunostaining produces chromatic signal by exposing a tissue to antibodies. The quality of the stain depends on staining process parameters, i.e.... Read more
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A Review of Low-Intensity Pulsed Ultrasound for Therapeutic Applications
Ultrasound therapy has a long history of novel applications in medicine. Compared to high-intensity ultrasound used for tissue heating, low-intensity ultrasound has drawn increasing attention recently due to its ability to induce therapeutic changes without significant biological temperature increase. Low-intensity... Read more
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A Coaxial RF Applicator for Ultra-High Field Human MRI
In our work, we present a novel concept for the ultra-high-field (UHF) human magnetic resonance imaging (MRI) based on a coaxial cavity is described. Physical dimensions make the proposed conducting structure resonant at the required frequency and tuning lumped elements... Read more
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Wrap-Around Wearable Coils for Seamless Monitoring of Joint Flexion
Monitoring human body kinematics can open doors to innumerable applications in sectors including (a) healthcare (rehabilitation, and research on understanding complicated motor disabling conditions), (b) sports (rehabilitation and training), (c) gesture recognition, (d) gaming, and (e) virtual reality, among others. To... Read more
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A Framework for Measuring the Time-Varying Shape and Full-Field Deformation of Residual Limbs Using 3D Digital Image Correlation
Effective prosthetic socket design following lower-limb amputation depends upon the accurate characterization of the shape of the residual limb as well as its volume and shape fluctuations. This study proposes a novel framework for the measurement and analysis of residual... Read more
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Robotic Transrectal Ultrasound-Guided Prostate Biopsy
We present a robot-assisted approach for transrectal ultrasound (TRUS) guided prostate biopsy. The robot is a hands-free probe manipulator that moves the ultrasound probe with the same 4 degrees-of-freedom (DoF) that are used manually in transrectal procedures, closely replicating its... Read more
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A New RF Heating Strategy for Thermal Treatment of Atherosclerosis
Atherosclerosis contributes to major mortality and modality of cardiovascular diseases around the world. Angioplasty and stenting are the common treatments for blocked arteries induced by atherosclerosis in clinic. In the treatment, the narrowed artery lumen is effectively opened by the... Read more
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Fluidic bypass structures for improving the robustness of liquid scanning probes
Liquid scanning probes enable interfacing with biological surfaces and are compatible with a wide range of workflows and bioanalytical applications. To facilitate rapid and widespread adoption of liquid scanning probes in research, as well as in diagnostics, their operational robustness... Read more
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3D Microwave Tomography Using the Soft Prior Regularization Technique: Evaluation in Anatomically-Realistic MRI-Derived Numerical Breast Phantoms
In this work, we present methods and results for fusion of magnetic resonance imaging(MRI) breast images with microwave tomography through a soft prior regularization technique. This method incorporates accurate boundary location of different regions of interest from MRI as spatial... Read more
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Three-Dimensional Electrical Impedance Tomography with Multiplicative Regularization
It is known that the image reconstruction problem of electrical impedance tomography (EIT) is ill-posed. As a result, a regularization scheme is usually applied to alleviate the ill-posedness. In the commonly used Tikhonov regularization scheme, a regularization function is added... Read more
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Correlation Between Optical Fluorescence and Microwave Transmission During Single-cell Electroporation
      Electroporation is a widely used physical (as opposed to chemical or biological) method to enhance the permeability of a cell membrane, with the degree of enhancement determined by applied field magnitude, duration, frequency et al. Traditional electroporation is based on... Read more
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A New Image Similarity Metric for Improving Deformation Consistency in Graph Based Groupwise Image Registration
   In graph based groupwise image registration (G-GIR), a graph representing the input images is constructed using an image similarity metric (ISM). The ISM defines the graph edges that link image pairs. Similar images are connected via short edges. Based on... Read more
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Detection of Vesicoureteral Reflux using Electrical Impedance Tomography
       Vesicoureteral Reflux (VUR) is characterized by the backflow of urine from the bladder to the kidneys and is the most common congenital urinary tract abnormality in children. The condition predisposes children to urinary tract infections (UTIs) and kidney damage. Typically,... Read more
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Self-scanned HIFU ablation of moving tissue using real-time hybrid US-MR imaging
          High Intensity Focused Ultrasound (HIFU) treatment in the abdominal cavity is challenging due to the respiratory motion. In the self-scanning HIFU ablation method the focal spot is kept static and the heating pattern is obtained through natural tissue motion. This... Read more
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Achieving Automated Organelle Biopsy on Small Single Cells Using a Cell Surgery Robotic System
       Studies on bulk tissues only provide a statistical average of several actions taken place in different cells. Single cell investigation may disclose further important and in-depth information. Single cell surgery such as manipulation or removal of subcellular components or/and organelles... Read more
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Sparse EEG Source Localization Using LAPPS: Least Absolute l -P (0 < p < 1) Penalized Solution
The ill-posed nature of electroencephalogram-EEG (or related magnetoencephalogram-MEG) poses a great challenge in neuroimaging. Considering that EEG electrode sensors measure the scalp potentials rather than directly measuring neural activities inside the head, a lot of research in recent years has... Read more
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Electrophysiological Brain Connectivity: Theory and Implementation
Brain function and dysfunction are encoded in networks within the brain that are distributed over 3-dimensional space and evolves in time. It is of great importance to image brain activation and functional connectivity which are the building blocks of neural... Read more
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Real-time Temperature Measurements of HMEC-1 Cells during Inflammation Production and Repair detected by Wireless Thermometry
Cell inflammation process is reflected through real-time in situ cellular temperature changes. A wireless thermometry system for in situ cellular temperature measurements was used in an incubator to detect the HMEC-1 cellular temperature under lipopolysaccharide inflammation production and norepinephrine for... Read more
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Reference-Based Integral MR-EPT: Simulation and Experiment Studies at 9.4T MRI
Current integral-equation (IE) based MR electrical properties tomography (EPT) methods utilize simulated incident radio-frequency (RF) fields, which are inaccurate and lead to reconstruction errors. To improve the accuracy and practicability of IE-based MR-EPT methods, a new approach is presented that... Read more
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Encapsulation Approaches for In-Stent Wireless Magnetoelastic Sensors
Prior work has shown that wireless magnetoelastic sensors can signal impending stent occlusion, thereby potentially avoiding the most lethal risks of the occlusion. Encapsulation of these sensors within the small inner lumen of the stent remains a critical challenge. The... Read more
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A Single-Scan Inhomogeneity-Tolerant NMR Method for High-Resolution 2D J-Resolved Spectroscopy
NMR spectroscopy serves as one of the most commonly used detection techniques with non-invasive properties. Particularly, 2D homonuclear J-resolved NMR spectroscopy, revealing chemical shifts and J couplings along two independent dimensions, has been widely applied to molecular conformational elucidation, metabolite... Read more
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Micro-coil Design Influences the Spatial Extent of Responses to Intracortical Magnetic Stimulation
Electrical stimulation via cortically-implanted electrodes has been proposed to treat a wide range of neurological disorders. Effectiveness has been limited however, in part due to the inability of conventional electrodes to activate specific types of neurons while avoiding other types.... Read more
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A Machine Learning Shock Decision Algorithm for use during Piston-driven Chest Compressions
High quality chest compressions during cardiopulmonary resuscitation (CPR) and an early defibrillation are key to improve outcome in out-of-hospital cardiac arrest. Compressions must be interrupted for a reliable shock advice decision in the defibrillator because they induce artifacts in the... Read more
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In vivo Visualization of Vasculature in Adult Zebrafish by using High-Frequency Ultrafast Ultrasound Imaging
Zebrafish has been recently considered an ideal vertebrate for studying developmental biology, genetics, particularly for modeling tumorigenesis, angiogenesis, and regeneration in vivo. However, when a zebrafish matures completely, particularly if the specimen is from a wild-type line, stripes are evident... Read more
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Adaptive and Wireless Recordings of Electrophysiological Signals during Concurrent Magnetic Resonance Imaging
Simultaneous recordings of fMRI and electrophysiological signals, e.g. electroencephalography (EEG), electrocorticography (ECoG), and local field potentials (LFP), may help to bridge neural activity across various spatial and temporal scales. However, the MRI system is a hostile environment for recording bioelectric... Read more
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Wearable Devices for Precision Medicine and Health State Monitoring
   A key requirement for precision medicine is the ability to define clinically-relevant subgroups that enable improved patient management as well as the elucidation of disease mechanisms. The ability to define subgroups requires measurements with high information content and with a... Read more
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Patient-Specific Computational Simulations of Hyperpolarized 3He MRI Ventilation Defects in Healthy and Asthmatic Subjects
     Combined, medical imaging data and respiratory computer simulations may facilitate novel insight into pulmonary disease phenotypes, including the relationship between its structure and function. This integration may enable improved classification and treatment of severe asthma. Severe asthma (15% of asthmatics)... Read more
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Optogenetic Excitation of Ipsilesional Sensorimotor Neurons is Protective in Acute Ischemic Stroke: a Laser Speckle Imaging Study
     Brain stimulation has recently been reported to be a promising technique for stroke intervention through directly modulating the metabolism in brain. However, most brain stimulation techniques have limitations in precision and are not able to induce cell-specific modulation on the... Read more
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Epilepsy-on-a-chip System for Antiepileptic Drug Discovery
    Development of antiepileptic drugs is currently complicated by the long time course of epileptogenesis. This process occurs on a time scale of weeks to months in animal models, and takes up to two weeks in an in vitro organotypic hippocampal... Read more
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3D Measurements of Acceleration-Induced Brain Deformation via Harmonic Phase Analysis and Finite-Element Models
        Measuring brain deformation enables researchers to better understand traumatic brain injuries and to develop experimentally verified computer models to design and evaluate preventive strategies. Although motion can be observed using medical imaging, quantifying fast tissue deformation based on inertially-induced motion... Read more
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Generation of Patient-Specific Cardiac Vascular Networks: a Hybrid Image-Based and Synthetic Geometric Model
Image-based models derived from CT angiography are being used clinically to simulate blood flow in the coronary arteries of individual patients. However, image resolution limits vessel segmentation to the larger epicardial vessels. To simulate blood flow into the myocardium, generation... Read more
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A New Modeling Method to Characterize the Stance Control Function of Prosthetic Knee Joints
Biomechanical models can inform design and optimization of prosthetic devices by connecting empirically-derived biomechanical data to device design parameters. A new method is presented to characterize the function of prosthetic stance control under mobility conditions associated with activities of daily... Read more
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Quantification and Analysis of Laryngeal Closure from Endoscopic Videos
At present, there are no objective techniques to quantify and describe laryngeal obstruction, and the reproducibility of subjective manual quantification methods is insufficient, resulting in diagnostic inaccuracy and a poor signal-to-noise ratio in medical research. In this work, a workflow... Read more
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Smart Cell Culture Monitoring and Drug Test Platform Using CMOS Capacitive Sensor Array
Integrated Microfluidic-Microelectronic Systems have recently received significant interest, as a new paradigm in the design and implementation of chemical/biological analysis platforms, for both clinical and research purposes. This paper presents a novel method for monitoring drug cytotoxicity using a hybrid... Read more
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Acousto-optic Catheter Tracking Sensor for Interventional MRI Procedures
RF induced heating is a significant safety concern for Magnetic Resonance Imaging (MRI) especially when long metallic structures are inserted in the body during interventional MRI procedures. Current position tracking sensors used during interventional MRI rely on long conductor cables... Read more
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Non-invasive Treatment Efficacy Evaluation for HIFU Therapy Based on Magneto-Acousto-Electrical Tomography
As a newly developed non-invasive treatment approach, high-intensity focused ultrasound (HIFU) has received considerable attention in the past decades due to the fast thermal coagulation of tumor cells. To ensure the treatment efficacy with minimized damage to the surrounding healthy... Read more
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Background Removal and Vessel Filtering of Non-Contrast Ultrasound Images of Microvasculature
Conventional ultrasound Doppler imaging using classic FIR and IIR wall filters prohibits visualization of the small vessels due to strong Fourier spectral overlap between tissue and blood echoes. A clutter removal method is proposed that utilizes spatiotemporal coherence of the... Read more
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Efficient Bronchoscopic Video Summarization
Bronchoscopy enables many minimally invasive chest procedures for diseases such as lung cancer and asthma. Guided by the bronchoscope’s video stream, a physician can navigate the complex three-dimensional (3-D) airway tree to collect tissue samples or administer a disease treatment.... Read more
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Predicting Athlete Ground Reaction Forces and Moments From Spatio-temporal Driven CNN Models
Conventional methods to generate ground reaction forces and moments (GRF/M) required for traditional inverse dynamics estimation of athlete joint forces and loads are confined to biomechanics laboratories far removed from the sporting field of play. This has been an ongoing... Read more
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Model-based Sparse-to-dense Image Registration for Realtime Respiratory Motion Estimation in Image-guided Interventions
Intra-interventional respiratory motion estimation is an essential part of modern radiation therapy delivery or high intensity focused ultrasound systems. The treatment quality could tremendously benefit from more accurate dose delivery using realtime motion tracking based on magnetic-resonance (MR) or ultrasound... Read more
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An Intracardiac Flow Based Electromagnetic Energy Harvesting Mechanism for Cardiac Pacing
Contemporary cardiac implantable electronic devices such as pacemakers or event recorders are powered by primary batteries. Device replacement due to battery depletion may cause complications and is costly. To overcome these limitations, a new energy harvesting device has been investigated... Read more
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A Portable Passive Rehabilitation Robot for Upper-Extremity Functional Resistance Training
Loss of arm function is common after neurological injuries, such as stroke or cerebral palsy. Robotic devices that address muscle strength deficits in a task-specific manner can assist in the recovery of arm function; however, current devices are typically too... Read more
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Learning Patterns of Pivoting Neuromuscular Control Training-Towards a Learning Model
Over the last decades, lower limb therapy using locomotion devices has gained popularity in clinics to improve lower limb functions; however, from these studies, how the learning patterns over the course of a long-term training program change are unknown. Especially,... Read more
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Model of Impedance Changes in Unmyelinated Nerve Fibres
Electrical Impedance Tomography (EIT) is a technique able to image electrical impedance changes (dZ) in tissue by injecting alternating current and recording surface voltages. EIT has been shown to be able to visualise impedance changes related to neuronal depolarization over... Read more
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An Automated Method for Multi-DOF Cell Rotational Control Contributing to Orientation-based Cell Surgery Applications
Orientation control of biological cells has gained much attention recently due to the fact that cell rotation is both a basic and vital cell micromanipulation technique involved in many orientation-based cell surgery applications. These applications include cell injection, preimplantation genetic... Read more
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A Method for Rapid, Reliable, and Low-Volume Measurement of Lithium in Blood for Use in Bipolar Disorder Treatment Management
Bipolar Disorder (BD) can seriously impair a person’s life if not effectively treated. Lithium (Li) offers the most successful long-term management of BD, but it entails a considerable risk to the patient if not closely monitored to ensure concentrations are... Read more
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Video Magnification Applied in Ultrasound
Biological tissues such as the myocardium or the artery walls are subject to fast and complex phenomena which are related to their physical properties (geometry, composition, stiffness, etc.) as well as their function. Imaging these characteristics is essential from a... Read more
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Wireless thermometry for real-time temperature recording on thousand-cell level
It is vitally necessary to measure the cellular temperature to fully understand life sciences. A method allowing to measure the cellular temperature for a normal growing state without doing damage to the cells and disturbing their intercellular communication is needed.... Read more
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Medical Image Synthesis with Deep Convolutional Adversarial Networks
Medical imaging plays a critical role in various clinical applications. However, due to multiple considerations such as cost and radiation dose, the acquisition of certain image modalities may be limited. Thus, medical image synthesis can be of great benefit by... Read more
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RF Channel Modeling for Implant-to-Implant Communication and Implant to Sub-Cutaneous Implant Communication for Future Leadless Cardiac Pacemakers
The increase in functional sophistication and complexity of implantable medical devices has resulted in the need for facilitating communication between one implanted device and another and/or external devices such as monitoring device and programming console. But, propagation of radio-frequency (RF)... Read more
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Is EMG a Viable Alternative to BCI for Detecting Movement Intention in Severe Stroke?
EEG-based brain-computer interface (BCI) has been used to detect movement intention in severely affected stroke patients during assisted therapy, but current EEG-BCI systems are not practical for routine clinical use. If detectable in this population, residual EMG in the target... Read more
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Distortion Distribution of Neural Spike Train Sequence Matching with Optogenetics
Optogenetics, named “Breakthrough of the Decade” by Science Magazine, gives scientists the ability to directly control individual neurons with pulses of light. The technique involves genetic modification of neurons, causing them to express light-sensitive proteins called opsins. When exposed to... Read more
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Three-Dimensional Brain-Computer Interface Control through Simultaneous Overt Spatial Attentional and Motor Imagery Tasks
Brain-computer interfacing (BCI) is a promising method for providing alternative connections between the brain and the outside world in concert with natural connections or re-establishing natural limb movement in cases where these have been potentially disrupted by disease or injury.... Read more
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Ballistocardiogram-Based Approach to Cuff-Less Blood Pressure Monitoring: Proof-of-Concept and Potential Challenges
The goal of this study was to propose and establish the proof-of-concept of an ultra-convenient cuffless blood pressure (BP) monitoring approach based on the ballistocardiogram (BCG).  The proposed approach monitors systolic and diastolic BP (SP and DP) independently by exploiting... Read more
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Real-Time Blood Pressure Estimation From Force-Measured Ultrasound
Common techniques to measure blood pressure include an arterial catheter, an oscillometric pressure cuff, or an auscultatory pressure cuff. Oscillometric and auscultatory cuffs have an associated error, cannot be used continuously, and fully collapse the brachial artery. An auscultatory cuff... Read more
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Bi-Modal Arterial Compliance Probe for Calibration-Free Cuffless Blood Pressure Estimation
Non-invasive measurement of Blood Pressure (BP) has well-established utility in screening, clinical diagnosis and patient follow-up for a variety of critical disease conditions. Each usage scenario of BP poses unique functional requirements and challenges. The emerging field of non-invasive, cuffless... Read more
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Cuffless Estimation of Blood Pressure: Importance of Variability in Blood Pressure Dependence of Arterial Stiffness Across Individuals and Measurement Sites
Measuring arterial pulse transit time (PTT) to estimate blood pressure (BP) without conventional brachial cuff-based measurement is not new, but is a focus of current wearable technologies research. Much research pertains to efficient, accurate sensing of artery-related waveforms, yet the... Read more
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Information-Theoretic Approach and Fundamental Limits of Resolving Two Closely-Timed Neuronal Spikes in Mouse Brain Calcium Imaging
Calcium imaging has become a standard tool in neuroscience to record neural activity over large populations of neurons. Calcium sensor kinetics and signal-to-noise ratio significantly impact the precision of spike time estimation and spike detectability from the recorded optical signals.... Read more
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Electromagnetic Brain Source Imaging by Means of a Robust Minimum Variance Beamformer
Adaptive beamformer methods have been used extensively for functional brain imaging using EEG/MEG surface recordings. However, the sensitivity of beamformers to model mismatches impedes their widespread application, in practice. In this study, we propose a state-of-the-art technique, termed robust minimum... Read more
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Model-Based Analysis of Electrode Placement and Pulse Amplitutde for Hippocampal Stimulation
A brain implant performs best when it is properly adapted to the anatomy of the region with which it is meant to interface. Multiple-electrode arrays provide a system which can be adapted to various tissue geometries. Computational models of stimulating... Read more
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Topological Properties of the Structural Brain Network in Autism via ε-neighbor Method
When a structural brain network is constructed by the existing parcellation methods such as the automated anatomical labeling (AAL), the topological properties of the network change depending on the scale of parcellation and arbitrary connectivity matrix thresholding. To overcome these... Read more
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Accelerated Cardiac Diffusion Tensor Imaging Using Joint Low-Rank and Sparsity Constraints
Cardiac diffusion tensor imaging (CDTI) is a non-contrast-enhanced, non-invasive technique that shows great promise in assessing myofiber orientation and organization, thus offering insight to the pathophysiological fiber dynamics of various cardiovascular diseases. However, it is yet to be clinically practical... Read more
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Automated In Vivo Sub-Hertz Analysis of Viscoelasticity (SAVE) for Evaluation of Breast Lesions
Many breast tumors found by palpation manifest as stiff masses. The stiffness of tumor is related to a mechanical property known as elasticity. Elastography methods use tissue elasticity as a biomarker to provide invaluable information that improves classification of the... Read more
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Deformable Image Registration Using Cue-aware Deep Regression Network
Modern medical image analysis often has to deal with large-scale multi-center data, which requires the deformable registration satisfy the data diversity in clinical applications. We propose a novel deformable registration method, which is based on a cue-aware deep regression network,... Read more
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A Cascaded Deep Convolutional Neural Network for Joint Segmentation and Genotype Prediction of Brainstem Gliomas
Brainstem gliomas (BSGs) are a cancerous glioma tumor that occur in the brainstem. Diffuse intrinsic pontine gliomas (DIPG) account for 80% of BSGs in children and 45~50% in adults. Nearly 80% of pediatric DIPGs are induced by reprogramming the histone... Read more
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Estimating Brain Connectivity with Varying-Length Time Lags Using a Recurrent Neural Network
Computer-aided estimation of brain connectivity aims to reveal information propagation in brain automatically, which has great potential in clinical applications, e.g. epilepsy foci diagnosis. Granger causality is an effective tool for directional connection analysis in multivariate time series. However, most... Read more
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Automatic Recognition of fMRI-derived Functional Networks using 3D Convolutional Neural Networks
Current fMRI data modeling techniques such as Independent Component Analysis (ICA) and Sparse Coding methods can effectively reconstruct dozens or hundreds of concurrent interacting functional brain networks simultaneously from the whole brain fMRI signals. However, such reconstructed networks have no... Read more
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Decoding Covert Somatosensory Attention by a BCI System Calibrated With Tactile Sensation
Objective: We propose a novel calibration strategy to facilitate the decoding of covert somatosensory attention by exploring the oscillatory dynamics induced by tactile sensation. Methods: It was hypothesized that the similarity of the oscillatory pattern between stimulation sensation (SS, real... Read more
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Feasibility of Automatic Error Detect-and-Undo System in Human Intracortical Brain-Computer Interfaces
Brain-computer interfaces (BCIs) aim to help people with paralysis to improve their communication and independence. Intracortical BCIs (iBCIs) have shown promising results in pilot clinical trials. Despite the performance improvements over the last decades, BCI systems still make errors that... Read more
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Fusing Partial Camera Signals for Non-Contact Pulse Rate Variability Measurement
Remote camera-based measurement of physiology has great potential for healthcare and affective computing. Recent advances in computer vision and signal processing have enabled photoplethysmography (PPG) measurement using commercially-available cameras. However, there remain challenges in recovering accurate non-contact PPG measurements in... Read more
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Skull Modeling Effects in Conductivity Estimates Using Parametric Electrical Impedance Tomography
We estimate scalp, skull, compact bone and marrow bone electrical conductivity values using Electrical Impedance Tomography (EIT) measurements and assess the influence of skull modeling details on the estimates. We collected high density EIT data with 128- and 256-channel EEG... Read more
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Localization of Origins of Premature Ventricular Contraction by Means of Convolutional Neural Network from 12-lead ECG
Objective: This paper proposes a novel method to localize origins of premature ventricular contractions (PVCs) from 12-lead electrocardiography (ECG) using convolutional neural network (CNN) and a realistic computer heart model. Methods: The proposed method consists of two CNNs (Segment CNN... Read more
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Screening for Cognitive Impairment by Model Assisted Cerebral Blood Flow Estimation
Alzheimer’s disease is a progressive and debilitating neurodegenerative disease; one in ten people aged 65 and older have it. As there is no cure for Alzheimer’s disease, early diagnosis is crucial so that mitigating treatments can be initiated as soon... Read more
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Unambiguous Identification and Visualization of an Acoustically Active Catheter by Ultrasound Imaging in Real Time: Theory, Algorithm, and Phantom Experiments
Ultrasound-guided navigation of intracardiac catheters during minimally invasive procedures can be challenging due to the inability of B-mode ultrasound to distinguish the distal end of catheter from its body and the surrounding tissue. To better visualize the distal tip and... Read more
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Computerized Lung Sound Screening for Pediatric Auscultation in Noisy Field Environments
Chest auscultations offer a non-invasive and low-cost tool for monitoring lung disease. However, they present many shortcomings, including inter-listener variability, subjectivity, and vulnerability to noise and distortions. This work proposes a computer-aided approach to process lung signals acquired in the... Read more
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Computationally Efficient Algorithms for Sparse, Dynamic Solutions to the EEG Source Localization Problem
Electroencephalography (EEG) and magnetoencephalography noninvasively record scalp electromagnetic fields generated by cerebral currents, revealing millisecond-level brain dynamics useful for neuroscience and clinical applications. Estimating the currents that generate these fields, i.e., source localization, is an ill-conditioned inverse problem. Solutions to... Read more
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Micromagnetic Stimulation of the Mouse Auditory Cortex In Vivo Using an Implantable Solenoid System
Electromagnetic stimulation is widely used to activate the peripheral and central nervous system and treat neurological disorders. However, they have several drawbacks such as their large device size and poor focality. Recent studies have reported that micromagnetic stimulation (µMS), which... Read more
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A Functional-genetic Scheme for Seizure Forecasting in Canine Epilepsy
Epilepsy is a chronic condition characterized by recurrent, spontaneous, and unpredictable seizures resulting from the abnormal and excessive synchronization of groups of neurons. While first line of treatment consists of anti-epileptic medication, about a third of patients are refractory. Epilepsy... Read more
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In-Ear Audio Wearable: Measurement of Heart and Breathing Rates for Health and Safety Monitoring
This paper examines the integration of a noninvasive vital sign monitoring feature into the workers’ hearing protection devices (HPDs) by using a microphone positioned within the earcanal under the HPD. Twenty-five test-subjects were asked to breathe at various rhythms and intensities... Read more
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A Brain–Computer Interface Based on Miniature-Event-Related Potentials Induced by Very Small Lateral Visual Stimuli
Traditional visual brain-computer interfaces (BCIs) was faced with the dilemma of whether or not to use large-size visual stimuli to code instructions. On the one hand, to overcome the noisy electroencephalography (EEG) environment, scientists preferred to use strong visual stimuli... Read more
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Stimulation Efficiency With Decaying Exponential Waveforms in a Wirelessly Powered Switched-Capacitor Discharge Stimulation System
Implantable pulse generators (IPGs) that use a switched-capacitor discharge stimulation (SCDS) system and are wirelessly powered via an inductive transcutaneous link can be made significantly smaller than conventional IPGs powered by implantable batteries. The SCDS system is more energy-efficient at... Read more
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Ear-EEG-Based Objective Hearing Threshold Estimation Evaluated on Normal Hearing Subjects
Integration of auditory evoked potential techniques in hearing aids potentially enable assessment of the users hearing on a regular basis. Hearing threshold levels can be estimated in the clinic using the objective EEG-based technique of auditory steady state response (ASSR).... Read more
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Limb Position Tolerant Pattern Recognition for Myoelectric Prosthesis Control with Adaptive Sparse Representations from Extreme Learning
Electromyogram (EMG) signals can be used to decode the intended movements of an amputee for control of a dexterous upper-limb prosthesis. However, normal prosthesis use involves changes in upper-limb positions that influence the EMG signals, hindering the ability of pattern... Read more
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Optimization-Based Image Reconstruction from Low-Count, List-Mode TOF-PET Data
Time-of-flight (TOF) positron-emission tomography (PET) has increasingly been adopted as an important quantitative imaging tool in basic and clinical applications. Improving image quality via advanced image reconstruction methods remains an area of active interest. In particular, it is of practical... Read more
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A Novel Telemanipulated Robotic Assistant for Surgical Endoscopy: Preclinical Application to ESD
Intraluminal surgery is a very attracting technique for surgical procedures in the digestive tract because they limit trauma, avoid any visible scar for the patient and allow direct access to pathology. However, these are very demanding techniques for surgeons when... Read more
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Real-Time 3D Microwave Monitoring of Interstitial Thermal Therapy
Minimally invasive thermal treatments, such as microwave ablation, have emerged as safer, faster, and more precise alternatives to surgery for many soft tissue cancers, including liver and kidney. Their efficacy and applicability to higher-risk cases (e.g., close proximity to blood... Read more
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Effect of Tissue Heterogeneity on the Transmembrane Potential of Type-1 Spiral Ganglion Neurons: A Simulation Study
Electric field applied by cochlear implants stimulates the intact type-1 spiral ganglion neurons (SGNs) in the Rosenthal’s canal of the human cochlea. As a result, transmembrane potential of the SGNs exceeds threshold value and fires the action potential through the... Read more
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Mechanical Imaging of Soft Tissues with a Highly Compliant Tactile Sensing Array
The mechanical imaging of lumps in tissues via surface measurements can permit the noninvasive detection of disease-related differences in body tissues, and can aid the documentation of tissue changes over time. This has motivated the development of new electronic sensing... Read more
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Novel Quantitative Analytical Approaches for Rotor Identification and Associated Implications for Mapping
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in humans, which is believed to be maintained by rapid reentry sources (rotors). One treatment option is catheter ablation, which targets the tissue responsible for the AF initiation and maintenance,... Read more
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A Three-Dimensional Arrayed Microfluidic Blood–Brain Barrier Model With Integrated Electrical Sensor Array
The blood–brain barrier (BBB) poses a unique challenge to the development of therapeutics against neurological disorders due to its impermeability to most chemical compounds. Most in vitro BBB models have limitations in mimicking in vivo conditions and functions. Here we... Read more
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Enhancement of Intercellular Electrical Synchronization by Conductive Materials in Cardiac Tissue Engineering
Myocardial infarction, due to interruption of blood supply to part of the myocardium, often results in massive loss of cardiomyocytes that are difficult to regenerate intrinsically, which further impairs synchronization of cardiac tissue and causes cardiac arrhythmias. In parallel with... Read more
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Spatial Position Measurement System for Surgical Navigation Using 3-D Image Marker-Based Tracking Tools With Compact Volume
Surgical navigation is critical in assisting surgeons in confirming the spatial positions of surgical instruments and patients in minimally invasive surgery. Traditional tracking systems in surgical navigation have different types, from marker-based optical tracking to magnetic tracking systems. As a... Read more
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New Year Message From the Editor-in-Chief
HAPPY New Year and welcome to 2018! IEEE Transactions on Biomedical Engineering (TBME) remains healthy and strong, with many of the journal’s metrics reaching a historical high heading into the new year. I would like to thank all of you... Read more
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In Vivo Superresolution Imaging of Neuronal Structure in the Mouse Brain
Optical microscopy is an indispensable technique for investigating neuronal morphology and dynamics due to the high spatial and temporal resolution granted by light. However, neuronal morphology and structural changes occur on scales beyond the optical resolution of canonical microscopy technologies.... Read more
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Near-field Inductive Coupling Link To Power a Three-Dimensional Millimeter-Size Antenna for Brain Implantable Medical Devices
Near-field inductive coupling link can establish a reliable power source to a battery-less implantable medical device based on Faraday’s law of induction. In this paper, the design, modeling and experimental verification of an inductive coupling link between an off-body loop... Read more
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Simultaneous Measurement of Multiple Mechanical Properties of Single Cells Using AFM by Indentation and Vibration
Cells, as the elementary units of living organisms, are regulated and governed by genes, biological processes and various microenvironments, and their status reflects the organism’s physiological situation and affects the biological function of the whole body. Moreover, recent studies have... Read more
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Structured Learning for 3D Perivascular Spaces Segmentation Using Vascular Features
Perivascular spaces (PVSs), which are also known as Virchow-Robin spaces, are cerebrospinal fluid (CSF) filled spaces ensheathing small blood vessels as they penetrate the brain parenchyma. The clinical significance of PVSs comes primarily from their tendency to dilate in abnormal... Read more
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Model-Based Estimation of Respiratory Parameters from Capnography, with Application to Diagnosing Obstructive Lung Disease
Capnography is the noninvasive and effort-independent measurement of carbon dioxide concentration in exhaled breath, as a function of time or exhaled volume. Time-based capnography – the focus of this paper – is widely used in ambulances and hospitals. However, its quantitative... Read more
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Electrical Impedance Tomography: Tissue Properties to Image Measures
Interpretation of Electrical Impedance Tomography (EIT) -based measures is complex. This review focuses on clarifying the various processes starting from the tissue electrical properties, through to diagnostic EIT measures, in order to support accurate interpretation of EIT results. The image... Read more
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Software Toolbox for Low-frequency Conductivity and Current Density Imaging using MRI
A software toolbox for low-frequency conductivity and current density imaging using MRI is now available from http://iirc.khu.ac.kr/software.html. This MR-based conductivity imaging (MRCI) toolbox includes Matlab functions for image reconstructions in magnetic resonance electrical impedance tomography (MREIT), diffusion tensor MREIT (DTMREIT), conductivity... Read more
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Electrical Properties Tomography Based on B1 Maps in MRI: Principles, Applications, and Challenges
Electrical properties (EPs), namely conductivity and permittivity, are fundamental properties of materials, describing their capability to transfer electrical current or store energy of the electrical field inside the media. In biological tissue, there is a close relationship between EPs and... Read more
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Quantitative Susceptibility Mapping (QSM) Algorithms: Mathematical Rationale and Computational Implementations
Quantitative susceptibility mapping (QSM) is a noninvasive magnetic resonance imaging (MRI) method that enables quantitative investigation of the tissue magnetic susceptibility, which has been applied to a wide range of biomedical problems. Algorithmically, QSM solves the magnetic field-to-magnetization (tissue susceptibility)... Read more
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Contrast Enhanced Magnetic Resonance Imaging of Gastric Emptying and Motility in Rats
The assessment of gastric emptying and motility in humans and animals typically requires radioactive imaging or invasive measurements. Here, we developed a robust strategy to image and characterize gastric emptying and motility in rats based on contrast-enhanced magnetic resonance imaging... Read more
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Design and Characterization of an Exoskeleton for Perturbing the Knee During Gait
The human knee joint displays a wide range of mechanical behaviors, enabling efficient and robust locomotion under varying conditions. With the rise of active and semi-active knee assistive devices (e.g., prostheses and orthoses), there is a need to quantify the... Read more
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A Subspace Approach to Spectral Quantification for MR Spectroscopic Imaging
Magnetic resonance spectroscopic imaging (MRSI) has been recognized as a potentially powerful tool for label-free in vivo molecular imaging. Spectral quantification is an essential step in deriving quantitative molecular information from experimental MRSI data. However, obtaining accurate spectral estimates is... Read more
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Performance Assessment of a Custom, Portable, and Low-Cost Brain-Computer Interface Platform
Conventional brain-computer interfaces (BCIs) are often expensive, complex to operate, and lack portability, which confines their use to laboratory settings. Portable, inexpensive BCIs can mitigate these problems, but it remains unclear whether their low-cost design compromises their performance. Therefore, we... Read more
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Robust Estimation of Sparse Narrowband Spectra from Neuronal Spiking Data
Characterizing the spectral properties of neuronal responses is an important problem in computational neuroscience as it provides insight into the spectral organization of the underlying functional neural processes. Although spectral analysis techniques are widely used in the analysis of noninvasive... Read more
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Non-Invasive Personalisation of a Cardiac Electrophysiology Model from Body Surface Potential Mapping
We use non-invasive data (body surface potential mapping, BSPM) to personalize the main parameters of a cardiac electrophysiological model for predicting the response to different pacing conditions. First, an efficient forward model is proposed, coupling the Mitchell-Schaeffer transmembrane potential model with... Read more
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Glucose Monitoring in Individuals With Diabetes Using a Long-Term Implanted Sensor/Telemetry System and Model
  Diabetes is a disease that is growing worldwide.  Glucose control is central to all therapies for diabetes and achieving control requires monitoring glucose concentration. We have developed a fully implanted sensor/telemetry system consisting of two electrochemical oxygen sensors, one with... Read more
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Improvement of Pyramidal Tract Side Effect Prediction Using a Data-Driven Method in Subthalamic Stimulation
Subthalamic nucleus deep brain stimulation (STN DBS) is limited by the occurrence of pyramidal tract side effect (PTSE) induced by electrical activation of the pyramidal tract. Predictive models are needed to assist the surgeon during the electrode trajectory pre-planning. The... Read more
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Assessing the Benefits of Drug Delivery by Nanocarriers: A Partico/Pharmacokinetic Framework
Nanocarriers, including solid nanoparticles, liposomes, dendrimers, and polymer micelles, are regarded as promising vehicles for targeted drug delivery, particularly for anticancer agents. Here, an in vivo kinetic framework is introduced to analyze and predict the quantitative advantage of using nanocarriers... Read more
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Prediction of Atherosclerotic Plaque Development in an In Vivo Coronary Arterial Segment Based on a Multilevel Modeling Approach
Coronary heart disease is considered one of the most common causes of death in west societies. The recent years low endothelial shear stress calculated using computational fluid dynamics has been found to be related with atherosclerotic plaque progression. However, until... Read more
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Shape Sensing Techniques for Continuum Robots in Minimally Invasive Surgery: A Survey
Continuum robots provide inherent structural compliance with high dexterity to access the surgical target sites along tortuous anatomical paths under constrained environments, and enable to perform complex and delicate operations through small incisions in minimally invasive surgery (MIS). These advantages... Read more
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High Quality See-Through Surgical Guidance System Using Enhanced 3D Autostereoscopic Augmented Reality
Pre-/intraoperative diagnosis images in minimally invasive surgery can provide necessary guidance for therapy, hand–eye discoordination occurs when guidance information is displayed away from the surgical area. Three-dimensional (3-D) and augmented reality (AR) visualization techniques can provide better judgement and faster... Read more
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A BCI-based Environmental Control System for Patients with Severe Spinal Cord Injuries
An important application of EEG-based brain-computer interface (BCI) is environmental control, which can improve the quality of life for paralyzed patients. However, most of the existing BCI-based environmental control systems were designed for the control of a single device without... Read more
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A Review of In-Body Biotelemetry Devices: Implantables, Ingestibles, and Injectables
Wireless medical devices used to sense physiological parameters (sensors) and/or stimulate the nervous system (stimulators) are becoming increasingly popular. In fact, 27% of Americans already use some sort of wearable device, such as a smart watch that records heart rate... Read more
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Passive BCI in Operational Environments: Insights, Recent Advances and Future Trends
Because of the increasing complexity of automation, the act of monitoring and intervening on the system is becoming very demanding for humans, especially when they are overwhelmed with multiple sources of information on the same perceptual channels, e.g., two visual... Read more
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Automated Compression Device for Viscoelasticity Imaging
Such a device should be lightweight, portable and easy to use for patient studies to capture tissue dynamics under external stress. We present the design of an automated compression device for studying the creep response of materials with tissue-like behaviors.... Read more
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Evaluation of Mobile Phone Performance for Near-Infrared Fluorescence Imaging
Mobile phone technology represents a novel platform for optical imaging that may have significant advantages for telemedicine, global health, emergency response and military medicine applications.  Several clinical optical devices based on mobile phones have been developed, including those performing visible... Read more
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System Integration and In Vivo Testing of a Robot for Ultrasound Guidance and Monitoring During Radiotherapy
Image-guided radiation therapy (IGRT) involves two main steps: (1) planning/simulation using computerized tomography (CT) imaging and (2) fractionated treatment delivery using a linear accelerator (LINAC). These are performed on different days and in different rooms; thus it is necessary to... Read more
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M3BA: A Mobile, Modular, Multimodal Biosignal Acquisition architecture for miniaturized EEG-NIRS based hybrid BCI and monitoring
For the further development of the fields of telemedicine, neurotechnology and Brain-Computer Interfaces (BCI), advances in hybrid multimodal signal acquisition and processing technology are invaluable. Currently, there are no commonly available hybrid devices combining bio-electrical and bio-optical neurophysiological measurements –... Read more
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Simple T Wave Metrics May Better Predict Early Ischemia as Compared to ST Segment
There is a pressing clinical need to identify developing heart attack (infarction) in patients as early as possible. However, current state-of-the-art tools in clinical practice, which are often underpinned by evaluation of elevation of the ST-segment of the 12-lead electrocardiogram,... Read more
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A Subspace Approach to the Structural Decomposition and Identification of Ankle Joint Dynamic Stiffness
The torque developed at a joint in response to a position change arises from both neural and mechanical mechanisms. Torques initiated by mechanical mechanisms, i.e. intrinsic torque, arise from the mechanical properties of the joint and tissues. Torques generated by... Read more
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In-Vivo Electrophysiological Study of Induced Ventricular Tachycardia in Intact Rat Model of Chronic Ischemic Heart Failure
Ventricular tachycardia and ventricular fibrillation are the most common causes of sudden cardiac death in patients with chronic heart failure (CHF). Furthermore, as the next generation of therapeutics for heart failure is developed, it is increasingly important to have reliable... Read more
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Orientation Independent Catheter-Based Characterization of Myocardial Activation
Cardiac electrogram (EGM) signals and electrophysiologic (EP) characteristics derived from them such as amplitude and timing are central to the diagnosis and therapeutic management of arrhythmias. Bipolar EGMs are often used but possess polarity and shape dependence on catheter orientation... Read more
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Spatially Coherent Activation Maps for Electrocardiographic Imaging
Electrocardiographic imaging (ECGi) is an emerging non-invasive technique that computes unipolar electrograms (EGMs) at the epicardial surface from high-density body-surface ECG recordings and torso anatomy. Activation mapping is an important post-processing step that allows the user to make sense of these... Read more
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SVM-Based System for Prediction of Epileptic Seizures From iEEG Signal
This paper describes a data-analytic modeling approach for the prediction of epileptic seizures from intracranial electroencephalogram (iEEG) recording of brain activity. Even though it is widely accepted that statistical characteristics of iEEG signal change prior to seizures, robust seizure prediction... Read more
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Development and Phantom Validation of a 3-D-Ultrasound-Guided System for Targeting MRI-Visible Lesions During Transrectal Prostate Biopsy
Three- (3-) and four-dimensional (4D) endorectal ultrasound are now available from most major ultrasound equipment manufacturers, but have been rarely deployed within prostate biopsy guidance systems despite the benefit of rapid volumetric imaging. The most common type of 3/4D transducers... Read more
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A High-Performance Neural Prosthesis Incorporating Discrete State Selection with Hidden Markov Models
Communication neural prostheses aim to restore efficient communication to people with paralysis and ALS.  These systems record neural signals from the brain and translate them, through a decoder algorithm, into control signals for moving an end effector.  In our study,... Read more
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High-Resolution Electrogastrogram: A Novel, Noninvasive Method for Determining Gastric Slow-Wave Direction and Speed
Although the importance of gastrointestinal (GI) health is increasingly recognized, the lack of a robust, non-invasive system for objective GI electrophysiologic assessment hinders complete understanding of the impact of GI in health and disease.  Novel approaches to diagnose and understand... Read more
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Characterization of a Honeycomb-like Scaffold with Dielectrophoresis-based Patterning for Tissue Engineering
Seeding and patterning of cells with an engineered scaffold is a critical process in artificial tissue construction and regeneration. To date, many engineered scaffolds exhibit simple intrinsic designs, which fail to mimic the geometrical complexity of native tissues. In this... Read more
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Predicting The Influence of Microvascular Structure On Tumour Response to Radiotherapy
Tumour cells are less responsive to radiotherapy in low oxygen environments. Oxygen availability depends on the structure of the supplying microvessel network. Previous studies have used mathematical modelling to predict tumour response to radiotherapy for different network morphologies, but have... Read more
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Stem Cell Plasticity and Niche Dynamics in Cancer Progression
Cancer stem cells are believed to be the sole initiator and driver of tumor growth, given their self-renewal and tissue restoration properties. Their eradication may offer the ultimate in targeted tumor treatment. In this paper we challenge the strict hierarchical... Read more
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Multiscale Modeling of Glioblastoma Suggests that the Partial Disruption of Vessel/Cancer Stem Cell Crosstalk Can Promote Tumor Regression without Increasing Invasiveness
In glioblastoma, the crosstalk between vascular endothelial cells (VECs) and glioma stem cells (GSCs) has been shown to enhance tumor growth. We develop a hybrid continuum-discrete mathematical model and show that the VEC-GSC crosstalk increases both tumor size and GSC... Read more
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The Role of the Tumor Microenvironment in Glioblastoma: A Mathematical Model
Glioblastoma multiforme is one of the deadliest cancers, in part because tumor cells rapidly migrate to the surrounding brain tissue, thereby making the tumor difficult to treat. Microglia are immune cells that, in their normal phenotype M1, kill intracellular micro-organisms... Read more
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Aggregation Effects and Population-Based Dynamics as a Source of Therapy Resistance in Cancer
A flock of starlings responding to the approach of a peregrine illustrates how interactions of an individual with other members of a group may provide advantages against an external threat. Cancer cells, which are often densely clustered together, may use... Read more
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A Biocompatible Near-Infrared 3D Tracking System
A fundamental challenge in soft-tissue surgery is that target tissue moves and deforms, becomes occluded by blood or other tissue, and is difficult to differentiate from surrounding tissue. To overcome these problems, we developed biocompatible near-infrared fluorescent (NIRF) markers with... Read more
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-Omic and Electronic Health Record Big Data Analytics for Precision Medicine
Po-Yen Wu, Chih-Wen Cheng, Chanchala D. Kaddi, Janani Venugopalan, Ryan Hoffman, and May D. Wang, Georgia Institute of Technology and Emory University This article reviews big data analytics that are essential for precision medicine. The advancement of high-throughput -omic assays and computerized health... Read more
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Channel Modeling of Miniaturized Battery-Powered Capacitive Human Body Communication Systems
Jiwoong Park, Harinath Garudadri, and Patrick P. Mercier, University of California San Diego, USA The purpose of this contribution is to estimate the path loss of capacitive human body communication (HBC) systems under practical conditions. Most prior work utilized large, grounded instruments... Read more
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Apnea-Hypopnea Index Prediction Using Electrocardiogram Acquired During Sleep-Onset Period
Da Woon Jung, Su Hwan Hwang, Yu Jin Lee, Do-Un Jeong, and Kwang Suk Park, Seoul National University, Korea With the increase in obesity and the ageing population, obstructive sleep apnea (OSA) has been considered a serious clinical concern. For the... Read more
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4-D Flow Control in Porous Scaffolds: Toward a Next Generation of Bioreactors
The development of stable, functional tissue is a challenge in regenerative medicine. Tissue engineering (TE) approaches that involve seeding cells into pre-determined tissue scaffolds ignore the complex environment where the material properties are spatially inhomogeneous and evolve over time. The... Read more
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