magnetic resonance imaging

MRI-Guided Cardiac RF Ablation for Comparing MRI Characteristics of Acute Lesions and Associated Electrophysiologic Voltage Reductions

MRI-Guided Cardiac RF Ablation for Comparing MRI Characteristics of Acute Lesions and Associated Electrophysiologic Voltage Reductions 2560 1427 IEEE Transactions on Biomedical Engineering (TBME)
This study characterizes permanent and transient injury caused by cardiac RF ablation in a preclinical model. Native-contrast MRI features of ablation were investigated in relation to catheter-based electrophysiologic (EP) signals inherently co-registered within the same coordinate frame, and histologically validated. Specifically, we show that bipolar voltage was reduced in the presence of both the permanent T1-derived RF lesion and transient T2-derived edema. These results suggest that these regions are distinct in native-contrast MRI, but not differentiable using bipolar voltage. Intraprocedural MRI visualization distinguishing transient and permanent injury could guide creation of more complete durable RF ablations, reducing arrhythmia recurrence. read more

Simultaneous localized brain mild hyperthermia and blood-brain barrier opening via feedback-controlled transcranial MR-guided focused ultrasound and microbubbles

Simultaneous localized brain mild hyperthermia and blood-brain barrier opening via feedback-controlled transcranial MR-guided focused ultrasound and microbubbles IEEE Transactions on Biomedical Engineering (TBME)
We present a synergistic focused ultrasound-based brain drug delivery method for both spatiotemporally precise transcranial mild hyperthermia and simultaneous localized blood-brain barrier (BBB) opening. We demonstrated that with the presence of microbubbles, transcranial MR-guided focused ultrasound mild hyperthermia can be achieved at significantly reduced powers and prolonged BBB opening can be simultaneously achieved with hyperthermia sonications in a rodent model. No structural abnormality, edema, hemorrhage, or acute microglial activation was observed in the target region via MR imaging and histology. This study provides a new strategy for enhanced drug delivery in brain tissues with a high clinical translation potential. read more

Learning Multiparametric Biomarkers for Assessing MR-Guided Focused Ultrasound Treatment of Malignant Tumors

Author(s): Blake Zimmerman, Sara Johnson, Henrik Odéen, Jill Shea, Markus D. Foote, Nicole Winkler, Sarang Joshi, Allison Payne
Learning Multiparametric Biomarkers for Assessing MR-Guided Focused Ultrasound Treatment of Malignant Tumors 170 177 IEEE Transactions on Biomedical Engineering (TBME)
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

A breast-specific MR guided focused ultrasound platform and treatment protocol: first-in-human technical evaluation

Author(s): Allison Payne, Robb Merrill, Emilee Minalga, J. Rock Hadley, Henrik Odéen, Lorne W. Hofstetter, Sara Johnson, Christine Tunon de Lara, Sophie Auriol, Stephanié Recco, Erik Dumont, Dennis L. Parker, Jean Palussiere
A breast-specific MR guided focused ultrasound platform and treatment protocol: first-in-human technical evaluation 176 170 IEEE Transactions on Biomedical Engineering (TBME)
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

Reference-Based Integral MR-EPT: Simulation and Experiment Studies at 9.4T MRI

Author(s): Lei Guo, Jin Jin, Mingyan Li, Yaohui Wang, Chun yi Liu, Feng Liu, Stuart Crozier
Reference-Based Integral MR-EPT: Simulation and Experiment Studies at 9.4T MRI 170 177 IEEE Transactions on Biomedical Engineering (TBME)

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…

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Patient-Specific Computational Simulations of Hyperpolarized 3He MRI Ventilation Defects in Healthy and Asthmatic Subjects

Patient-Specific Computational Simulations of Hyperpolarized 3He MRI Ventilation Defects in Healthy and Asthmatic Subjects

Author(s): Jessica M. Oakes, David G. Mummy, Kamran Poorbahrami, Wei Zha, Sean Fain
Patient-Specific Computational Simulations of Hyperpolarized 3He MRI Ventilation Defects in Healthy and Asthmatic Subjects 170 125 IEEE Transactions on Biomedical Engineering (TBME)

     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…

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Contrast Enhanced Magnetic Resonance Imaging of Gastric Emptying and Motility in Rats

Electrical Properties Tomography Based on B1 Maps in MRI: Principles, Applications, and Challenges

Author(s): Jiaen Liu, Yicun Wang, Ulrich Katscher, Bin He
Electrical Properties Tomography Based on B1 Maps in MRI: Principles, Applications, and Challenges 170 177 IEEE Transactions on Biomedical Engineering (TBME)

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…

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Contrast Enhanced Magnetic Resonance Imaging of Gastric Emptying and Motility in Rats

Contrast Enhanced Magnetic Resonance Imaging of Gastric Emptying and Motility in Rats

Author(s): Kun-Han Lu, Jiayue Cao, Steven Oleson, Terry L. Powley, Zhongming Liu
Contrast Enhanced Magnetic Resonance Imaging of Gastric Emptying and Motility in Rats 170 177 IEEE Transactions on Biomedical Engineering (TBME)

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…

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Fast Electromagnetic Analysis of MRI Transmit RF Coils based on Accelerated Integral Equation Methods

Fast Electromagnetic Analysis of MRI Transmit RF Coils based on Accelerated Integral Equation Methods

Author(s): Jorge Fernandez Villena, Athanasios G. Polimeridis, Yigitcan Eryaman, Elfar Adalsteinsson, Lawrence L. Wald, Jacob K. White, Luca Daniel
Fast Electromagnetic Analysis of MRI Transmit RF Coils based on Accelerated Integral Equation Methods 170 177 IEEE Transactions on Biomedical Engineering (TBME)

Jorge Fernández Villena, Athanasios G. Polimeridis, Yigitcan Eryaman, Elfar Adalsteinsson, Lawrence L. Wald, Jacob K. White, and Luca Daniel, Massachusetts Institute of Technology, University of Minnesota, Massachusetts General Hospital, Harvard-MIT Division of Health Sciences…

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Electric Field Model of Transcranial Electric Stimulation in Nonhuman Primates: Correspondence to Individual Motor Threshold

Author(s): Won Hee Lee, Sarah H. Lisanby, Andrew F. Laine, Angel V. Peterchev
Electric Field Model of Transcranial Electric Stimulation in Nonhuman Primates: Correspondence to Individual Motor Threshold 170 177 IEEE Transactions on Biomedical Engineering (TBME)

This paper describes a pipeline for realistic head models of nonhuman primates for simulations of noninvasive brain stimulation, and uses these models together with empirical threshold measurements to demonstrate that…

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