a-magnetic-resonance-imaging-based-computational-protocol-for

A Magnetic Resonance Imaging-based Computational Protocol for Analysis of Plaque Morphology and Hemodynamics in Patients with Carotid Artery Stenosis

Current assessment and management of internal carotid artery (ICA) stenosis is based on the estimation of percentage stenosis via duplex ultrasound (DUS) ...

University of Michigan

The purpose of this study was to assess the quality of clinical brain imaging in healthy subjects and patients on an FDA-approved commercial 0.55 T MRI scanner, and to provide information about the feasibility of using this scanner in a clinical workflow. In this IRB-approved study, brain examinations on the scanner were prospectively performed in 10 healthy subjects (February-April 2022) and retrospectively derived from 44 patients (February-July 2022). Images collected using the following pulse sequences were available for assessment: axial DWI (diffusion-weighted imaging), apparent diffusion coefficient maps, 2D axial fluid-attenuated inversion recovery images, axial susceptibility-weighted images (both magnitude and phase), sagittal T-weighted (T1w) Sampling Perfection with Application Optimized Contrast images, sagittal T1w MPRAGE (magnetization prepared rapid gradient echo) with contrast enhancement, axial T1w turbo spin echo (TSE) with and without contrast enhancement, and axial T-weighted TSE. Two readers retrospectively and independently evaluated image quality and specific anatomical features in a blinded fashion on a four-point Likert scale, with a score of 1 being unacceptable and 4 being excellent, and determined the ability to answer the clinical question in patients. For each category of image sequences, the mean, standard deviation, and percentage of unacceptable quality images (<2) were calculated. Acceptable (rating ≥ 2) image quality was achieved at 0.55 T in all sequences for patients and 85% of the sequences for healthy subjects. Radiologists were able to answer the clinical question in all patients scanned. In total, 50% of the sequences used in patients and about 60% of the sequences used in healthy subjects exhibited good (rating ≥ 3) image quality. Based on these findings, we conclude that diagnostic quality clinical brain images can be successfully collected on this commercial 0.55 T scanner, indicating that the routine brain imaging protocol may be deployed on this system in the clinical workflow.

Quality assessment of routine brain imaging at 0.55 T: initial experience in a clinical workflow.

This study aims to assess the quality of abdominal MR images acquired on a commercial 0.55T scanner and compare these images with those acquired on conventional 1.5T/3T scanners in both healthy subjects and patients.

Abdominal MRI on a Commercial 0.55T System: Initial Evaluation and Comparison to Higher Field Strengths.

To compare image quality, assess inter-reader variability, and evaluate the diagnostic efficacy of routine clinical lumbar spine sequences at 0.55T compared with those collected at 1.5/3T to assess common spine pathology.

Comparison of image quality and diagnostic efficacy of routine clinical lumbar spine imaging at 0.55T and 1.5/3T.

To compare the image quality of routine clinical brain MRI sequences at 0.55 T and 1.5/3T and toexplore changes in radiologists' ratings of 0.55 T images over time.

Retrospective comparison of routine brain MRI scans in patients at 0.55 T and 1.5/3T.

MRI for diagnosis and assessment of neurologic conditions is most commonly performed on 1.5- and 3.0-T systems. Recently, motivation to increase accessibility to MRI, coupled with advances in software and hardware, has sparked renewed interest in MRI systems with magnetic field strengths ranging from 0.064 T to 1.0 T. The authors describe the protocols and indications for neuroradiologic imaging performed on a modern whole-body, mid-field-strength 0.55-T MRI system. The overall image quality of routine clinical brain and spinal imaging at 0.55 T is lower than that at 1.5 T but still diagnostic for many routine indications. The intrinsic benefits of using a lower main magnetic field strength may be leveraged for imaging intracranial and spinal hardware due to diminished susceptibility artifacts and pose new opportunities for increased MRI safety. In addition, the imaging of structures that are near bone, such as the internal auditory canal, may represent an opportunity for additional use of MRI with lower magnetic field strengths due to reduced magnetic susceptibility differences and greater field homogeneity. However, lower main magnetic field strength limits the use of frequency-selective fat saturation and introduces challenges for Dixon-based fat suppression. The limitations of one specific 0.55-T system include acceleration artifacts and insufficient signal intensity of dynamic contrast-enhanced susceptibility-weighted perfusion imaging, which precluded the evaluation of multiple sclerosis and primary brain tumors. Investigations of ongoing technical developments of 0.55-T MRI include exploring sequence structures that are particularly advantageous at lower field strengths, such as those in balanced steady-state free-precession and single-shot fast spin-echo MRI, which are being used in functional and fetal MRI. Deep learning algorithms are also being used to improve image quality while maintaining or reducing imaging times. RSNA, 2025 Supplemental material is available for this article. See the invited commentary by Pai and Jabehdar Maralani in this issue.

Routine and Advanced Neurologic Imaging at 0.55-T MRI: Opportunities and Challenges.

Low-field MRI has been assumed to be implant-friendly based on limited studies. However, radiofrequency (RF)-induced heating due to an implant is a complex resonance phenomenon, highly dependent on the implant's configurations and applied RF frequencies. This study aims to evaluate the RF heating of deep brain stimulation (DBS) implants during MRI at low field strengths compared with higher-field 1.5T MRI.

Comparative study of radiofrequency heating in deep brain stimulation devices during MRI at 1.5 T and 0.55 T: Challenging the assumption of safety at low field strengths.

Article	Year
Quality assessment of routine brain imaging at 0.55 T: initial experience in a clinical workflow. NMR in biomedicine\| PubMed ID: 37654047	2024
Abdominal MRI on a Commercial 0.55T System: Initial Evaluation and Comparison to Higher Field Strengths. Academic radiology\| PubMed ID: 38320946	2024
Comparison of image quality and diagnostic efficacy of routine clinical lumbar spine imaging at 0.55T and 1.5/3T. European journal of radiology\| PubMed ID: 38490129	2024
Retrospective comparison of routine brain MRI scans in patients at 0.55 T and 1.5/3T. European journal of radiology\| PubMed ID: 39919700	2025
Routine and Advanced Neurologic Imaging at 0.55-T MRI: Opportunities and Challenges. Radiographics : a review publication of the Radiological Society of North America, Inc\| PubMed ID: 39946265	2025
Comparative study of radiofrequency heating in deep brain stimulation devices during MRI at 1.5 T and 0.55 T: Challenging the assumption of safety at low field strengths. Magnetic resonance in medicine\| PubMed ID: 40294129	2025

Jacob Richardson

Biography

JoVE Journal Publications

Other Publications