Ultra-High-Field MRI in the Diagnosis and Management of Gliomas: A Systematic Review

Abstract

Importance:Gliomas, tumors of the central nervous system, are classically diagnosed through invasive surgical biopsy and subsequent histopathological study. Innovations in ultra-high field (UHF) imaging, namely 7-Tesla magnetic resonance imaging (7T MRI) are advancing preoperative tumor grading, visualization of intratumoral structures, and appreciation of small brain structures and lesions.ObjectiveSummarize current innovative uses of UHF imaging techniques in glioma diagnostics and treatment.MethodsA systematic review in accordance with PRISMA guidelines was performed utilizing PubMed. Case reports and series, observational clinical trials, and randomized clinical trials written in English were included. After removing unrelated studies and those with non-human subjects, only those related to 7T MRI were independently reviewed and summarized for data extraction. Some preclinical animal models are briefly described to demonstrate future usages of ultra-high-field imaging.ResultsWe reviewed 46 studies (43 human and 3 animal models) which reported clinical usages of UHF MRI in the diagnosis and management of gliomas. Current literature generally supports greater resolution imaging from 7T compared to 1.5T or 3T MRI, improving visualization of cerebral microbleeds and white and gray matter, and providing more precise localization for radiotherapy targeting. Additionally, studies found that diffusion or susceptibility-weighted imaging techniques applied to 7T MRI, may be used to predict tumor grade, reveal intratumoral structures such as neovasculature and microstructures like axons, and indicate isocitrate dehydrogenase 1 mutation status in preoperative imaging. Similarly, newer imaging techniques such as magnetic resonance spectroscopy and chemical exchange saturation transfer imaging can be performed on 7T MRI to predict tumor grading and treatment efficacy. Geometrical distortion, a known challenge of 7T MRI, was at a tolerable level in all included studies.ConclusionUHF imaging has the potential to preoperatively and non-invasively grade gliomas, provide precise therapy target areas, and visualize lesions not seen on conventional MRI.

Neurosurgical Implant Safety in 7 T MRI: A Scoping Review

“…Ultra-high-field MRI of the brain and spine has several clinical applications, including neoplasm, neurodegenerative disease, epilepsy, and spinal cord perfusion mapping. 1,[33][34][35] While the number of UHF MRI scanners is rapidly expanding in the United States and globally, 7 T scans may not be routinely performed, in part due to their similar level of reimbursement despite higher cost of equipment. A 7 T MRI is approved for clinical use by the FDA in extremities and the brain, but research must continue to demonstrate significantly Torque rated on a qualitative scale 0 (no torque) to 4 (very strong torque); 0, 1 (mild or low torque), and 2 (moderate torque) were considered acceptable.…”

“…Ultra‐high‐field MRI of the brain and spine has several clinical applications, including neoplasm, neurodegenerative disease, epilepsy, and spinal cord perfusion mapping 1,33–35 . While the number of UHF MRI scanners is rapidly expanding in the United States and globally, 7 T scans may not be routinely performed, in part due to their similar level of reimbursement despite higher cost of equipment.…”

“…2,3 Additionally, 7 T MRI offers an increased signal-to-noise ratio enabling greater spatial resolution, spectral resolution, and enhanced molecular data compared to 3 T scanners. 1 Ultra-high-field (UHF) MRI (7 T or greater) is becoming increasingly common in research and clinical settings.…”

“…The use of 7 Tesla (T) magnetic resonance imaging (MRI) of the brain has increased due to its ability to noninvasively characterize neoplasms 1 and differentiate cerebral microbleeds and vasculature 2,3 . Additionally, 7 T MRI offers an increased signal‐to‐noise ratio enabling greater spatial resolution, spectral resolution, and enhanced molecular data compared to 3 T scanners 1 . Ultra‐high‐field (UHF) MRI (7 T or greater) is becoming increasingly common in research and clinical settings.…”

Preclinical magnetic resonance imaging and spectroscopy in the fields of radiological technology, medical physics, and radiology

“…Recently, several imaging modalities, including magnetic resonance imaging (MRI) [ 1 – 3 ], radiography, computed tomography (CT) [ 4 – 9 ], positron emission tomography (PET) [ 10 , 11 ], single-photon emission computed tomography (SPECT) [ 12 , 13 ], electron microscopy, autoradiography, optical imaging, and ultrasound (US) [ 14 – 17 ], have been applied in biomedical, genetic, toxicologic, cancer, cardiology, and pharmacological research worldwide. These are all noninvasive imaging modalities with proven clinical applications that have been extended to in vivo and ex vivo research specimens as small as mice, rats, and marmosets [ 9 , 18 , 19 ].…”