Clinical Research for the Use of 7 T Magnetic Resonance Imaging for Spinal Pathologies: a Scoping Review

Magnetic resonance imaging (MRI) at 7 T (7T) offers higher signal-to-noise ratio and improved spatial resolution compared to lower magnetic field strengths such as 1.5T and 3T, which may improve lesion detection and anatomical visualization for spinal cord pathology. This review summarizes current techniques and achievements in 7T spinal imaging and outlines associated technical barriers and future directions.

A scoping review in accordance with PRISMA extension for scoping reviews guidelines was performed utilizing PubMed, Scopus, and Web of Science. Only studies related to 7T MRI of human subjects were included, after removing unrelated studies and those of non-human subjects.

Twenty-nine studies were included. Current literature supports 7T's superior resolution and signal-to-noise ratio in comparison to 1.5T and 3T MRI. These studies reported improved lesion detection and staging in multiple sclerosis (MS), spinal cord injury (SCI), and amyotrophic lateral sclerosis (ALS); however, the implications of results are limited by small sample sizes, technical heterogeneity, and inconsistent outcome measures. Additionally, the use of 7T spinal imaging remains limited by radiofrequency coil design, susceptibility artifacts, physiological noise, lack of FDA-clearance for spinal indications, and an absence of standardized imaging protocols. Future research aims to address these limitations.

Spinal cord imaging at 7T is challenging due to technical constraints and higher susceptibility to artifacts as a result of physiological noise (respiration, swallowing, and bulk movement). However, early studies' results using 7T imaging support improved ability, compared to 3T, to provide enhanced visualization of fine anatomical structures, such as nerve roots, and to improve spinal cord lesion detection.