High-resolution phased-array MRI of the human brain at 7 tesla: initial experience in multiple sclerosis patients

Recent advancement for magnetic resonance imaging (MRI) involves the incorporation of higher-field strengths. Although imagers with higher magnetic field strengths were developed and tested in research labs, the direct application to patient MR studies have been extremely limited. Imaging at 7 Tesla (7T) affords advantages in signal-to-noise ratio and image contrast and resolution; however, these benefits can only be realized if the correct coils exist to capture the images. The objective of this study was to develop optimized high-resolution 7T MRI techniques using high sensitivity, specialized phased-array coils, for improved gray matter (GM) and white matter differentiation, in an effort to improve visualization of multiple sclerosis (MS) lesions in vivo. Twenty-three subjects were enrolled in this preliminary study, 17 with clinically definite MS (11 females, 6 males; mean age 43.4 years; range 22-64 years) and 6 healthy controls (2 females, 4 males; mean age 39.0 years; range 27-67 years). MR imaging of MS patients at 7T was demonstrated to be safe, well tolerated, and provided high-resolution anatomical images allowing visualization of structural abnormalities localized near or within the cortical layers. Clear involvement of the GM was observed with improved morphological detail in comparison to imaging at lower-field strength.