Increased cortical grey matter lesion detection in multiple sclerosis with 7 T MRI: a post-mortem verification study

Area of Science:

• Neuroimaging
• Neuropathology
• Multiple Sclerosis Research

Background:

• Cortical grey matter pathology is increasingly recognized in multiple sclerosis (MS).
• Standard 3 Tesla (T) magnetic resonance imaging (MRI) often fails to detect cortical lesions.
• Ultra-high field MRI, such as 7T, shows promise for improved lesion detection in vivo.

Purpose of the Study:

• To systematically compare the sensitivity of 7T versus 3T MRI pulse sequences for detecting cortical MS lesions.
• To validate MRI findings against direct histopathological examination.

Main Methods:

• Coronally cut brain sections from 19 MS patients and 4 controls were scanned using 3T and 7T MRI.
• Standard MRI pulse sequences (T1w, T2w, FLAIR, DTI, T2*) were employed.
• Histopathology was performed using proteolipid protein staining; MRI and histology were matched for comparison.

Main Results:

• 7T MRI detected significantly more cortical lesions than 3T MRI across all sequences.
• Fluid Attenuated Inversion Recovery (FLAIR) at 7T detected 225% more lesions than at 3T (p < 0.05).
• 7T T2* detected 200% more lesions than 3T T2* (p < 0.05); sensitivity varied by lesion type at 7T.

Conclusions:

• Ultra-high field 7T MRI more than doubles the detection of cortical MS lesions compared to 3T MRI.
• Despite advancements, 7T MRI still underestimates the full extent of subpial cortical pathology in MS.