Multiple sclerosis is considered to be caused by deterioration of white matter in the brain, but a meta-analysis of recent studies concluded that grey matter atrophy could also be a factor.
Multiple sclerosis (MS) could be a disease of the brain’s grey matter (GM), and not white matter (WM) as previously thought, according to a meta-analysis of detection techniques published in ActaNeurologicaScandinavica.
It was previously accepted that MS was a disease primarily infecting the brain’s WM. However, GM has now been linked to the disease as well, as it is a factor in memory impairment, attention, and information processing speed. GM atrophy, the deterioration of brain matter, is now believed to play a role in both clinical and cognitive deterioration.
Investigators explored the restraints of MRI methods to visualize GM pathology. As many as 5 times more GM lesions can be detected with the implementation of double inversion recovery (DIR), yet this technique is still imperfect due to sensitivity limits.
GM volumes can be compared using voxel-based morphometry, which measures segmentations of conventional spin-echo MR images. It allows for fully-automated comparisons of multiple subject scans. Detection of cortical lesions has been greatly improved by ultra-high-field MRI, but these techniques are not widely available.
Another flaw in studying MS, the authors note, was that in several studies brain atrophy and GM atrophy is measured without any control on healthy subjects for comparison.
“The somewhat conflicting findings between GM atrophy and physical disability progression measured by EDSS [the Expanded Disability Status Scale] and MSFC [Multiple Sclerosis Functional Composite] may also reflect the general issue that robust standardized and quantified evaluation of the MS patients is still lacking,” the authors wrote. “The weaknesses of both EDSS and MSFC are widely known and taken into account, but, on the other hand, it is the most reliable parameters in general use for clinicians.”
While they recommend further investigations, they note that GM atrophy has maybe even a greater degree of predictive value over WM lesions and atrophy.