The commonly discussed MS plaques are within the white matter (WM) of the brain and are called (WM) lesions and can be seen on regular MRIs.
Interestingly, a different type of lesion has been described in the cortex of MS patients, and a significant number of MS patients has these cortical lesions.
The presence of cortical MS lesions has been confirmed in several pathological and imaging studies and has been recognized as an important component of MS.
Despite resembling areas of WM demyelination, cortical lesions differ substantially from WM lesions in terms of degree of inflammation, and different cortical lesion types have been described.
Cortical lesions are commonly detected in the cingulate gyrus, frontal and temporal lobes, insular cortex and cerebellum and have a high correlation with cognitive and physical disability.
A few studies indicate that cortical inflammation might already be present at the early stages of MS.
It is currently difficult to capture these lesions with MRIs techniques used in the regular clinical setting, but advanced imaging techniques (e.g. MRIs with higher magnet, 7T MRI) can detected these lesions.
It will be important to consider these lesions in the future in all patients, and to correlate them with specific symptoms, and to assess if treatment is working on this lesion type.
Ulrike Kauzner MD PhD