Laminar cortical damage in multiple sclerosis

This scientific commentary refers to ‘A gradient in cortical pathology in multiple sclerosis by in vivo quantitative 7 T imaging’, by Mainero et al. (doi:10.1093/brain/awv011). Multiple sclerosis is widely regarded as an archetypical white matter disease. The early histopathological descriptions of grey matter involvement resurfaced only when MRI studies reiterated the frequent occurrence of cortical lesions in multiple sclerosis (Kidd et al. , 1999). In fact, cortical demyelination is seen in very few other CNS diseases (Lassmann, 2012) and the occurrence of juxtacortical lesions is one of the main differentiating features for multiple sclerosis (Barkhof et al. , 1997). Comparison of MRI and histopathology has been a humbling experience for radiologists, but also a learning opportunity for pathologists (Geurts and Barkhof, 2008). The use of sensitive immunohistochemical staining techniques (against major myelin proteins) has provided a wealth of data on the type and extent of cortical involvement in (progressive) multiple sclerosis. Subpial lesions in particular can be extensive (Kutzelnigg et al. , 2005) and have triggered debate as to the underlying causal factors, which are believed by some to be found in the CSF or to be related to inflammation in overlying meninges.One of the ‘grand challenges’ in imaging of cortical pathology is the in vivo detection of the most dominant cortical lesion type, the subpial lesion, by means of …