Cortical lesions in multiple sclerosis

Although previous studies have shown that the lesions of multiple sclerosis may involve the cerebral cortex, there is little published research on the prevalence and distribution of such lesions. Using neuropathological techn iques and MRT, a series of studies has been undertaken in order to assess t his, in particular to identify their relationship to cortical veins. A seri al MRI study showed that the use of gadolinium proffered an increase in cor tical lesion detection of 140% and showed that 26% of active lesions arose within or adjacent to the cortex. In a post-mortem study, MRI under-reporte d lesions subsequently analysed neuropathologically, particularly those ari sing within the cortex. In a further 12 cases examined, 478 cortical lesion s were identified, of which 372 also involved the subcortical white matter. Seven different lesion types were identified; the majority arose within th e territory of the principal cortical veins, whilst the remaining quarter a rose within the territory of the small branch or superficial veins, Small c ortical lesions are common in multiple sclerosis and are under-reported by MRI, Investigation of the cortical venous supply shows how such lesions may arise, and why the majority also involve the underlying white matter.