CT scans of 11 patients with proved white-matter disease were reviewed and divided into three categories. The demyelinating (secondary) and diffuse sclerosis groups frequently exhibited abnormal intravenous enhancement and mass shift. This made differentiation from inflammatory and neoplastic processes difficult. In the dysmyelinating disorders, pathologically noted diffuse loss of white matter and absence of inflammatory response appeared on the scans as areas of diffuse and decreased density in the centrum semiovale. There was no evidence of abnormal contrast enhancement.