Apparent diffusion coefficient restriction in the white matter: Going beyond acute brain territorial ischemia

Abstract

Background Reduction of apparent diffusion coefficient (ADC) values in white matter is not always ischaemic in nature. Methods We retrospectively analysed our MRI records featuring reduced ADC values in the centrum semiovale without grey matter involvement or significant vasogenic oedema. Results Several conditions showed the aforementioned MR findings: moose-horn lesions on coronal images in X-linked Charcot-Marie-Tooth disease; small fronto-parietal lesions in enkes disease; marked signal abnormalities in the myelinised regions in the acute neonatal form of maple syrup urine disease; strip-like involvement of the corpus callosum in glutaric aciduria type 1; persistent periventricular parietooccipital abnormalities in phenylketonuria; diffuse signal abnormalities with necrotic evolution in global cerebral anoxia or after heroin vapour inhalation; almost completely reversible symmetric fronto-parietal lesions in methotrexate neurotoxicity; chain-like lesions in watershed ischaemia; splenium involvement that normalises in reversible splenial lesions or leads to gliosis in diffuse axonal injury. Conclusion Neuroradiologists must be familiar with these features, thereby preventing misdiagnosis and inappropriate management. © European Society of Radiology 2011.