PURPOSE: To observe MR findings of vascular abnormality in Sturge-Weber syndrome and to determine the value of MRI in diagnosis. MATERIALS AND METHODS: Ten patients with Sturge-Weber syndrome (age : 3 months-32 years)were evaluated by MR imaging ; in six and four cases, respectively, the results were correlated with those of CT and angiography. We retrospectively analysed changes in the cortical vein and deep venous system, including the medullary and subependymal vein, as well as an largement of the choroid plexus, leptomeningeal enhancement, and changes in diploic space. RESULTS: In all cases except one, in which non-contrast enhanced study had been performed, varying degrees of leptomeningeal enhancement were seen. In nine cases the cortical vein became smaller; enlargement of the choroid plexus was seen in eight cases, change in the diploic space in seven (including three in which there was angiomatous involvement), and enlargement of the deep venous system in seven. In younger patients, collateral pathways were less developed and leptomeningeal angiomatous changes were more pronounced than in those who were older. CONCLUSION: MRI is a useful modality for the evaluationn of vascular changes in Sturge-Weber syndrome. These changes vary according to a patient's age and the duration of the disease.