PURPOSE: To describe the abnormal signal intensity seen on MRI of the brain in Wilson disease. MATERIALS AND METHODS: Eight patients (7 male and 1 female, 10 to 33 years of age ) with Wilson disease were studied with a 0.5TMRI system. Patients were divided into symptomatic and asymptomatic groups, and MR imaging was compared withclinical data. RESULTS: In 93 lesions, signal intensity was abnormal ; there was involvement of the pallidus(24lesions, 26%), the midbrain (20, 22%), the pons(14, 15%), the putamen (13, 14%), the thalamus(6, 7%), thepituitary gland (4, 4%), the caudate nuclei (4, 4%), the internal capsule (4, 4%), and the dentate nucleus (4,4%). In the putamen, all lesions but one were bilateral, and there was symmetric distribution. The four patientswith neurologic symptoms had 69 lesions and the remaining four without such symptoms had 24 lesions. OnT2-weighted images, high signal intensity was seen in all lesions but two, and on T1-weighted images, this wasseen in 24 lesions. All lesions of the pituitary gland showed high signal intensity on T1-weighted images.CONCLUSION: Lesions were frequently seen in the globus pallidus, midbrain, pons and putamen, and were more commonin patients with neurologic symptoms.