Follow-up magnetic resonance imaging (MRI) and computed tomography (CT) examinations were performed on five patients with Wilson's disease at intervals from 6 to 29 months. We studied the clinical correlation with MRI and CT, and whether the examination of MRI and CT could be useful for evaluation of the therapeutic effect. Positron emission tomography (PET) was also carried out on 4 cases except for an asymptomatic case (patient 2, sister of patient 1). Close relationship has been observed by MRI between dystonia and the lesion of the lenticular nuclei, abnormality of smooth pursuit eye movements and the brain stem lesion, and severe dysarthria/dysphagia and the lesion of the caudate and lenticular nuclei, respectively. In patient 4, repeated MRI of an interval of 18 months demonstrated decrease of the abnormal high signal in the lateral part of the putamen on T2-weighted image in accordance with marked improvement of clinical manifestations. In patient 3, who had severe dystonia of the extremities and trunk, T2-weighted image showed high signals in the lenticular nuclei. Marked decrease of the high signal in the lenticular nuclei was observed by MRI in this patient after 29 months, when her neurological manifestations were markedly improved. Patient 5 with severe cerebellar signs disclosed abnormal signals in the middle cerebellar peduncles, brain stem and dentate nuclei in addition to low signals in the caudate and lenticular nuclei, and high signals in the lateral part of the putamen on T2-sequence.(ABSTRACT TRUNCATED AT 250 WORDS)