CNS changes in three cases of neuro-Behçet's disease were observed by computed tomography (CT), magnetic resonance (MR) and single photon emission computed tomography (SPECT). The present study illustrates the reversibility of lesions in the brain stem with MR, while CT failed to show any abnormal findings in the region of the disease. We conclude that MR is a quite useful method to detect lesions in the brain stem and to evaluate the effects of treatment in neuro-Behçet's disease. SPECT is also an important method for the evaluation of dementia recognized in neuro-Behçet's disease.