We examined the serial CTs and clinical courses of five patients with neuro-Behçet's disease and reviewed ten previously reported cases, all with focal CT abnormalities. The CT lesions were in the brainstem (8 patients), basal ganglia (7), thalamus (4), or hemispheric white matter (7). Of the 13 patients who received contrast, nine had lesions that showed enhancement. In five, lesions were visualized with contrast that were not apparent without it. The CT lesions were usually accompanied by corresponding clinical deficits, although in some patients deficits were more extensive than the CT predicted. In nine patients, contrast enhancement decreased or disappeared over days to weeks, often with associated clinical improvement. In eight patients followed serially, CT abnormalities resolved completely or substantially. Based on these cases, we conclude that (1) CT abnormalities of gray and white matter occur commonly in neuro-Behçet's disease with focal deficits, and help support the diagnosis; (2) CT abnormalities, particularly contrast enhancement, correlate well with the activity of parenchymal disease; and (3) the concomitant improvement of clinical and CT abnormalities with resolution of contrast enhancement suggests that partially reversible inflammatory changes associated with breakdown of the blood-brain barrier may produce some of the neurologic and radiographic deficits in this illness.