Granulomatous angiitis is a pathologically distinct central nervous system segmental vasculitis of unknown etiology and pathogenesis which may be indirectly related to herpes zoster infections. The condition primarily affects adults and presents with nonspecific, unexplained progressive neurological dysfunction. The cerebrospinal fluid is often under increased pressure and contains excess protein and white cells, mostly lymphocytes. The necrotizing vasculitis primarily affects the small intracranial arteries and veins and alters vascular permeability, ind,cing cerebral edema. Angiography demonstrates segmental, diffuse, distal vascular irregularity and narrowing, while computed tomography shows poorly defined, diffuse, non-contrast-enhancing low density areas with or without mass effect. In the approprite clinical setting, the angiographic and CT findings should be highly suggestive. The possibility of efficious therapeutic intervention makes early diagnosis important. CT can also be used to monitor therapeutic response.