Primary angiitis of the central nervous system and silent cortical hemorrhages.

Primary angiitis of the CNS is histopathologically characterized by ischemic lesions and small petechial hemorrhages. Unlike CT or conventional MR imaging, gradient-echo MR imaging depicts these chronic petechial hemorrhages. We herein report the case of biopsy-proved primary angiitis of the CNS in a 42-year-old man; whom gradient-echo MR imaging revealed multiple petechial hemorrhages in the cortical-subcortical brain regions. The identification of petechial hemorrhages by gradient-echo MR imaging promises to be a valuable surrogate marker supporting the diagnosis of primary angiitis of the CNS.