Spatial clustering of hemorrhages in probable cerebral amyloid angiopathy.

Cerebral amyloid angiopathy (CAA) is a common cause of symptomatic intracerebral hemorrhage (ICH), as well as small asymptomatic hemorrhage in the elderly. We used gradient-echo MRI to analyze spatial distribution of 321 hemorrhages in 59 patients with probable CAA-related ICH. Hemorrhagic lesions were found preferentially in the temporal (ratio of actual to expected hemorrhages = 1.37) and occipital lobes (ratio = 1.45, p < 0.0001). Within individuals, hemorrhages tended to cluster, regardless of lobe (p < 0.0001). Among subjects followed prospectively for recurrence, clustering of new symptomatic and asymptomatic hemorrhages was observed. These data suggest that regional differences within the brain play a role in the development of CAA-related hemorrhage.