A heterogeneous group of disorders that includes sporadic and familial forms, characterized clinically by cerebral ischemia (see BRAIN ISCHEMIA); CEREBRAL INFARCTION; and CEREBRAL HEMORRHAGE. Pathologically the condition is marked by the deposition of AMYLOID in the walls of small blood vessels in the cerebral cortex and meninges. The sporadic form is associated with lobar cerebral hemorrhage in the elderly and ALZHEIMER DISEASE. (From Neuropathol Appl Neurobiol 1996 Jun;22(3):216-227; Adams et al., Principles of Neurology, 6th ed, p852).