Nontraumatic intracranial hemorrhage.

Nontraumatic (or spontaneous) intracranial hemorrhage most commonly involves the brain parenchyma and subarachnoid space. This entity accounts for at least 10% of strokes and is a leading cause of death and disability in adults. Important causes of spontaneous intracranial hemorrhage include hypertension, cerebral amyloid angiopathy, aneurysms, vascular malformations, and hemorrhagic infarcts (both venous and arterial). Imaging findings in common and less common causes of spontaneous intracranial hemorrhage are reviewed.