Computed tomographic diagnosis of ruptured giant posterior cerebral artery aneurysms.

Ruptured giant posterior cerebral artery (PCA) aneurysms are encountered rarely. Although computed tomographic (CT) scan features of giant intracranial aneurysms have been described. CT scan features of acutely ruptured giant saccular PCA aneurysms have not been reported. A case of an acutely ruptured giant saccular PCA aneurysm with diagnostic CT scan features and autopsy confirmation is presented. Two additional cases of apoplexy with identical clinical courses and CT scan appearances, both attributed to giant saccular PCA aneurysms, are described. Diagnostic CT scan features included evidence of intraparenchymal temporal lobe and intraventricular hemorrhage, the presence of a filling defect in the temporal lobe hematoma that enhanced after intravenous contrast administration, and evidence of proximal PCA entrance into the contrast-enhanced filling defect in the intracerebral hematoma. The incidence of PCA aneurysms and the anatomy of the PCA as it relates to these giant aneurysms, their clinical presentation, and diagnostic features of the CT scan are discussed.