Origin of sylvian hematoma in patients with subarachnoid hemorrhage: findings of extravasation on multiphase contrast-enhanced computed tomography.

Abstract

Sylvian hematoma in subarachnoid hemorrhage (SAH) is associated with a poor prognosis. Although active bleeding can be detected by multiphase dynamic enhanced computed tomography (CT), bleeding from vessels in the Sylvian fissure has also been found in Sylvian hematoma. We investigated possible origins of Sylvian hematoma based on novel imaging findings of multiphase enhanced CT. We investigated a series of SAH patients with or without Sylvian hematoma. The existence of active bleeding in a Sylvian hematoma was evaluated using multiphase dynamic enhancement CT perfusion scans. The location of the aneurysm as well as regional cerebral blood volume and flow were also recorded. Among 71 SAH patients, 8 were found to have a Sylvian hematoma (11.3%), 3 of which showed multiple extravasations from small vessels apart from the ruptured aneurysms. No extravasations were found in the remaining patients in other cerebral artery territories, even those associated with Sylvian hematoma. No severe perfusion disturbance was observed in patients with extravasation in a Sylvian hematoma. Sylvian hematomas may be caused secondarily by multiple bleeds from small vessels together with aneurysm rupture.