MRI of Kernohan's Notch in a Ruptured Distal Anterior Cerebral Artery Aneurysm : A Case Report

Abstract

A 60-year-old female presented with a massive left subdural hematoma caused by the rupture of a distal anterior cerebral artery aneurysm. On admission, she was comatose with fixed and dilated pupils, showing a decerebrate posture. She underwent an emergency operation. The subdural hematoma was removed and an external decompression was also undertaked. Her level of consiousness gradually improved and a left hemiplegia became evident. A T2-weighted MRI revealed a lesion in the right cerebral peduncle on the extending line of the tentorium. Such hyperintense lesions may represent the myelin desruction around Kernohan's notch.