Perimesencephalic Hemorrhage from A Superior Cerebellar Artery Dissection

A 44-year-old women presented with a thunderclap-type headache and brie fl y lost consciousness. She became agitated and required brief intubation. Computed tomography scan of the brain (Figure A,B) showed a large clot in the right perimesencephalic cistern extending into the prepontine, quadrigeminal, and suprasellar cisterns, but not into the lateral Sylvian fi ssures. There was a small clot in the upper part of the third ventricle and early hydrocephalus. Ventriculostomy was placed and cerebro-spinal fl uid came out under high pressure. The 3D cerebral angiogram on day 2 (Figure C) showed some indistinct caliber changes in the superior cerebellar artery. Magnetic resonance imaging of the brain vessel imaging was normal, but the second cerebral angiogram, on day 7, revealed a dissecting aneurysm (Figure D) and was treated with a coil placed in the superior cerebellar artery at its origin. The ventriculostomy could be weaned. The patient made an excellent recovery (she provided written informed consent for publication of deidenti fi ed personal data).