Early cerebral blood flow and computerized tomography in predicting ischemia after cerebral aneurysm rupture.

Cerebral blood flow (CBF) was measured during the 1st week of subarachnoid hemorrhage in 46 patients who were in a good clinical grade and had a proven ruptured intracranial aneurysm. The mean initial CBF in patients who developed cerebral ischemia was 42 ml/min-1/100 gm brain-1, which was significantly lower than in patients who did not develop cerebral ischemia (49 ml/min-1/100 gm brain-1). This reduced CBF was not secondary to raised intracranial pressure or angiographic spasm. Patients with a reduced CBF (less than 50 ml/min-1/100 gm brain-1) and diffuse subarachnoid blood on computerized tomography had a very high incidence (78%) of cerebral ischemia, despite a good clinical grade at the time of measurement. Serial CBF measurements are of value in monitoring the evolution of cerebral vasospasm.