The use of computed tomography in the prediction of delayed cerebral infarction following acute aneurysm surgery for subarachnoid haemorrhage.

In order to predict the occurrence of cerebral infarction after aneurysmal surgery in patients with subarachnoid haemorrhage, we measured the amount of subarachnoid blood on initial and on postoperative computed tomograms. We used a reliable grading method to estimate the amount of blood on computed tomograms in 24 patients with infarction due to vasospasm and 45 patients without cerebral infarction, all of whom underwent aneurysmal surgery within 48 hours after the ictus. The total amount of subarachnoid blood on admission and on the day after operation was more in the cerebral infarction group than in the non-infarction group. The clearance rate of subarachnoid blood by surgery was lower in patients with cerebral infarction than in patients without infarction and the predominant site of subarachnoid blood corresponded with the site of the infarct. Of 24 patients with cerebral infarction, 22 (92%) belonged to the group whose initial total blood score was more than 10 on admission and whose clearance rate by surgery was less than 50%. Therefore, we propose this range to be an indication for the occurrence of cerebral infarction in postoperative patients due to cerebral vasospasm. The presence of intracerebral haematoma and the amount of ventricular blood and their clearance by surgery were also estimated for the prediction of delayed cerebral infarction after aneurysmal surgery. However, they had no relation to the occurrence of cerebral infarction due to vasospasm.