Prediction of cerebral infarction due to vasospasm following aneurysmal subarachnoid haemorrhage using acetazolamide-activated 123I-IMP SPECT.

Prediction of cerebral infarction due to vasospasm (VS) following aneurysmal subarachnoid haemorrhage (SAH) was investigated using acetazolamide-activated (A-A) N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) single photon emission computed tomography (SPECT) in 79 SAH patients. A-A SPECT was undertaken twice or more for one each patient by Day 18. Fifty-six (71%) of the 79 patients presented with reduction of cerebral vasodilatory capacity (CVC) on SPECT due to VS by Day 18. Of the 56 patients, 29 showed CVC by Day 8 (Group A), while the other 27 first showed CVC reduction between Day 9 and 18 (Group B). Cerebral infarction on CT was revealed by Day 18 in 15 patients (52%) of Group A and 3 (11%) of Group B. Of the 56 patients, 20 showed reduced CVC in watershed[s] (Type 1), 12 in a sole territory of the intracranial major arterial trunk (Type 2), and 24 in several territories or in a sole territory with distant watershed[s] (Type 3). Cerebral infarction on CT by Day 18 was revealed in one patient (5%) in Type 1, 3 (25%) in Type 2, and 14 (58%) in Type 3. Twelve (71%) of 17 patients belonging to both Group A and Type 3 resulted in cerebral infarction. These results suggest that early and extensive CVC reduction are significant factors responsible for cerebral infarction due to VS following SAH. Cerebral infarction can be reasonably predicted using A-A SPECT in SAH patients.