Objectives: Internal carotid artery sacrifice (ICAS) may be required in treatment of cerebral aneurysms and tumours and is a high risk procedure. The interventional radiology balloon temporary occlusion test (IRBTO) paired with the two day Tc99m-bicisate brain perfusion study (BPS) can be a useful way to predict the outcome before occluding the artery in question. The purpose of this study is to examine the value of BPS exams as a predictor of stroke risk prior to ICAS. Patients and methods: 14 cases eligible for ICAS were retrospectively reviewed. IRBTO was positive if the patient developed neurological deficit during temporary IRBTO. The BPS exam was positive if the patient showed an area of focal hypo-perfusion on the occlusion phase, but not on the baseline study done 24 hours apart. The exam was negative if there was no perfusion abnormality on either phase. The results of the BPS were compared to occurrences of post-occlusion infarct. Results: ICAS was indicated in 14 cases [mean age 59.2± 25.2, M: F=2:12, aneurysm: tumour = 10:4]. One case with positive IRBTO: therefore did not proceed to BPS or ICAS. The remaining 13/14 (93%) cases had IRBTO, BPS, and subsequent ICAS. Of the remaining patients, 1/13 (8%) had a positive IRBTO and 2/13 (15%) had a positive BPS. Following ICAS (n=13), 4 cases developed infarct. Of those 4, 3 cases were negative on both exams (IRBTO and BPS). One case was positive on BPS and did not develop infarct. One case that was positive on both exams developed infarct after having ICAS at an outside facility. Conclusions: Combined IRBTO and BPS is an effective way in predicting focal neurological deficit prior to ICAS. Considering the risk of ICAS, the best patient outcomes are obtainable when both IRBTO and BPS are performed and negative.