The Effect of EC-IC Bypass in Cases of Ischemic Cerebral Lesions

In order to check the effect of an EC-IC bypass in patients with ischemic cerebral lesions, we measured the change in regional cerebral blood flow (% r CBF) in 15 patients who under-went EC-IC bypass surgery based on the criteria of the International Cooperative Study. Using N-isoprophyl-p-[123I] iodoamphetamine (123I-IMP) SPECT, the percent of r CBF was calculated as the ratio of ROI A to ROI B on early images of the rest state and STA-compressed state, postoperative-ly. ROI A was positioned in the low perfusion area (anastomosed site) on SPECT and ROI B was in the opposite side (normal cortex).The following results were obtained: 1) Eleven of the 19 patients (58%) showed a significant in-crease of r CBF. 2) These eleven patients had an EC-IC bypass about 40 days after the ischemic attack. 3) The bypass was more effective on patients with RIND than those with TIA or minor stroke. 4) The operation on patients with watershed infarction was more effective than those with other types of infarction. 5) Bypass operation on patients who did not show a redistribution phenomenon in the low perfusion area on delayed images was not effective.Based upon these results, we consider that the decision to undertake EC-IC bypass surgery in cases of ischemic cerebral lesions should be based at least on measurement of CBF by SPECT.