RESUMO
PURPOSE: Aim of this study was to evaluate the collateral blood flow between more distal branches of the middle cerebral artery (MCA) in the case of peripheral MCA branch occlusion on dynamic 4D angiograms. We sought to individually predict the finally resulting infarction volume with regard to the extent of collateral blood flow. METHODS: Overall, 35 acute ischemic stroke patients with peripheral MCA branch occlusion were included. Volumes of the ischemic infarctions and perfusion deficits were measured on diffusion-weighted images DWI and time-to-peak TTP (> 4 s). Collateral flow on 4D MR angiograms were classified as previously specified. RESULTS: On DWI, the ischemic lesions had a mean volume of 3.4 ± 15.1 mL while the mean volume on TTP (> 4 s) was significantly larger 22.0 ± 18.1 mL (P < 0.001). On dynamic 4D angiograms we observed grade 1 in 8 (22.9%), grade 2 in 4 (11.4%), grade 3 in 10 (28.6%), and grade 4 in 13 (37.1%) patients. In comparison to patients with better collateralization (grade 3-4) patients with less sufficient collateralization (grade 0-2) demonstrated larger infarction volumes on initial (11.1 mL (IQR 2.9-35.5) vs. 2.1 mL (IQR 0.5-4.5), P = 0.03) and follow-up DWI (15.5 mL (IQR 12.6-23.3) vs. 1.9 mL (IQR 0.5-4.5), P = 0.03) with prominent infarction growth (7.4 mL (IQR 2.6-10.1) vs. 0.9 mL (IQR 0.2-2.6), P = 0.08). CONCLUSIONS: In the majority of cases with distal MCA branch occlusion a good collateral blood flow has been observed. Nevertheless, in approximately one quarter of patients an insufficient collateral blood flow has been detected that was associated with substantial infarction growth.