Yu I, Bang OY, Chung JW, et al. - In patients with large vessel occlusion and small core, researchers explored the connection between serial changes in collateral status and infarct volume defined on diffusion-weighted imaging (DWI). The sample consisted of consecutive patients who were candidates for endovascular treatment (Alberta Stroke Program Early CT Score [ASPECTS] of ≥ 6 points) and who had both pretreatment multiphasic computed tomography angiography (mCTA) and multimodal MRI. Using both mCTA and MRI–based collateral maps, the baseline early ischemic changes and collateral status were determined. Of 65 individuals (median age, 76 years; median ASPECTS, 8 points [range, 6–10]), 10 (15.4%), 8 (12.3%), and 47 (72.3%) showed poor, intermediate, and good collaterals on mCTA, respectively. ASPECTS, time to DWI, and mismatch volume, the mCTA collateral grade was the only factor independently linked to the DWI lesion volume after adjusting for the initial stroke severity. An excellent relationship between the mCTA- and MRI-based collateral grades was noted (matching grade seen in 92.3%), indicating a collateral status persistence during the hyperacute stroke phase. The collateral adequacy assessed by the mCTA is the sole predictor of eventual DWI lesion volume prior to endovascular treatment. Further evaluation is required for the added value of collateral assessment in early ischemic changes and large vessel occlusion for decision-making on more aggressive revascularizations.