Value of Quantitative Collateral Scoring on CT Angiography in Patients with Acute Ischemic Stroke

Case examples of 4 patients with different visually scored collateral grades and corresponding quantitative collateral scores. Each panel shows a maximum-intensity-projection of the CTA image (left) and the segmented vasculature for qCS calculation (right). The automated segmentation on the ipsilateral side is shown in blue and the segmentation on the contralateral side is shown in red. A, Absent collaterals (visual collateral score = 0). CTA of an 83-year-old man with a left-sided M2 occlusion acquired in the early arterial phase. Follow-up infarct volume was 205 mL, and the mRS score was 6. B, Poor collaterals (vCS = 1). CTA of a 79-year-old man with a right-sided M1 occlusion acquired in the equilibrium phase. FIV was 245 mL, and the mRS score was 6. C, Moderate collaterals (vCS = 2). CTA of a 45-year-old woman with a left-sided M1 occlusion acquired in the peak arterial phase. FIV was 24 mL, and the mRS score was 2. D, Good collaterals (vCS = 3). CTA of a 76-year-old woman with a left-sided ICA-T occlusion acquired in the late venous phase. FIV was 48 mL, and the mRS score was 3.

Distribution of quantitative collateral scores per visual collateral score, ranging from absent collaterals (0% filling of the occluded territory) to good collaterals (100% filling of the occluded territory). The quantitative collateral score was significantly different among all visual collateral score groups, except for absent collaterals (grade 0) versus poor collaterals (grade 1).

Receiver operating characteristic curve analysis of visual and quantitative collateral scores for discriminating favorable outcome (mRS 0–2) with areas under the curve of, respectively, 0.65 and 0.68 (A) and large infarct (FIV of >90 mL) with areas under the curve of, respectively, 0.69 and 0.71 (B).