Relationship Between Collateral Status, Contrast Transit, and Contrast Density in Acute Ischemic Stroke

Abstract

Background and Purpose— Collateral circulation is recognized to influence the life expectancy of the ischemic penumbra in acute ischemic stroke. The best method to quantify collateral status on acute imaging is uncertain. We aimed to determine the relationship between visual collateral status, quantitative collateral assessments, baseline computed tomographic perfusion measures, and tissue outcomes on follow-up imaging. Methods— Sixty-six consecutive patients with acute ischemic stroke clinically eligible for recanalization therapy and with M1 or M2 middle cerebral artery occlusion were evaluated. We compared the visual collateral scoring with measures of contrast peak time delay and contrast peak density. We also compared these measures for their ability to predict perfusion lesion and infarct core volumes, final infarct, and infarct growth. Results— Shorter contrast peak time delay ( P =0.041) and higher contrast peak density ( P =0.002) were associated with good collateral status. Shorter contrast peak time delay correlated with higher contrast peak density ( β =−4.413; P =0.037). In logistic regression analysis after adjustment for age, sex, onset–computed tomographic time, and occlusion site, higher contrast peak density was independently associated with good collateral status ( P =0.009). Multiple regression analysis showed that higher contrast peak density was an independent predictor of smaller perfusion lesion volume ( P =0.029), smaller ischemic core volume ( P =0.044), smaller follow-up infarct volume ( P =0.005), and smaller infarct growth volume ( P =0.010). Conclusions— Visual collateral status, contrast peak density, and contrast peak time delay were inter-related, and good collateral status was strongly associated with contrast peak density. Contrast peak density in collateral vessel may be an important factor in tissue fate in acute ischemic stroke.