Thrombus Permeability on Dynamic CTA Predicts Good Outcome after Reperfusion Therapy

BACKGROUND AND PURPOSE: Thrombus permeability assessed on conventional CTA is associated with neurologic outcome in patients with acute ischemic stroke. We aimed to investigate whether dynamic CTA can improve the accuracy of thrombus permeability assessment and its predictive value for outcome. MATERIALS AND METHODS: We reviewed consecutive patients with acute ischemic stroke who had occlusion of the M1 segment of the middle artery cerebral artery and underwent pretreatment perfusion CT. Thrombus permeability, determined by thrombus attenuation increase (TAI), was assessed on 26-phase dynamic CTA derived from perfusion CT. TAI(max) was defined as the maximum TAI among phases; TAI(peak), as TAI of peak arterial phase; TAI(con), as TAI on phase 13. Good outcome was defined as a 3-month mRS score of <= 2. RESULTS: One hundred four patients were enrolled in the final analysis. The median TAI(max), TAI(peak), and TAI(con) were 30.1 HU (interquartile range, 13.0-50.2 HU), 9.5 HU (interquartile range, -1.6-28.7 HU), and 6.6 HU (interquartile range, -5.1-24.4 HU), respectively. Multivariable regression analyses showed that TAI(max) (OR = 1.027; 95% CI, 1.007-1.048; P = .008), TAI(peak) (OR = 1.029; 95% CI, 1.005-1.054; P = .020), and TAI(con) (OR = 1.026; 95% CI, 1.002-1.051; P = .037) were independently associated with good outcome. The areas under the ROC curve of TAI(max), TAI(peak), and TAI(con) in predicting good outcome were 0.734, 0.701, and 0.658, respectively. CONCLUSIONS: Thrombus permeability assessed on dynamic CTA could be a better predictor of outcome after reperfusion therapy than that assessed on conventional single-phase CTA.