Thrombus Imaging Features for Anterior Circulation Stroke: Their Impact on CTP Parameters and Natural Evolution of...

Background/Objectives: The relationship between thrombus imaging features and the natural evolution of stroke remains poorly defined. We aimed to investigate the associations between thrombus characteristics on CT and perfusion parameters, as well as subsequent infarct progression, in untreated patients experiencing an anterior circulation acute ischemic stroke (AIS). Methods: This retrospective analysis enrolled 81 untreated patients with AIS who underwent baseline non-contrast CT (NCCT), CT angiography (CTA), CT perfusion (CTP), and a follow-up NCCT. We evaluated the thrombus length, location, and clot burden score (CBS). CTP parameters included the ischemic core, hypoperfused tissue, and penumbra volumes. Infarct growth was the difference between the final infarct volume on a follow-up NCCT and the initial core volume on CTP. Univariate and multivariate regression models were performed. Results: Higher CBS values and shorter thrombi are associated with a reduced ischemic core (coefficients B of -3.9 and 0.88, p < 0.01), diminished hypoperfused tissue (coefficients B of -12.2 and 2.87, p < 0.001), and smaller penumbra volume (coefficients B of -7.9 and 1.99, p < 0.001). More distal occlusions were associated with smaller perfusion deficits. Importantly, a higher CBS and more distal thrombus location were significantly associated with a smaller final infarct volume and infarct growth volume. Conclusions: In untreated AIS patients, a lower thrombus burden (higher CBS, shorter length, distal location) is associated with more favorable baseline perfusion parameters and predicts a slower, less severe natural evolution of AIS. These findings underscore the prognostic value of baseline thrombus characteristics in determining the intrinsic course of a stroke.