Visualization of Thrombus Enhancement on Thin-Slab Maximum Intensity Projection of CT Angiography: An Imaging Sign for Predicting Stroke Source and Thrombus Compositions

Background Thrombus enhancement (TE) in large vessel occlusion in patients with acute ischemic stroke can be visualized with thin-slab maximum intensity projection (TS-MIP) image reconstruction of CT angiograms. Purpose To evaluate whether TE on TS-MIP reconstructed CT angiograms can be used to predict thrombus composition and stroke source. Materials and Methods This retrospective study included consecutive patients with acute ischemic stroke who underwent thrombectomy in the anterior circulation between August 2016 and July 2019. Stroke types were classified according to the Trial of ORG 10172 in Acute Stroke Treatment. TE on TS-MIP reconstructed CT angiograms was evaluated by two readers. Various clinical and interventional parameters and histopathologic thrombi examination results were compared between the TE-positive and TE-negative groups. The associations between TE and thrombus compositions and stroke sources were analyzed by using multivariable linear and logistic regression models. Results A total of 148 patients (mean age, 71 years ± 11 [standard deviation]; 94 men) were included. TE was confirmed in 80% (119 of 148) of the patients. TE-positive thrombi contained a higher fibrin and platelet proportion (mean, 46% ± 16 vs 34% ± 13; P = .02) and fewer erythrocytes (mean, 33% ± 14 vs 48% ± 20, P = .002) than the TE-negative thrombi. The proportion of cardioembolic and cryptogenic strokes in the TE-positive and TE-negative groups was 92% (110 of 119) and 24% (seven of 29), respectively (P < .001). In adjusted analysis, the presence of TE (odds ratio, 155; 95% CI: 17, 1438; P < .001) was associated with a combination of cardioembolic and cryptogenic strokes. A multiple logistic regression model showed that TE (odds ratio, 23; 95% CI: 1.8, 288; P = .02) was significantly associated with cardioembolic stroke. Conclusion Thrombus enhancement on thin-slab maximum intensity projection of CT angiography can be used to predict cardioembolic and cryptogenic strokes and identify thrombi with a higher fibrin-to-platelet fraction and a lower erythrocyte proportion. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Kansagra and Goyal in this issue.