Longer Length of Delayed-Contrast Filling of Clot on 4-Dimensional Computed Tomographic Angiography Predicts Cardiogenic Embolism.

Background and Purpose- We hypothesized the length of delayed-contrast filling sign (DCFS) of intraarterial clot, indicating contrast medium penetration into the thrombus, was associated with stroke etiology. Methods- We retrospectively included patients with large vessel occlusion in anterior circulation who underwent computed tomographic perfusion within 24 hours poststroke onset. We defined DCFS as contrast medium diffusion through the thrombi after the arterial peak phase on 4-dimensional computed tomographic angiography derived from computed tomographic perfusion. We measured the length of DCFS and investigated its value for predicting the stroke etiology. Results- Three hundred twenty-one patients were analyzed, and their stroke etiologies included cardiogenic embolism (CE, n=167), large artery atherosclerosis (n=64), other etiology group (n=4), and undetermined etiology (n=86). CE patients had longer length of DCFS than non-CE patients (2.3 versus 0.5 mm; P<0.001). The optimal cutoff value of DCFS length for predicting CE was 1.5 mm. The sensitivity, specificity, positive predictive value, and negative predictive value of a length of DCFS >1.5 mm for predicting CE were 83.2%, 70.8%, 75.5%, and 79.6%. Conclusions- Longer length of DCFS was associated with CE in patients with large vessel occlusion in anterior circulation, which may provide stroke etiology information.