Contrast agent retention sign in angiography predicts acute internal carotid artery embolic occlusion

Abstract

BackgroundIdentification of acute internal carotid artery embolism (ICAE) and internal carotid artery atherosclerotic stenosis (ICAAS) in acute ischemic stroke patients is important for selection of treatment. The presence of contrast agent retention on pre-procedural angiographic images is more common in patients with ICA occlusion caused by embolism compared to patients with ICA atherosclerotic stenosis. This study aimed to evaluate effectiveness of contrast agent retention sign for predicting ICAE. MethodsSixty-five patients with ICA occlusion who underwent emergency endovascular treatment from September 2014 to September 2020 were included in this retrospective analysis. Patients were divided into ICAE (n = 46) and ICAAS (n = 19) groups. Clinical characteristics, imaging data and ICA contrast agent retention signs of patients were collected. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnosis accuracy of contrast agent retention sign were conducted. ResultsThe positive ICA contrast agent retention sign was significantly more common in patients with ICAE (60.87% vs 0.00%, P < 0.001) than that of patients with ICAAS, but significantly lower in male patients (53.57% vs 81.08%, P = 0.017). There were significantly more patients with positive sign had occlusion in C6 segment (64.29% vs 13.51%, P < 0.001) and no outflow tract (85.71% vs 5.41%, P < 0.001) compared with negative sign group. There were significantly fewer patients with postive sign had occlusion in C1 segment (0.00% vs 40.54%, P < 0.001) compared with negative sign group. The sensitivity, specificity, PPV, NPV and diagnosis accuracy of contrast agent retention sign for predicting ICAE occlusion were 60.87%, 100%, 100%, 51.35% and 72.31%, respectively. ConclusionThe ICA contrast agent retention sign has very high specificity and moderate sensitivity for detection of acute ICAE.