Outcome of acute ischemic stroke with absent opacification of the cervical internal carotid artery at CT-angiography after endovascular treatment

Purpose: Occlusion of the distal internal carotid artery can simulate a proximal occlusion of its cervical tract on CT angiography in patients with acute ischemic stroke, that is, pseudo-occlusion. As true and false carotid occlusions can present similarly on non-invasive imaging in patients undergoing endovascular treatment for stroke, our study aimed to evaluate clinical and technical differences of these conditions and the possible consequences of a misdiagnosis. Methods: We retrospectively reviewed consecutive patients who underwent mechanical thrombectomy for acute ischemic stroke at a single center between July 2015 and May 2022 and included patients with absent opacification of the cervical carotid artery on CT-angiography. Digital subtraction angiography (DSA) imaging and procedural data were evaluated to define the actual localization of the occlusion. We compared imaging and clinical data between patients with true and false carotid occlusion, including collateral circulation at CTA, revascularization grade, and clinical outcome at 3 months. Results: A total of 116 patients were included, 63 (54%) of whom had true occlusion of cervical internal carotid artery. Compared to the pseudo-occlusion group, collateral circulation at CTA was moderate to good in 75% of cases (vs 32%; p < 0.0001) and the mean ASPECT score at 24 h was 7 versus 2 (p < 0.0001). Modified Rankin scale 0-2 at 90 days was more frequent in patients with true occlusion than those with pseudo-occlusion (48 vs 11%; p = 0.0002). Conclusion: Pseudo-occlusion of the cervical internal carotid artery in patients with acute ischemic stroke appears to be associated with worst prognosis and poorer collateral circulation in comparison with tandem occlusion.