Computed Angiography in Assessment of Critical Occlusive Carotid Disease – Ability to Observe Different Types of Pathology: Critical Stenosis, Near-occlusion and Local Occlusion with Distal Collateral Supply Through Atypical Ascending Pharyngeal Artery

Abstract

Introduction: The pathologies that correspond to almost terminal occlusion of internal carotid artery (ICA) can vary a lot. Several types were described - critical stenosis, near-occlusion and local occlusion of the artery. Differential diagnosis between them could be achieved with assessment of upper artery segments. Thus aim of our study was to assess computed angiography (CTA) abilities in analysis of internal carotid artery critical atherosclerotic changes. Methods: During 2016-2018 years 323 patients underwent examination (ultrasound and CTA of brachiocephalic arteries) prior to surgical treatment of ICA occlusive disease. CTA was made on Philips iCT 256 slices (noncontrast, arterial and venous phases) with 50 ml on nonionic contrast media injected at rate of 4-4,5 ml/sec. We distinguished several types of ICA changes: stenosis more than 60% and 70%, critical stenosis, near-occlusion (also with distal collapse), local occlusion. Results: From all patients ICA stenosis up to critical level was observed in 104 patients. Cases with only critical narrowing of ICA at atherosclerotic lesion level and normal distal portion were described as critical stenosis (Fig. 1a, Fig. 2a) - 84 patients (26% of all observed cases). Cases with critical narrowing at atherosclerotic plague level and diffuse decrease of upper segments were detected as near-occlusion (Fig. 1b, Fig. 2b) - in 18 cases (5,6% of cases). In 2 patients we were able to observe local occlusion of ICA in the bulbus with distal circulation through atypical ascending pharyngeal artery (Fig. 1c, Fig. 2c). No cases with congenital hypoplasia were detected. In patients with diffuse decrease of upper ICA segments all elements of the circle of Wills were detected in 70% of cases. During surgery CTA results were confirmed, but atherosclerotic plague extension was higher than observed at CT approximately at 10 mm. Conclusion: We can refer critical stenosis, near-occlusion and local occlusion to critical atherosclerotic ICA changes. The one should consider CTA limitations in differentiation of upper part of atherosclerotic plague. In majority of cases decrease in ICA diameter was associated with severe atherosclerotic involvement and not with congenital condition of the circle of Wills. CTA is necessary for preoperative assessment of carotid occlusive disease, especially in critical ICA changes.Figure 2CTA of critical stenosis (a), near-occlusion (b), local occlusion (c) of ICA.View Large Image Figure ViewerDownload Hi-res image Download (PPT) Disclosure: Nothing to disclose