Application value of multi ⁃ slice spiral CT angiography in carotid atherosclerotic plaque in patients with ischemic cerebrovascular disease

Abstract

Objective To investigate the value of multi⁃slice spiral CT angiography (MSCTA) in the evaluation of carotid plaque surface morphology, composition, nature, "napkin ring sign" and carotid remodeling index (RI). Methods A total of 237 patients (390 carotid arteries) with carotid plaque detected by MSCTA from December 2015 to December 2016 were enrolled. They were divided into ischemic event group (136 cases with 212 carotid arteries) and non ischemic event group (101 cases with 178 carotid arteries). Carotid artery stenosis rate was calculated and the degree of stenosis was judged according to North American Symptomatic Carotid Endarterectomy Trial (NASCET). The location of carotid plaque (common carotid artery, bifurcation of common carotid artery and extracranial segment of internal carotid artery), plaque type (fatty plaque, calcified plaque and mixed plaque, ulcerative and non ulcer plaque), carotid RI and "napkin ring sign" were evaluated by post⁃processing techniques such as volume reconstruction (VR), multiplanar reconstruction (MPR), curved planar reconstruction (CPR) and maximum intensity projection (MIP). Results The proportion of moderate and severe carotid artery stenosis and occlusion in ischemic event group was higher than that in non ischemic event group [44.81% (95/212) vs. 21.91% (39/178); χ2= 22.501, P = 0.000). A total of 206 carotid plaques were detected in the ischemic event group and 209 in the non ischemic event group, occurred in the bifurcation of the common carotid artery [45.63% (94/206) vs. 47.37% (99/209); χ2= 0.136, P = 0.934]; in the ischemic event group, mixed plaques which mainly composed of fat [34.95% (72/206) vs. 12.92% (27/209)] and fatty plaques [38.83%(80/206) vs. 23.44% (49/209); χ2= 64.749, P = 0.000), the proportion of ulcerative plaque [8.74% (18/206)
vs. 2.87% (6/209); χ2= 6.554, P = 0.001] and the positive rate of "napkin ring sign" [12.62% (26/206) vs. 2.87% (6/209); χ2= 10.161, P = 0.001] were all higher than those in the non ischemic event group. The carotid RI in the ischemic event group was also higher than that in the non ischemic event group (1.13 ±0.11 vs. 1.04 ± 0.12; t = 2.254, P = 0.028). Conclusions "Napkin ring sign" can be seen in carotid artery fatty plaques, mixed plaques dominated by fat components, ulcerative plaques and MSCTA, which are more likely to cause clinical cerebral ischemia events. As a noninvasive imaging method in vivo, MSCTA can accurately display and analyze the morphological characteristics and properties of plaque, and has important clinical value in the assessment of plaque vulnerability.

DOI:10.3969/j.issn.1672⁃6731.2020.10.008