轻中度血管狭窄重构模式与斑块易损性的高分辨磁共振研究

High-resolution magnetic resonance imaging for mild-to-moderate vessel stenosis reconstruction mode and plaque vulnerability: report of 32 cases

目的应用高分辨磁共振成像技术评估轻中度狭窄的颈动脉血管重构模式,探讨血管重构模式与颈动脉斑块在缺血性脑卒中事件发生、发展中的关系。方法纳入经超声诊断颈动脉粥样硬化,且斑块≥2 mm发生急性缺血性脑梗死或短暂性脑缺血的患者32例,进行高分辨磁共振斑块成像。根据斑块的信号、表面纤维帽的完整性判定斑块的稳定情况;同时测量斑块最厚层面、远端及近端参考点的总管腔、管壁面积,计算出管壁标准化指数、重构指数(remodeling index,RI)、斑块负荷及斑块大小。RI≥1.05为正性重构(positive remodeling,PR),RI<1.05为非正性重构(non-positive remodeling,nonPR)。比较PR组与Non-PR组测量指标的差异,并对重构模式与斑块易损性进行相关性分析。结果共检出55个颈动脉斑块,PR组与Non-PR组在总管腔、管壁面积、管壁标准化指数上差异无统计学意义(P>0.05),两组斑块负荷及斑块大小差异有统计学意义(P<0.001)。重构模式与斑块易损性的相关性分析差异无统计学意义(χ~2=0.532,P>0.05)。结论轻中度血管狭窄早期以PR为主,重构模式与斑块的易损性无正性相关,斑块自身成分的变化是导致缺血性脑卒中事件发生至关重要因素。

Objective To evaluate artery reconstruction mode for mild-to-moderate stenosis of carotid by high resolution magnetic resonance imaging（ HR-MRI）, and explore the relationship of vascular reconstruction mode with carotid artery plaque in the occurrence and development of ischemic cerebral stroke events. Methods Thirty-two patients with transient ischemic attack or ischemic stroke admitted in our hospital from December 2015 to December 2016 were enrolled in this study. They all had ultrasonic diagnostic hints of carotid artery atherosclerosis,plague size ≥ 2 mm,and acute ischemic cerebral infarction and transient ischemic attack,and were scanned with high resolution magnetic resonance imaging. According to the signal intensity of the plaques and surface integrity of fiber cap,the plaque stability was assessed,and the thickest point of reference for the distal and proximal main chamber,total vessel area,lumen area were simultaneously measured. Normal wall index,remodeling index（ RI）,plaque burden and plague size were calculated. RI≥1. 05 was defined as positive remodeling（ PR）,and RI 〈1. 05 as non-positive remodeling（ non-PR）. Independent sample t-test was used to compare the differences in measured data between PR group and non-PR group. Chi-square test was performed to explore the correlation between remodeling patterns and plaque vulnerability. Results Fifty-five carotid plaques were found by HR-MRI. There were no statistically significant differences in the total vessel area,lumen area and normal wall index between PR and non-PR group（ All P 〈0. 05）. The differences in plague burden and plague size were statistically significant（ P 〈0. 001）. There was no statistically significant correlation between the reconstruction mode and plague vulnerability（ Chi square = 0. 532,P 〈0. 05）. Conclusion PR makes a point in mild-to-moderate early vascular stenosis. Remodeling mode has no positive correlation with plaque vulnerability. And the change of plaque composition is essential factor of ischemic stroke event.