三维对比增强颈部动脉MRA动脉期及延迟期影像分析

摘要

目的:评价颈部动脉增强MRA动脉期及延迟期的临床应用价值.方法:对85例颈部3D CE-MRA图像显示的动脉形态进行分析,观察每例颈部动脉的6支血管即双侧颈总动脉、双侧颈内动脉和双侧椎动脉.扫描采用3.0T MR系统(Siemens.Trio),使用高压注射器经肘静脉注射对比剂马根维显后动态扫描.结果:统计85例的双侧颈总动脉、颈内动脉及椎动脉共510支动脉,比较分析动脉期与延迟期就颈部动脉的形态,结果显示完全一致375支,占73.5%,不一致135支,占26.5%.增强MRA动脉期上,有95支颈动脉或椎动脉表现为轻度狭窄,占不一致135支的70.4%,而在延迟期表现为正常.表现在左侧颈总动脉起始部18支,右侧颈总动脉起始部5例,左侧椎动脉起始部38支,右侧椎动脉起始部7例,左侧颈内动脉虹吸段15支,右侧颈内动脉虹吸段12支.另有40支动脉在增强MRA动脉期图像表现为中一重度狭窄,在延迟期则表现为轻度狭窄,夸大了狭窄的程度,占不一致135支的29.6%.其中左侧颈总动脉起始部19支,右侧颈总动脉起始部2支,左侧椎动脉起始部16支,右侧椎动脉起始部3支.结论:3D CE-MRA动脉期易导致动脉的起始部及迂曲部位狭窄的假阳性或夸大狭窄程度,因此在进行3D CE-MRA时不应只进行动脉期扫描,还要进行延迟期的扫描.同时还应结合原始图像,这样才能准确评价动脉的狭窄程度.%Objective: To evaluate the value of arterial and delay phase in cervical artery 3D CE-MRA in clinic. Methods:Cervical artery 3D CE-MRA was performed in 85 cases. Bilateral common carotid arteries (CCA) . internal carotid arteries (ICA ) and vertebral arreries (VA) were observed in arterial and delay phase in all cases. CE-MRA was performed on a 3. 0 T Trio Siemens MRI scanner, with dynamic scan of the IV gadolinium bolus. Maximum intensity project (MIP) was adopted to reconstruct 3D imagines in all cases. Results:510 arteries include bilareral CCA. ICA and VA in 85 cases were analyzed. The artery shape was the same between arterial and delay phase in 375 arteries, 73. 5％ (375/510), The artery shape was the different between arterial and delay phase in 135 arteries. 26. 5％ (135/510). 95 arteries (18 left CCAs primary section, 5 right CCAs primary section , 38 left VAs primary section. 7 right VAs primary section, 15 left carotid siphon af ICA. 12 right carotid siphon of (ICA) were showed slight stenosis in arterial phase, but they are normal in delay phase. 40 arteries (19 left CCAs primary section, 2 right CCAs primary section. 16 left VAs primary section. 3 right VAs primary section) were showed middle to severe stenosis. but they are only slight stenosis in delay phase. Conclusion; False positive or exaggerated stenosis in arrery tortuosity segment or initial segment was observed in arterial phase of 3D CEMRA. In clinic, delay phase scan should be done accompany by arterial phase scan. The primary imaging of 3D CE-MRA should be observed combining with MIP so that the stenosis degree of artery could be diagnosed accurately.