3D-TOF MRA单侧颈内动脉假性闭塞原因分析  

Analysis of pseudo-occlusion of unilateral internal carotid artery in 3D timeof-flight magnetic resonance angiography

作　　者：丁建荣[1] 潘璟琍[1] 樊树峰[1] 张冰茜[1] 米玉成[1] 

机构地区：[1]浙江省台州医院放射科,浙江临海317000

出　　处：《医学影像学杂志》2012年第12期1997-2000,共4页Journal of Medical Imaging

摘　　要：目的探讨引起3D-TOF MRA颈内动脉及其分支假性闭塞的原因及表现。方法实验组:在10例受试者右侧锁骨上1cm颈总动脉搏动处粘贴直径9mm、厚度1.5mm的圆形体小铁片,分别作磁共振平扫、加与不加磁化传递对比(MTC)的横断位3D-TOF MRA,并任选其中两例进行了相位对比法(PC法)MRA检查。病例组:任选10例确诊的单侧大面积脑梗塞病例和1例大动脉炎致右侧颈内动脉闭塞病例,对比分析两组平扫及MRA表现。结果实验组磁共振平扫正常,无明显伪影;贴铁片后在横断T2WI上颈内动脉颅内段出现流空效应而呈现低信号;加MTC的3D-TOF MRA中右侧颈内动脉及其分支不显示,PC法两侧颈内动脉及其分支对称显示;去掉MTC的3D-TOF MRA中两侧颈内动脉及其分支对称显示。病例组3D-TOF MRA中右侧颈内动脉及其分支不显示,在横断T2WI上颈内动脉颅内段出现等、高信号,梗塞病例均出现颅内大面积梗塞病变;大动脉炎病例颅脑磁共振平扫正常,但3D-TOF MRA基地动脉环前后交通支开放,对侧颈内动脉代偿性增粗。结论颈部的铁磁性异物可引起加MTC的3D-TOF MRA颈内动脉假性闭塞现象,造成误诊,但假性闭塞有其特征性,可通过调整参数排除。Objective To analyse pseudo-occlusion of unilateral internal carotid artery in 3D time-of-flight magnetic reso- nance angiography. Methods Experimental group： 10 normal volunteers were enrolled to accept the test. T1/T2/ T2 FLAIR and 3D TOF-MRA with/without magnetization transfer contrast （MTC） were performed with an iron plate pas- ted on the skin of pulsation at the right common carotid artery. Phase contrast （PC） MRA were randomly implemented on two of them. Patient group： 10 cases of massive cerebral infarction and 1 case of takayasu arteritis with unilateral internal carotid artery occlusion were retrospectively analysed. Manifestation of plain scan MR images and MRA were compared between experimental group and patient group. Results Experimental group： In an image obtained by 3D TOF-MRA with MTC pulse, the vascular signal of right internal carotid artery was almost disappeared on all volunteers with pasted iron plate. However, in 3D TOF-MRA without MTC pulse, the right internal carotid artery was clearly visualized. The pres- ence of signal void of right intracranial segment of internal carotid artery on T2 WI caused by vascular flow void effect was a clue to the correct diagnosis. Patient group： In images obtained by 3D TOF-MRA with MTC pulse, the vascular signal of unilateral internal carotid artery was almost disappeared on all the sides with disease, and intracranial segment of inter- nal carotid artery of lesion side on T2WI displayed as equal or high signal. In the case of takayasu arteritis, anterior and posterior communicating arteries were opened, and left common internal carotid artery were enlarged with compensation. Conclusion Compared to true occlusion of intracranial segment of internal carotid artery, pseudo-occlusion caused by sus- ceptibility artifacts induced by metallic material near the subject＇s neck in 3D TOF-MRA with MTC has some certain typi- cal characteristics and can be eliminated by adjusting scan parameters.

关 键 词：磁共振血管成像 假性闭塞 颈内动脉 磁化传递对比 

分 类 号：R445.2[医药卫生—影像医学与核医学] R743[医药卫生—诊断学]