胸主动脉MR仿真内镜检查的临床应用及其缺陷

目的：研究MR仿真内镜（MRVE）对胸主动脉解剖及病变的临床应用价值。探讨其成像方法及存在缺陷。方法：对20例健康检查者及33例临床考虑胸主动脉病变的患者行MR三维动态增强扫描血管成像（3D-DCE-MRA）检查，将其原始数据进行仿真内镜重建处理，观察其对血管内表面解剖及病变的显示能力。结果：MRVE直观地显示胸主动脉解剖及病变情况，21例夹层动脉瘤，MRVE清楚地显示夹层动脉瘤入口，内膜移位及瘤腔情况；对主动脉瘤及大动脉炎可显示其扩张或缩窗的内腔结构；对法乐氏四联征，清楚地显示主动脉骑跨及骑跨程度；半环状伪影为MRVE主要存在的伪影。结论：MRVE能直观地显示胸主动脉内壁的解剖及病变情况，可作为临床怀疑胸主动脉病变患者的常规检查手段。

The value and limitation of MRVE of thoracic aorta

Objective:To assess the value and limitation of thoracic aortic MR virtual endoscopy(MRVE)and discuss its imaging technique. Methods:20 volunteers and 33 patients of thoracic aortic lesions were performed 3 dimensional dynamic contrast enhanced MR angiography (3D DCE MRA),from which MRVE were reconstructed to demonstrate the inner wall and lesions of thoracic aorta,and its visualization was also evaluated.Results:MRVE intuitively showed the anatomy and lesions of thoracic aorta.In 21 cases of aortic dissection, MRVE documented clearly the inlet,intimal flap displacement and lumina of aortic dissection,while the dilatation or narrowing of lumen of aortic aneurysm and aortitis was also shown by MRVE.For Fallot's tetralogy,the overriding aorta and the degree of the overriding were distinctly documented by MRVE.And half circle artifact was the main artifact of MRVE in this series. Conclusion: MRVE can intuitively show the inner wall and lesions of thoracic aorta,and be regarded as a routine examination for the patient with suspected thoracic aortic diseases.