胸主动脉假性动脉瘤的MRI诊断

目的 评价MRI对胸主动脉假性动脉瘤的诊断价值，方法，对16例假性动脉瘤患者行心电图门控MRI扫描，结果 本组假性动脉瘤均位于主动脉轮廓之外，瘤体较大（2.8cm*3.2cm*4.0cm-4．3cm*5.6cm*10.0cm)，偏于一侧，境界清楚，形状不规则，其中不多数（13例）瘤体内部可与血流信号相同的小瘤腔（0．1cm*0.6cm*0.8cm-0.3cm*2.0cm*3.0cm)，瘤壁较厚，信号呈不均匀层状，在SE图像上为中等信号或中等度高信号，在GRE电影图像上为较低信号，可见裂隙状破口以及经破口向瘤腔内喷射的血液信号；3例无瘤腔者MRI未显示破口，瘤体信号与有瘤腔者相同。结论 MRI可显示假性动脉瘤的特异性征象，是假性动脉瘤影像学论断方法之一。

The Diagnosis of Thoracic Aortic Pseudoaneurysm by MRI

Purpose To evaluate the diagnostic value of MRI in thoracic aortic pseudoaneurysm. Methods Sixteen patients, which course was five months to four years, were scanned with ECG-gated SE and GRE pulse sequences. The diagnosis of thoracic aortic pseudoaneurysm was corroborated by X-ray aortic angiogram and/or operation. Results The pseudoaneurysm asymmmetric located at outside of aortic contour in all patients, and they were big(2.8cm×3.2cm×4.0cm~4.3cm×5.6cm×10.0cm),clear boundary, and irregular shape. There was small cavity (0.1cm×0.6cm×0.8cm~0.3cm×2.0cm×3.0cm)in the pseudoaneurysm in majority(13 cases)with the same signal intensity of the blood flow, and the thicker aneurysm wall as multi-ply medium or moderate high signal intensity on the SE images, and lower signal intensity on GRE images. If the pseudoaneurysm with the cavity, the slit and the blood flow through the slit ejecting into the cavity of pseudoaneurysm could be seen. There were 3 patients without the cavity in pseudoaneurysm in this group, the signal of them was same with that having cavity, and the slit of pseudoaneurysm could not be seen also. Conclusion MRI can depict the specific signs of pseudoaneurysm, and it is one of imaging modalities of confirmed pseudoaneurysm diagnosis.