Cine MR Imaging of Aortic Dissection ; Comparison with Spin-echo MR Imaging.

为了评价电影磁共振成像(Cine MR)在主动脉夹层诊断中的作用，我们回顾了53例患者的自旋回波磁共振成像(SPIN-ECHO MR)和电影MR，其中53例经CT证实，30例经主动脉造影证实，5例经手术证实。根据CT表现分为三组：双管型30例，血栓型18例，穿透性动脉粥样硬化性溃疡5例。A型13例，A+B型3例，B型37例。在双管型中，30例患者中有29例可以用自旋回波磁共振分辨内膜瓣和真假腔，而在电影磁共振上可以全部辨别。磁共振自旋回波显示真腔和假腔内不同的信号，双腔血流呈高信号，电影显示慢血流和部分血栓呈低信号，在Fal…上可见小的信号空洞在自旋回波MR上26例患者和电影MR上24例患者有更多的管腔。在另外2例患者中，电影MR上没有观察到通过大入口的信号空洞。通过将电影MR的最佳轴向平面固定到通信口作为参考自旋回波MR上看到的信号空洞的参考，所有3名患者都可以通过通信口来回运动。在6名患者中有4名患者被发现Re-Entry，试图设置电影MR的最佳平面。在18名血栓类型的患者中，因主动脉壁增厚(n=7)或呈亮(n=4)、暗(n=3)等不同信号，自旋回波MR不能单独评价假腔内血流的存在与否，而在电影MR上，血栓形成的假腔呈低信号(n=16)，提示假腔内无血流，呈高信号(n=2)，似双管型。8例溃疡样突起(ULP)和5例穿透性动脉硬化性溃疡(n=5)在自旋回波MR上表现为信号空洞，在电影MR上表现为高信号，其特征与主动脉造影相似。自旋回波信号强度本身并不是区分血栓和血流相关强化的准确指标。由于电影MR图像对血流运动敏感，它们可以使血流产生的信号更有信心地与腔内异常区分开来，从而补充自旋回波图像的发现。总之，电影MR的显示有助于更容易地识别假腔内血流的存在或不存在，以及在心动周期中通过内膜撕裂信号空洞，模拟实时心脏成像，因此电影MR为评价主动脉夹层提供了额外的生理信息。较少

Purpose of this study is to evaluate the role of cine magnetic resonance imaging (cine MR) in the diagnosis of aortic dissection, we reviewed both spin-echo MR imaging (spin-echo MR) and cine MR of 53 patients that had been documented by CT in 53 patients, aortography in 30, and surgery in five. They were divided into three groups ; double-barreled type (n=30), thrombosed type (n=18), and penetrating atherosclerotic ulcers (n=5), according to the CT features. Thirteen patients had type A,three type A+B and 37 type B dissections. In the double-barreled type, identification of the intimal flap, and true and false lumen differntiation were possible with spin-echo MR in 29 of 30 patients, and on cine MR in all 30. Variable intensities in the true and false lumens were shown on spin-echo MR,whereas flowing blood of both lumens was always visualized as a hyperintensity, and slow flow and partial thrombus as a hypointensity on cine MR.The small entry was identified as a signal void in the fal … More se lumen in 26 patients on spin-echo MR,and in 24 on cine MR.In other two patients, signal void via the large entry was not observed on cine MR.To-and-fro movement of flow via the communicating orifice could be identified in all 3 patients on cine MR,by stting the optimal axial plane of cine MR to the communicating orifice as a reference of a signal void seen on spin-echo MR.Re-entry was identified in 4 out of 6 patients with attempt to set the optimal plane of cine MR.In 18 patients with thrombosed type, the presence or absence of flow in the false lumen could not be evaluated by spin-echo MR alone, because of thickened aortic wall (n=7) or showing the various intensities such as bright (n=4), and dark (n=3), whereas on cine MR,the thrombosed false lumen was visualized as a hypointensity (n=16), suggesting no flow in the false lumen, and as a hyperintensity (n=2) mimicking double-barreled type. Outpouching projecting from the true into false lumens of ulcerlike projection (ULP) (n=8) and penetrating atherosclerotic ulcer (n=5) was observed as a signal void on spin-echo MR,and as a hyperintensity on cine MR,which features were similar to that of aortography. Spin-echo signal intensities alone were not accurate indicator in differentiating thrombus from flow-related enhancement. Because cine MR images are sensitive to the movement of flowing blood, they may allow signal produced by flow to be differentiated with more clinical confidence from that of intraluminal abnormality and thus complement findings from spin-echo images. In conclusion, cinematic display of cine MR facilitates more easy recognition of presence or absence of flow in the false lumen, and signal void via the intimal tear during cardiac cycle, simulating real-time cardiac imaging, therfore cine MR provides additional and physiologic information in the evaluaito of aortic dissection. Less