三维增强MR血管造影在主动脉夹层诊断中的价值

The value of 3D contrasted-enhanced MR angiography in diagnosis of aortic dissection

目的评价三维增强MR血管造影(3DCEMRA)及其三维重建在诊断主动脉夹层中的价值及其临床意义。方法136例主动脉夹层患者用屏气超快速三维梯度回波序列行3DCEMRA检查,工作站上三维重建。后处理技术包括容积显示(VR)、多平面重建(MPR)、最大密度投影(MIP)及仿真内镜(VE)。其中,21例行手术治疗,32例因接受腔内隔绝术行DSA造影。结果(1)136例均能显示明确的真假腔及内膜片,Ⅰ型夹层27例,Ⅱ型2例,Ⅲ型107例。(2)105例可见到明确的初始破裂口。与DSA比较,3DCEMRA对初始破裂口的显示率为100%,对总体破裂口的显示率为91.4%。初始破裂口以在VR及MPR像上显示为佳,尤其是VR像,可立体显示破裂口形态、大小及与主动脉分支的关系,对手术或血管腔内隔绝术帮助较大。(3)Ⅰ型夹层中,10例(10/27)右无名动脉受累;Ⅲ型夹层中,10.3%(11/107)的左锁骨下动脉受累。腹主动脉分支受累中,32.1%(43/134)的肾动脉受累,14.9%(20/134)的腹腔动脉干受累;40.3%(54/134)仅累及1支,12.7%(17/134)累及2支或3支。(4)22.8%(31/136)的假腔完全被血栓充填,为主动脉壁内血肿。结论3DCEMRA是无创、快速、准确诊断主动脉夹层最有效的影像学检查方法之一,能指导治疗方案的制定,对手术及腔内隔绝术具有较大的帮助。

Objective To assess the value of three-dimensional contrast-enhanced MR angiography （3D CE-MRA） and its reconstruction in diagnosis of aortic dissection （AD） . Methods One hundred and thirty-six patients with AD underwent 3D CE-MRA with a 3D FLASH sequence after injection of 0.2mmol Gd-DTPA per kg b. w. The source images were subtracted from mask images and transferred to computer workstation subsequently post-processed using volume rendering （VR）, maximum intensity projection （MIP） , multiplaner reformation （MPR） and virtual endoscopy （ VE ）. Results （ 1 ） Double lumen and intimal flap could be shown in all of 136 patients. There were 27 DeBakey type I dissections, 2 type Ⅱ dissections and 107 type Ⅲ dissections. Twenty-one cases were confirmed by surgery, and 32 cases, by DSA with endovascular graft exclusion. （2） Initial entry sites were defined in 105 cases. Compared with DSA, the depiction of 3D CE-MRA was 100% for initial entry sites and 91.4% for multi entry sites. Depiction of the initial entry sites was significantly better with VR and MPR, especially VR images. The shape, size and the relationship between the arterial orifice and the initial entry sites were clearly demonstrated with three-dimension on VR images, which was very helpful for surgery and endovascular graft exclusion. （3） The orifice of anonymous artery involved in type Ⅰ dissections was 10（10/27）, and the orifice of left subclavian artery involved in type Ⅲ dissections, 10.3 percent. In 134 patients with type Ⅰ and type Ⅲ dissections, the kidney arterial orifice was involved in 32.1 percent; the celiac arterial orifice, 14.9 percent; the super mesenteric arterial orifice, 4.5 percent. Single artery involved was about 40.3 percent, and multi arteries, 12. 7 percent. （4） The false lumen with completely thrombi, that was intramural hematoma, was found in 31 patients （22.8%）. Conclusion 3D CE-MRA is a non-invasive, fast and effective method in diagnosis of AD. It provides more reliable information for surgery and endovascular treatment.