多层螺旋CT三维重建技术诊断急性主动脉夹层的价值

摘要

目的 探讨16层螺旋CT常规及后处理技术诊断急性主动脉夹层(ADD)的价值.方法 对73例急性主动脉夹层常规平扫和增强检查,扫描范围从肺尖到耻骨联合上缘水平,120 kV,160 mAs,扫描视野35～45 cm.原始采集层厚为0.75 mm,重建层厚1.0 mm,间隔1.0 mm.在工作站进行多平面重建(MPR)、曲面重建(CPR)、最大密度投影(MIP)和容积再现技术(VR)重建.结果 73例中包括Stanford A型20例,B型53例.多层螺旋CT诊断AAD的敏感度、特异度均为100%.AAD假腔与真腔交界面呈"鸟嘴"样改变52例,蜘蛛网状改变21例.MPR与CPR对夹层初始破口、内膜瓣和真假腔的显示率分别为94.5%、100%、100%.VR与MIP对初始破口显示率较低,分别为15.1%、13.7%.MIP对内膜瓣和真假腔显示率为71.2%.结论 MPR技术在提高破口显示率和分型准确度方面明显优于VR和MIP.AAD的三维重建技术应选择MPR和VR,不必要做CPR和MIP重建.%Objective To study the value of 16-slicc CT three-dimensional reconstruction in the diagnosis of acute aortic dissection (AAD). Methods A total of 73 patients with acute aortic dissection underwent routine unenhanced and enhanced CT scanning. Scanning range was from the apex of lung to the level of the upper edge of pubic symphysis, using 120 kV, 160 mAs and FOV of 35 - 4 5 cm. The original thickness for the acquisition was 0. 75 mm, reconstructed slice thickness was 1. 0 mm, spacing was 1. 0 mm. Multi-planar reconstruction (MPR) , curved planar reconstruction (CPR) , maximum intensity projection (MIP) and volume rendering (VR) were conducted at the workstation. Results 73 patients included Stanford A type in 20 cases, B type in 53 cases. The sensitivity and specificity of CT in the diagnosis of acute aortic dissection were both 100%. True and false lumen interface manifestation included "back"-likc change in 52 cases and spider web-like change in 21 cases. The displaying rates of MPR and CPR for the initial break, intimal flap and true and false lumen were, respectively, 94. 5%, 100%, 100%. VR and MIP had lower rate for the initial break display, the sensitivity and specificity were respectively, 15. 1 % and 13. 7%. The displaying rates of the intimal flap and the false lumen with MIP were relatively lower, the sensitivity and specificity were both of 71.2%. Conclusion CT MPR technology in improving the rate of break display and the typing accuracy of AAD is superior to VR and MIP. CT three-dimensional reconstructions for diagnosing AAD should select MPR and VR, while CPR and MIP reconstructions arc not necessary.