目的探讨Ⅲb型主动脉夹层的CT征象,并分析其特点。方法收集Ⅲb型主动脉夹层16例,对其CT表现进行回顾性分析。结果16例5年存活率100%,新月型瓣膜12例,假腔位于左前或侧方15例;假腔有血栓9例,完全被血栓填塞3例;CT表现“双腔影”13例,“三腔影”3例;周围有渗漏6例。结论Ⅲb型主动脉夹层如及时诊断治疗5年存活率高,弯曲突向假腔的新月型瓣膜及假腔位于左侧、左前或左后方是Ⅲb型主动脉夹层CT影像表现特点。 Objective To investigate the CT signs of type Ⅲb aortic dissection and to analyze its characteristics. Methods 16 cases of type Ⅲb aortic dissection were collected and their CT findings were retrospectively analyzed. Results There were 16 cases with 5-year survival rate of 100%, 12 cases of crescent-shaped valve, 15 cases of false cavity located in left anterior or lateral side, 9 cases of thrombosis in fake cavity and 3 cases of thrombus stuffing completely. , “Three cavity shadow” in 3 cases; 6 cases of leakage around. Conclusions The Ⅲ b aortic dissection has a high survival rate of 5 years after timely diagnosis and treatment. The crescent-shaped valve and false lumen projecting to the false lumen are located on the left, left anterior or posterior left posterior.