特殊类型主动脉夹层的电子束CT表现及诊断

目的探讨表现特殊的主动脉夹层的电子束CT(EBCT)影像特征及诊断.材料和方法20例表现特殊的主动脉夹层,其中不典型夹层13例,三腔以上夹层动脉瘤3例,合并升主动脉壁内血肿的Stanford B型夹层2例,动脉瘤样夹层1例,外伤性主动脉夹层1例.结果主动脉不典型夹层为主动脉壁新月形或环形的低密度血肿包绕,常可见穿透性溃疡或钙化内移等征象;三腔以上夹层动脉瘤有2～3个内膜片,3～4个腔,瘤体管径较大;合并升主动脉壁内血肿的B型夹层见升主动脉管壁低密度新月形或环形增厚,降主动脉则见内膜片及真假两腔形成;动脉瘤样主动脉夹层见降主动脉局限性瘤样扩张,破口大,内膜片不易发现.1例外伤性夹层于主动脉弓峡部及降部起始见破裂内膜片.结论特殊类型的主动脉夹层表现各具特征,EBCT可清晰显示,是极适用于胸部急症的快速、无创的检查方法.

Findings and Diagnosis of Special Aortic Dissection by Electron Beam Computed Tomography

Purpose: To investigate the imaging findings and diagnosis of special aorta dissection. Materials and Methods: 20 patients were performed with continuous volume scanning(CVS) of EBCT. There were 13 cases with atypical aortic dissection, 3 cases with three or more channeled dissection,2 cases with type B dissection combined with ascending aortic intramural hematoma, 1 case with aneurysm like aortic dissection and 1 case with traumatic dissection in aorta. Results: Atypical aortic dissection showed crescent or annular low density with thickening wall, usually with penetrating ulcer or calcification ingression. Three or more channeled dissection revealed two or three intimal flaps and three or four lumens.Type B dissection combined with intramural hematoma in ascending aorta and intimal flap and true and false lumens in thoracic and abdominal aorta. The aneurysm like dissection of aorta showed local enlargement of aorta and large entry tear and short intimal flap. Traumatic aortic dissection showed intimal flap in aortic isthmus and proximal descending aorta. Conclusion: EBCT is a fast and noninvasive diagnostic tool for thoracic emergency,and could clearly show respective imaging features of special aortic dissection.