Morphologic Evaluation of Ductus Diverticulum Using Multi -Detector Computed Tomography: Comparison with Traumatic Pseudoaneurysm of the Aortic Isthmus

Objectives: to evaluate morphologic variations at the aortic isthmus with particular attention to ductus diverticulum,a mimicker of traumatic pseudoaneurysm,and to describe differences using computed tomography (ct) images. patients and methods: from december 2013 to december 2014,patients who underwent a chest ct examination after blunt trauma at our emergency department were included. aortic isthmus morphologies were evaluated using multiplanar reconstruction (mpr) and maximum intensity projection (mip) images as follows. type i -concave contour,type ii -convexity without a discrete bulge,or type iii -a discrete focal bulge (defined as ductus diverticulum). results: after excluding 11 cases of traumatic pseudoaneurysm of the aortic isthmus,a total of 432 trauma patients (mean age = 47.1 ± 19.1 years,number of males = 318) were evaluated for aortic isthmus morphology,and classified as follows; type i (n = 240,55.6%),type ii (n = 157,36.3%),and type iii (n = 35,8.1%). as compared with traumatic pseudoaneurysm (n = 11),ductus diverticulum had a smaller vertical diameter (5.5 ± 1.3 mm vs. 11.2 ± 2.7 mm,p < 0.001),a broader base (14.9 ± 4.1 mm vs. 8.8 ± 4.5 mm,p < 0.001),a smoother margin (97.1% vs. 27.3%,p < 0.001),and formed obtuse angle with the aortic wall. furthermore,ductus diverticulum was not associated with the presence of a dissection flap or hemomediastinum. conclusion: ductus diverticulum,a mimicker of traumatic pseudoaneurysm of the aortic isthmus,is a frequently observed anatomic variant during ct examinations. familiarity with its ct imaging findings could avoid it being confused with traumatic pseudoaneurysm in blunt trauma patients. © 2016,tehran university of medical sciences and iranian society of radiology.