Chapter30 Aorta

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Chapter 30: Thoracic Aorta

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Figure 30.48.  Physiologic Ductus Bump. Axial and sagittal CT images ( A , B ) in a trauma patient demonstrate a focal outpouching in the aortic contour ( arrows ) at the ligamentum arteriosum (arrowhead ). Fortunately, this patient had a prior study for comparison; sagittal image from that study ( C ) demonstrates similar morphology representing the ductus bump. It is important to distinguish this finding from aortic injury in the setting of high-velocity injury. Note the absence of mediastinal hematoma or other evidence of blunt trauma in A and B .

normal aortic wall, but anastomotic margins of aortic repair are indicated by an abrupt caliber change in the aorta and foci of high attenuation surgical material. Graft repair of the aortic arch and descending thoracic aorta will have a similar imaging appearance, although aortic arch repair sometimes requires debranching of the aortic arch with reanastomosis or bypass grafting of great vessels. Grafts may also be placed in the native aorta without resec- tion, termed the inclusion technique, resulting in a soft tissue density surrounding the graft representing fluid and throm-

bosis within the native aorta. Atherosclerotic calcification of the native diseased aorta will remain and suggests this type of repair. “Elephant trunk” technique, in which the distal aspect of the graft is left floating in the native aorta, can mimic a dissection (Fig. 30.50). Complications In the immediate postoperative period, perigraft air can be normal and should eventually resolve by 6 weeks postsurgery. Perigraft fluid and soft tissue can also be normal, representing organizing hematoma/fibrosis or edema, and last for months to years following repair. Concern for graft infection should be raised when there is new or increasing perigraft air and fluid collection and contrast enhancement (Fig. 30.51). Rarely,

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Figure 30.49.  Composite Valve-Graft Repair. Coronal oblique CT shows repair of the aortic and ascending aorta with a mechanical aortic valve ( black arrow ) attached to a tubular synthetic graft ( solid white arrow ). Note high attenuation surgical material at the distal anastomosis ( dashed white arrow ) and normal widening of the coro- nary ostia at the site of coronary reimplantation (*).

Figure 30.50.  Elephant Trunk Repair. Sagittal oblique CT. Linear filling defect ( arrow ) in the proximal descending thoracic aorta corre- sponds to the distal aspect of an aortic graft which is left floating in the aorta. This should not be mistaken for a dissection flap.