IS Case 608: Aortic transection
Imaging Sciences URMC 2011
Publication Date: 2011-12-12
History
The patient is a 19-year-old male, belted driver of a high speed motor vehicle accident, who exhibits altered mental status. This patient was grunting, spitting blood, and thrashing on the gurney.
Findings
Imaging findings demonstrated a widened mediastinum on chest radiograph, mediastinal hematoma with extravasation of contrast at the level of the aortic transection, and arch aortograms demonstrate extravasation of contrast at the level of the ligamentum arteriosum, in the descending thoracic aorta.
Diagnosis
Aortic transection
DDx
Differential diagnoses include a ductus diverticulum or penetrating atherosclerotic ulcer. A ductus diverticulum is characterized by a smooth focal bulge along the anteromedial spect of the aortic isthmus, as a remnant of the ductus arteriosus. A key finding in a ductus diverticulum is that of uninterrupted smooth margins.
Discussion
Aortic transection results from shear stress at points of maximal fixation of the aorta, with a typically transversely oriented laceration. One or more layers of the aorta may be torn. It may occur in patients who experienced blunt or deceleration aortic trauma (motor vehicle accidents or fall from great heights). The aorta may be transected at the isthmus (just beyond the origins of the great vessels), which is most common. Other less common locations include the aortic root and aortic hiatus.
Radiographic findings include mediastinal widening, indistinct aortic outline, right paratracheal soft tissue density, NG tube deviation to the right, rightward tracheal displacement, inferior displacement of the left mainstem bronchus, apical pleural cap, or a first/second rib fracture.
CT findings (which are more specific with the addition of contrast) include obliteration of the aortic-fat interface with high density (consistent with hemorrhage), mediastinal hematoma with rightward displacement of the trachea and esophagus, hemopericardium, intramural aortic hematoma. With intravenous contrast, one may see abrupt change in aortic contour, an intimal flap, pseudoaneurysm, pseudocoarctation due to compression of the lumen by the pseudoaneurysm, and filling defects.
References
- Abbara S, Walker TG. Diagnostic Imaging: Cardiovascular. 1st Edition: AMIRSYS, July 2008
- Samett EJ. Aorta trauma imaging. Updated Apr 12, 2011. http://emedicine.medscape.com/article/416939-overview
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