"Lumps" and "bumps" that mimic acute aortic and brachiocephalic vessel injury.

Laceration of the thoracic aorta or brachiocephalic vessels due to blunt trauma is relatively common. In such cases, prompt and accurate diagnosis followed by timely surgery is essential. These injuries typically occur at the aortic isthmus and can usually be readily identified at aortography, which remains the standard of reference for diagnosis. However, numerous anatomic variants that manifest as "lumps" or "bumps" on aortograms can mimic true vascular injury, thereby leading to false-positive or false-negative diagnosis. These variants include aortic spindle, classic or atypical ductal diverticula, and infundibula of the brachiocephalic arteries and adjacent branches or of the right third intercostal artery. Ductus diverticula typically occur at the isthmus and have smooth, uninterrupted margins with gently sloping shoulders. Infundibula are also smoothly marginated but can occur in a variety of locations and generally taper into one or more vessels at their apex. Knowledge of the imaging appearances of these anatomic variants is necessary for correct interpretation of aortograms of the aorta and brachiocephalic vessels in blunt trauma patients.