LUMPS AND BUMPS THAT MIMIC ACUTE AORTIC AND BRACHIOCEPHALIC VESSEL INJURY

Laceration of the thoracic aorta or brachiocephalic vessels due to blu nt trauma is relatively common. In such cases, prompt and accurate dia gnosis followed by timely surgery is essential. These injuries typical ly occur at the aortic isthmus and can casually be readily identified at aortography, which remains the standard of reference for diagnosis. However, numerous anatomic variants that manifest as ''lumps'' or ''b umps'' on aortograms can mimic true vascular injury, thereby leading t o false-positive or false-negative diagnosis. These variants include a ortic 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 i sthmus and have smooth, uninterrupted margins with gently sloping shou lders. Infundibula are also smoothly marginated but can occur in a var iety of locations and generally taper into one or more vessels at thei r apex. Knowledge of the imaging appearances of these anatomic variant s is necessary for correct interpretation of aortograms of the aorta a nd brachiocephalic vessels in blunt trauma patients.