Chapter30 Aorta

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Section V: Cardiac Radiology

A

Figure 30.11.  Left Arch and Aberrant Right Subclavian Artery. Axial ( A ) and sagittal CT ( B ) demonstrate the right subclavian artery arising from the distal arch ( arrow ) which indents the posterior esophagus cor- responding to the aberrant right subclavian artery. This is a common ana- tomic variant that leads to no symptoms in the vast majority of patients.

B

by a rounded soft tissue structure abutting and indenting the inferior aspect of the right trachea (Fig. 30.12). Right aortic arch can have variable arch branching pat- terns, but the most common are aberrant left subclavian artery and mirror-image branching. In right arch with aber- rant left subclavian artery, the first branch from the aortic arch is the left common carotid artery, followed by the right carotid artery, right subclavian artery, and the aberrant left subclavian artery. The left subclavian artery passes posterior

*

Figure 30.13.  Right Arch and Aberrant Left Subclavian Artery. Axial CT scan in a patient with dysphagia shows a right aortic arch (*). The first vessel off the arch is the left common carotid artery ( black arrowhead ). The right common carotid and right subclavian arteries, which are the second and third vessels off the arch, respectively, are not seen on this image. The last vessel off the arch is the aberrant left subclavian artery ( yellow arrow ). This vessel courses posterior to the esophagus ( white arrow ) and trachea via a large 3.5-cm diverticulum of Kommerell ( black arrow ) which compresses the esophagus and slightly narrows the trachea. A left ligamentum arteriosum, which is not usually visualized, forms a vascular ring that can cause symptoms.

Figure 30.12.  Right Arch. PA chest radiograph with a right aortic arch ( arrows ) indenting the right lateral aspect of the distal trachea.