Chapter30 Aorta

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Chapter 30: Thoracic Aorta

Figure 30.18.  Type B Interrupted Aortic Arch. 3D VR shows a type B interrupted aorta arch with the ascending aorta ( dashed yellow arrow ) giving rise to the right brachiocephalic artery ( yellow arrow- head ) and left common carotid artery (LCCA, white arrowhead ). The aortic arch is absent, or interrupted, after the origin of the LCCA ( white arrow ). The left subclavian artery ( dashed white arrow ) arises from the descending thoracic aorta which received flow through a large patent ductus arteriosus ( yellow arrow ).

brachiocephalic and left common carotid origins. Type B is most common (50% to 60%) and is associated with VSD, bicuspid aortic valve, and left ventricular outflow tract anom- alies (Fig. 30.18). All types require a patent ductus arteriosus for survival. Methods of surgical repair are similar to those of aortic coarctation, described below. Please see “Postoperative Aorta” section for further discussion. Circumflex Aorta Circumflex aorta is an extremely rare anomaly which can occur with either a left- or right-sided aortic arch. The aortic arch travels posteriorly as usual but crosses the midline behind the esophagus, above the tracheal carina at the level of the distal arch/descending thoracic aorta, and continues distally Figure 30.17.  Cervical Arch With Aberrant Left Subclavian Artery. Coronal oblique MIP CT image shows the ascending aorta extending high into the right supraclavicular region ( red arrows ) with a right- sided cervical arch ( yellow arrow ). Similar to other right arches with an aberrant subclavian artery, the first vessel of the aorta is the left common carotid artery ( yellow arrowheads ) followed by the right common carotid artery ( white arrow ) and right subclavian artery (not visualized). The last branch off the aorta is the aberrant left subcla- vian artery ( black arrow ), the origin of which is not visualized in this view. (Courtesy of David Godwin, MD.)

contralateral to the aortic arch side (Fig. 30.19). A vascular ring can be present depending on the location of the ductus arteriosus.

Descending Thoracic Aorta The descending thoracic aorta begins after the ligamentum arteriosum and transitions to the abdominal aorta after pass- ing through the diaphragmatic hiatus. The descending tho- racic aorta gives rise to multiple systemic vessels, including the intercostal and bronchial arteries. Aortic Coarctation Aortic coarctation is defined as focal narrowing of the aorta adjacent to the ductus arteriosus (i.e., juxtaductal) and often occurs with varying degrees of aortic arch hypoplasia. In very rare instances, it can involve the abdominal aorta. Aor- tic coarctation is a relatively common anomaly, representing

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Figure 30.19.  Circumflex Aortic Arch. Sequential axial MR GRE images demonstrate a right-sided arch (*) which passes behind the esophagus before continuing as a left-sided descending thoracic aorta.