Imaging Sciences Interesting Cases
Case 87
Charles Hubeny, MD
Clinical Presentation: Patient is a 12-year-old male with dysphagia and wheezing.
Imaging Findings: Double aortic arch.
 |
| Figure 1: Frontal chest radiograph demonstrates right-sided aortic knob indenting the right wall of the trachea. |
 |
| Figure 2: AP and left lateral views during fluoroscopic examination of the esophagus show right and posterior indentations on the esophagus from the vascular ring. |
 |
| Figure 3: Axial T1 image through the lung apices shows the “four vessel sign”. |
|
| Figure 4: Axial T1 slice through the level of the arches demonstrates complete vascular ring with constriction of the esophagus and trachea. The right-sided aortic arch is dominant while the left arch is smaller. |
 |
| Figure 5: 3D MRI image looking at the ring from a left posterior view shows the complete vascular ring with the origins of the each common carotid and subclavian artery off of each arch. |
Diagnosis: Double Aortic Arch
Discussion: Vascular rings are uncommon and make up 1% of congenital heart defects although true incidence is not known as some individuals are asymptomatic. Rings form when the embryologic process of pharyngeal arch artery regression and persistence does not occur normally resulting in an encompassed trachea and esophagus. Double aortic arch is the most common vascular ring making up 55% of cases.
The double aortic arch results from bilateral persistence of the fourth embryonic aortic arch. In most individuals the right arch is larger (dominant) while the left arch may be smaller or atretic with a fibrotic remnant. Both arches join the descending thoracic aorta posteriorly encircling the trachea and esophagus. Each arch gives rise to carotid and subclavian arteries resulting in the “four vessel sign” seen on cross sectional imaging.
There are no specific genetics in isolated arch anomalies as cases occur sporadically but they can be associated with congenital heart disease (tetrology of Fallot, truncus arteriosus, transposition of the great vessels), or heart defects in VACTERL or CHARGE associations.
Findings include tracheal deviation from the dominant arch seen on a frontal chest radiograph. Fluoroscopic examination of the esophagus shows an indentation of the esophagus posteriorly with anterior compression of the trachea. Cross sectional imaging is used for per-surgical planning where there is direct visualization of the anomaly.
Differential diagnosis includes right arch with aberrant left subclavian, left pulmonary artery sling, innominate artery compression syndrome, or mediastinal mass. These differentials can usually be excluded with radiography or fluoroscopy but cross sectional imaging is needed to differentiate right arch with aberrant left subclavian from double aortic arch.
Symptoms usually occur early in life soon after birth with feeding intolerance or stridor that worsens with feeding. Dysphagia, barking cough, and apnea are typical symptoms in children.
If there is significant respiratory compromise then treatment includes thoracotomy with division of less dominant arch. Complications include persistent dysphagia or airway compression, tracheobronchomalacia, and rarely aortoesophageal fistula.
References:
- Backer CL: Vascular rings and pulmonary artery sling. In: Mavroudis C, Backer CL ed. Pediatric Cardiac Surgery. 3rd ed. Philadelphia, Mosby. 234-250, 2003.
- Fleck RJ, Pacharn P, Fricke BL, Ziegler MA, Cotton RT, Donnelly LF: Imaging findings in pediatric patients with persistent airway symptoms after surgery for double aortic arch. AJR Am J Roentgenol. 2002 May;178(5):1275-9. [PubMed]