In young children, the great vessels, on conventional radio-graphs, are or can be obscured by the shadow of the thymus. As the thymus diminishes in size, the great vessels become more and more visible.
Imaging of the great vessels will mostly be done using CT and/or MRI. The use of diagnostic angiography should be considered to be obsolete.
Table 1.82 The great vessels, normal appearance
Normal aorta and pulmonary artery
In young children, the aorta is not always visible due to overlying thymic tissue.
The diameter of the aorta is influenced by respiration. In expiration, the aorta can enlarge and mimic a pathologic situation.
Normal superior vena cava
In children, the outline can be obscured by the thymus.
Table 1.83 The great vessels, pathologic changes of the aorta (size, shape, position)
Dilatation (aneurysm) of the ascending aorta
Dilated right-sided aorta shadow. Displacement of the superior border leads to an aortic knuckle.
The ascending aorta should not form a distinct shadow (i.e., be border-forming) below the age of 10 y.
Causes include congenital valvular aortic stenosis, aortic insufficiency, truncus arteriosus, and aneurysms.
Dilatation of the ascending aorta and main pulmonary artery.
Endovascular treatment with plugs (e.g., Amplatzer device) is a widely used technique. The device is visible on conventional radiographs. Dislocation, into the pulmonary circulation, may occur. Other techniques are endovascular coiling or transthoracic clipping.
Narrow vascular pedicle in transposition of the great vessels
Table 1.84 The large vessels, changes in contour of the pulmonary artery
Enlarged main pulmonary segment
Convex dilatation of the pulmonary vasculature.
Seen in pulmonary stenosis with poststenotic dilatation.
Small pulmonary artery (e.g., in tetralogy of Fallot)
The contour of the pulmonary artery is flat or concave.
Table 1.85 The great vessels, changes in contour of the superior mediastinal veins
Absent silhouette of the superior vena cava
“Empty” superior vena cava contour.
Due to “rotation” of the heart due to the enlarging right atrium.
Persistent left superior vena cava and duplicated superior vena cava
Widening of the left superior mediastinum.
Can be seen as an isolated anomaly.
TAPVD (type I)
Bilateral widening of the mediastinum superior.
Coronary Artery Disease
Compared to adults, coronary artery disease in children is a rare finding; however, with the advent of modern imaging techniques, the pediatric radiologist should be aware of the pathology of coronary arteries.
Table 1.86 Coronary artery disease
Abnormal origin and course of coronary arteries:
Absent left main trunk (split origination of left coronary artery)
Anomalous location of coronary ostium within aortic root or near proper aortic sinus
Anomalous location of coronary ostium outside normal aortic sinuses
Anomalous origination of the coronary ostium from opposite, facing “coronary” sinus
Single coronary artery.
The most common anomaly is an aberrant origin of the main left or right coronary artery from the wrong sinus of Valsalva.
Often an incidental finding during coronary angiography, with an estimated incidence of 0.3%–0.8%.
Anomalies of coronary arterial anatomy:
Congenital ostial stenosis or atresia (left coronary artery, left anterior descencing [LAD] artery, right coronary artery [RCA], circumflex coronary artery [Cx]
Coronary ectasia or aneurysm
Intramural coronary artery (muscular bridge)
Subendocardial coronary course
Anomalous origination of posterior descending artery from anterior descending branch or septal penetrating branch
Dilation, regional or over a longer trajectory, of the coronary arteries.
Can be seen in Kawasaki disease, LEOPARD syndrome (extremely rare).
First diagonal branch of LAD
Second diagonal branch of LAD
Left circumflex artery
Rings and Slings
A vascular ring is the result of anomalous development of the aortic arch. In the embryologic stage, the aorta forms a ring around the primitive foregut, and anomalous development leads to an aortic ring or sling.
Historically, the primary diagnostic tool was the contrast (barium) swallow; however, with the advent of CT and MRI, this technique has been superseded and should be considered obsolete.
In young children, the main presenting symptom may be stridor, often the result of concomittant tracheomalacia. Later in life, dysphagia is the most common symptom.
Table 1.87 Aberrant arteries and vascular rings
Anomalous vessels with posterior esophageal and anterior tracheal impression