Congenital anomalies of the pulmonary arteries: an imaging overview

Abstract

Congenital pulmonary artery anomalies represent a diverse group of abnormalities, ranging from asymptomatic incidental findings to causes of sudden cardiac death. While some may be recognized in childhood, others may be found incidentally in adulthood. We review the clinical and imaging findings in patients with congenital anomalies of the pulmonary arteries, including valvular and perivavular anomalies as well as abnormal narrowing, course and communications of the pulmonary arteries. We also discuss the role of various imaging modalities in the evaluation of these patients. It is vital to be aware of the key radiologic manifestations and associated haemodynamic consequences in these conditions in order to facilitate accurate diagnosis and prognostic stratification.

Figure 1.

Congenital pulmonic stenosis. (A) Frontal chest radiograph in a young adult showing classic asymmetric enlargement of the left PA and main PA (circle). (B) Contrast-enhanced sagittal CT showing congenital pulmonic stenosis with large aneurysmal dilatation of the main PA (*) resulting in displacement of the LAD coronary artery (arrow). (C) Same patient as (B) status post pulmonary valve replacement and resection of PA aneurysm. Notice resolved displacement of the LAD (arrow). LAD, left anterior descending; PA, pulmonary artery.

Figure 2.

Absent pulmonary valve in a 19-day-old infant. (A) Contrast-enhanced axial CT shows marked enlargement of the pulmonary arteries (*), compression of the bronchial structures (arrows) and left lower lobe collapse. (B) Virtual bronchoscopy and volume rendered image of the airway in the same patient showing severe narrowing of the carina and right mainstem bronchus (arrows).

Figure 3.

Bicuspid and quadricuspid pulmonary valve. (A) Phase contrast MR in a patient with TOF demonstrating a bicuspid pulmonary valve (arrow). (B) Double oblique images from a contrast-enhanced CT shows a quadricuspid pulmonary valve (arrow) incidentally noted in a 67-year-old male. Note the asymmetry in size, with a smaller right posterolateral leaflet (arrowhead). TOF, tetralogy of Fallot.

Figure 4.

PIPA in two patients. (A) Contrast-enhanced axial CT images show left PIPA, with associated right aortic arch and multiple bronchial and intercostal collaterals (arrows). The left PA is completely atretic and not visualized. (B) Lung windows in the same patient as (A) demonstrate thickened, serrated pleura, subpleural bands, and interlobular septal thickening (arrow) due to transpleural collaterals. (C) Repaired right PIPA with a main pulmonary trunk to branch PA graft. A proximal stenosis of the graft developed requiring stenting (arrow), but severe stenosis of the distal anastomosis of the shunt is now present (arrowhead). PA, pulmonary artery; PIPA, proxima linterruption of the pulmonary artery.

Figure 5.

PA-VSD in a 5-year-old girl. (A) Contrast-enhanced axial CT images show pulmonary atresia (arrow) and MAPCAs (arrowheads). Notice the large caliber of the aorta, a common finding in patients with TOF spectrum (*). (B) 3D volume rendered image demonstrating the large MAPCAs (arrows). 3D, three-dimensional; MAPCAs, major aortopulmonary collateral arteries; PA-VSD, pulmonary atresia with ventricular septal defect; TOF, tetralogy of Fallot.

Figure 6.

PA-IVS status post Glenn and Fontan repair. (A) Contrast-enhanced axial CT images show a hypoplastic and hypertrophied RV (*), intact ventricular septum (arrow), (B) marked hypoplasia of the main PA (arrow), and (C) coronary sinusoids (arrow). Coronary sinusoids (ventriculo-coronary connections) may form due to the RV hypertension, may be associated with coronary stenosis, and contribute to morbidity. PA, pulmonary artery; PA-IVS, pulmonary atresia with intact ventricular septum; RV, right ventricle.

Figure 7.

Pulmonary branch stenosis in a patient with TOF. (A) Axial MR angiography shows severe left PA stenosis (arrow). (B) Fused phase contrast and magnitude image shows region of interest over the left PA (arrow). Phase contrast imaging can be used to assess differential flow. This patient had 88% right PA and 12% left PA flow. PA, pulmonary artery; TOF, tetralogy of Fallot.

Figure 8.

Pulmonary sling with complete tracheal cartilaginous rings in a 6-month-old infant. (A) Contrast-enhanced CT shows the left PA (arrow) originating from the right PA and coursing between the trachea and oesophagus. (B) Volume rendered images in the same patient show a long segment tracheal narrowing (arrow) and a low T-shaped carina (arrowhead). PA, pulmonary artery.

Figure 9.

Partial anomalous left PA. (A) Contrast-enhanced axial CT showed the left lower lobe PA (arrow) arising from the right PA and coursing posterior to the trachea, creating a sling. (B) 3D volume rendered images show resultant narrowing of the trachea (arrow). Case courtesy Monica Ocampo, MD. 3D, three-dimensional; PA, pulmonary artery.

Figure 10.

ALCAPA in a 51-year-old female. Contrast-enhanced axial CT images show the left coronary artery (arrow) arising from the pulmonary trunk and a large caliber of both the right (arrowhead) and left coronary arteries. ALCAPA, anomalous left coronary artery from the pulmonary artery.

Figure 11.

PAVF/PAVM in a 55-year-old male. Contrast-enhanced axial (A–C) and sagittal (D) CT images show a left PA to left upper pulmonary vein fistula (arrows). PAVF, pulmonary arteriovenous fistula; PAVM, pulmonary arteriovenous malformation.