Pictorial review of the pulmonary vasculature: from arteries to veins

Abstract

Pathology of the pulmonary vasculature involves an impressive array of both congenital and acquired conditions. While some of these disorders are benign, disruption of the pulmonary vasculature is often incompatible with life, making these conditions critical to identify on imaging. Many reviews of pulmonary vascular pathology approach the pulmonary arteries, pulmonary veins and bronchial arteries as individual topics. The goal of this review is to provide an integrated overview of the high-yield features of all major disorders of the pulmonary vasculature. This approach provides a more cohesive and comprehensive conceptualisation of respiratory pathology. In this review, we present both the salient clinical and imaging features of congenital and acquired disorders of the pulmonary vasculature, to assist the radiologist in identifying pathology and forming a robust differential diagnosis tailored to the presenting patient. TEACHING POINTS: • Abnormalities of the pulmonary vasculature are both congenital and acquired. • Pathology of a single pulmonary vascular territory often affects the entire pulmonary vasculature. • Anomalous pulmonary venous flow is named as a function of its location and severity. • Bronchial arteries often undergo dilatation secondary to cardio-respiratory pathology.

Keywords: Bronchial arteries; Diagnostic imaging; Pulmonary artery; Pulmonary medicine; Pulmonary veins.

Fig. 1

Our conceptual organisation of pulmonary vascular pathology

Fig. 2

Pulmonary artery atresia. a Axial CT image demonstrating abrupt termination of the main pulmonary artery (white arrow) in a patient with tetralogy of Fallot with a small hypoplastic distal pulmonary artery (white arrowhead). b Bronchial artery dilatation off the descending aorta occurs to feed the pulmonary vasculature (white arrows) with the hypoplastic distal pulmonary artery again demonstrated (white arrowhead)

Fig. 3

Pulmonary artery sling. Schematic (a) and axial contrast-enhanced CT image (b) show the left pulmonary artery (white arrow) arising from the right pulmonary artery, passing between the oesophagus (black arrowhead) and right mainstem bronchus (white arrowhead). c Coronal maximal intensity projection CT image shows compression of the proximal right mainstem bronchus (white arrowhead) by the aberrant left pulmonary artery (white arrow)

Fig. 4

Pulmonary artery measurement. a CT imaging demonstrating double oblique measurement technique through the main pulmonary artery. b Axial CT image demonstrating transverse measurement through the main pulmonary artery at the level of the right pulmonary artery bifurcation

Fig. 5

Pulmonary hypertension in a patient with idiopathic pulmonary fibrosis. a Axial CT image (lung window) shows basal and peripheral predominant fibrotic disease with reticulation and honeycombing extending to the subpleural surface, as well as traction bronchiectasis, consistent with usual interstitial pneumonia pattern of fibrosis in a patient with idiopathic pulmonary fibrosis. b Axial CT image shows dilatation of the main pulmonary artery, measuring up to 4.1 cm in maximal diameter

Fig. 6

Pulmonary hypertension in a patient with liver disease. a Coronal contrast-enhanced CT image shows sequela of portal hypertension secondary to cirrhotic liver morphology with splenomegaly (*), enlarged splenorenal collateral vessels (white arrows) and enlarged left renal vein (black arrow). b Axial contrast-enhanced CT image shows dilatation of the pulmonary arteries with the main pulmonary artery measuring up to 3.4 cm in maximal diameter

Fig. 7

Pulmonary artery aneurysm in a patient with Behçet’s disease. a Three-dimensional reconstruction from a contrast-enhanced CT scan showing a right lower lobe pulmonary artery aneurysm in a patient with Behçet’s disease (white arrow). Digital subtraction fluoroscopic images obtained before (b) and after (c) coil embolisation of the right lower lobe pulmonary aneurysm (white arrow)

Fig. 8

Pulmonary artery narrowing/obstruction. a Axial contrast-enhanced CT image shows a large, irregularly shaped filling defect within the left pulmonary artery (arrow) with extension into the mediastinal fat (arrowhead) causing intrinsic narrowing/obstruction of the pulmonary artery in a patient with biopsy proven angiosarcoma. b Coronal CT image demonstrating severe narrowing of the right upper lobe pulmonary artery (arrow) secondary to extrinsic mass effect from a right upper lobe primary lung malignancy. c Coronal CT image demonstrating complete occlusion of the right upper lobe pulmonary artery (arrow) secondary to extrinsic compression from biopsy proven fibrosing mediastinitis. Note the coarse calcifications present within the region of fibrosis (arrowheads)

Fig. 9

Two patients with acute pulmonary emboli. a Axial contrast-enhanced CT image shows a large saddle embolus of the main pulmonary artery (black arrow) as well as lobar/segmental involvement of the right and left pulmonary arteries (white arrows). b Axial contrast-enhanced CT image of another patient with bilateral acute pulmonary emboli demonstrate the central focal filling defect within bilateral segmental pulmonary arteries which is rimmed by contrast (*)

Fig. 10

Two patients with chronic pulmonary emboli. a Axial contrast-enhanced CT image shows a web-like filling defect within a segmental right lower lobe pulmonary artery consistent with chronic pulmonary embolus (white arrow). b Axial non-contrast CT image of another patient demonstrates linear calcification within the right interlobar pulmonary artery consistent with chronic pulmonary embolus (white arrow)

Fig. 11

Pulmonary venous variant. a Three-dimensional reconstruction of a contrast-enhanced CT shows normal pulmonary venous anatomy with two right and two left pulmonary veins draining into the left atrium. b Axial CT image showing the most common variant of pulmonary venous anatomy, a fusion of the left pulmonary veins prior to entry in the left atrium (*). c Three-dimensional reconstruction shows a fusion of the left superior and inferior pulmonary veins with a shared ostium (*)

Fig. 12

Partial anomalous pulmonary venous return. a Conceptual illustration of partial anomalous pulmonary venous return. b Axial contrast-enhanced CT of an adult patient with partial anomalous venous return of the right upper lobe (white arrow) with blood flow returning to the superior vena cava. c Double oblique contrast-enhanced CT of an adult patient with partial anomalous venous return of the left upper lobe (white arrow) with blood flow returning to the left brachiocephalic vein

Fig. 13

Scimitar syndrome. a Conceptual illustration of scimitar syndrome. b Coronal contrast-enhanced CT of an adult patient with scimitar syndrome showing the entire right lung pulmonary venous return (white arrows) draining into the inferior vena cava (black arrow)

Fig. 14

Pulmonary vein varix. Axial contrast-enhanced CT image demonstrated a pulmonary vein varix (white arrow); note its proximity to the insertion in the left atrium. Varices can be saccular, tortuous, or confluent, with confluent being the most common

Fig. 15

Pulmonary venous thrombus. Axial contrast-enhanced CT image in a patient with non-small cell lung cancer demonstrating a filling defect within the left superior pulmonary vein (white arrow). Note extensive lymphadenopathy within the left hila and mediastinum (*) from metastatic involvement

Fig. 16

Pulmonary venous collaterals. a Axial contrast-enhanced CT image demonstrates upper right lobe squamous cell carcinoma (*) with metastatic disease obstructing the superior vena cava and stent (black arrow). Note extensive collateral formation (white arrows). b Axial CT image showing high-density contrast flow into the pulmonary venous system (black arrow) secondary to collateral formation (white arrows) with a right-to-left shunt in the setting of superior vena cava obstruction

Fig. 17

Pulmonary arteriovenous malformation. a Conceptual illustration of simple versus complex arteriovenous malformation. Axial (b, c) and coronal (d) contrast-enhanced CT images demonstrate a large arteriovenous malformation of the left upper lobe (arrowhead) with a clearly identifiable feeding pulmonary artery (solid arrow) and draining pulmonary vein (dotted arrow). e Axial contrast-enhanced CT images of the same patient in lung windows reinforces the importance of fully evaluating the entire lungs as additional smaller AVMs (circle) were also identified in this patient leading to the diagnosis of hereditary haemorrhagic telangiectasia

Fig. 18

Pulmonary sequestration. a Conceptual illustration of extralobar and intralobar sequestration. Note that extralobar sequestration involves venous drainage into the azygos system forming a left-to-right shunt while intralobar sequestration involves pulmonary venous drainage forming a left-to-left shunt. b Axial CT demonstrating an asymptomatic oval lesion (white arrow) in the left lower lobe consistent with extralobar sequestration in a 23-year-old woman. Blood supply is derived from the abdominal aorta with venous drainage occurring via the azygos system. Double oblique CT MIP images (c, d) and coronal CT MPR image (e) demonstrating an intralobar sequestration located within the pleura of the left lower lobe. Note the aberrant arterial supply to the lateral left lower lobe below the level of the diaphragm (black arrows) which extends through the diaphragm into the tissues of the left lower lobe (white arrows). Venous drainage of this intralobar sequestration is via the pulmonary venous system (arrowheads)

Fig. 19

Bronchial artery anatomy. Coronal CT of the chest shows a dilated right bronchial artery (5 mm) arising from the intercostal bronchial artery trunk (ICBAT) (white arrow) of the postero-lateral thoracic aorta at the level of T6. Please note that the normal bronchial artery is less than 2 mm in diameter. While ICBAT origin is the most typical of the right bronchial artery, the left bronchial arteries usually arise directly from the aorta

Fig. 20

Bronchial artery dilatation. a Axial CT image showing congenital absence of the right lower lobe pulmonary artery (white arrow). b Axial CT image showing 9.0 mm dilated bronchial artery supplying the right lower lobe (black arrow)

Fig. 21

Bronchial artery bleeding. Pre- (a) and post-contrast (b) axial images in a patient with pneumonia and new onset haemoptysis demonstrates a blush of contrast within the right lower lobe consolidation concerning for active bleeding (arrow). Bronchial arteriogram demonstrates a blush of contrast (arrow) confirming bleed pre embolisation (c) with resolution of the contrast blush post embolisation (d)