1. Introduction
Pulmonary artery stenosis (PAS) is caused by the formation of obstructive lesions in the pulmonary artery and its branches. Due to the decrease of cross-sectional area of pulmonary artery, the blood flow was impeded exiting the heart. This may raise the pressure of right ventricle (RV), which can cause the endothelial damage of PA and further lead to pulmonary artery hypertension (PAH). With all the causes, presenting as right heart failure can lead to bad prognosis and even death [
1].
PAS can be categorized based on location. And there are four types of PAS, from proximal to sub-segmental. TypeⅠinvolves single central stenosis of the main pulmonary trunk or branches of the pulmonary artery. TypeⅡinvolves the bifurcation of the pulmonary artery. Type Ⅲ involves multiple peripheral stenosis. Type Ⅳ involves a combination of both main and peripheral stenosis [
2].
The clinical presentation of PAS varies from shortness of breath, fatigue, tachycardia to the swelling of the feet, ankles, and abdomen which happen in the advanced stage, as a result of right heart failure. Thus, it is important to detect PAS as early as possible to improve the prognosis.
When the patient was present with those symptoms, chest radiography or computed tomography should be conducted. High resolution computed tomography (HRCT) and computed tomography pulmonary angiography (CTPA) are invaluable for examining the pulmonary vessels, which can provide details of the lumen, vessel wall, adjacent mediastinal structures and subsequent lung lesions, which are very important to identify the reasons of PAS.
The aim of this article is to review the imaging features of congenital and acquired anomalies which cause the stenosis of pulmonary artery, and to illustrate the typical CT characteristics of these anomalies. We will discuss the congenital diseases cause the decrease of right ventricular output volume, pulmonary artery and pulmonary vein atresia. To simplify the understanding, the acquired diseases will be categorized as anomalies affecting the vessel wall, intraluminal anomalies and extraluminal anomalies.
Table 1 provides the content of these disease categorized by the reasons of PAS.
Figure 1.
Pulmonary valvular stenosis- bicuspid pulmonary valve. A: chest radiograph shows the prominence of left pulmonary artery and the right pulmonary artery (arrow) and hilum appear normal. B-C and D-E: belong to two different patients, but both show the stenotic bicuspid pulmonary valve (arrow) and poststenotic dilation of the main and left pulmonary artery, whereas the distal branches are relatively small. The jet of blood flow (arrow) forces through the stenotic valve to the left pulmonary artery on E. F: Volumeb rendering of pulmonary arteries indicate the poststenotic dilation of the main and left pulmonary artery.
Figure 1.
Pulmonary valvular stenosis- bicuspid pulmonary valve. A: chest radiograph shows the prominence of left pulmonary artery and the right pulmonary artery (arrow) and hilum appear normal. B-C and D-E: belong to two different patients, but both show the stenotic bicuspid pulmonary valve (arrow) and poststenotic dilation of the main and left pulmonary artery, whereas the distal branches are relatively small. The jet of blood flow (arrow) forces through the stenotic valve to the left pulmonary artery on E. F: Volumeb rendering of pulmonary arteries indicate the poststenotic dilation of the main and left pulmonary artery.
Figure 2.
Pulmonary artery atresia with ventricular septal defect. A: Coronal CT angiography shows that the main pulmonary artery was atretic and right pulmonary artery was slender (arrow). B: Oblique coronal CT shows outlet ventricular septal defect (arrow) and overriding aorta (AO). C: Oblique coronal CT demonstrates patent ductus arteriosus (arrow) originating from aorta to left pulmonary artery.
Figure 2.
Pulmonary artery atresia with ventricular septal defect. A: Coronal CT angiography shows that the main pulmonary artery was atretic and right pulmonary artery was slender (arrow). B: Oblique coronal CT shows outlet ventricular septal defect (arrow) and overriding aorta (AO). C: Oblique coronal CT demonstrates patent ductus arteriosus (arrow) originating from aorta to left pulmonary artery.
Figure 3.
Unilateral Pulmonary vein atresia. A: coronal CTA shows the absent of right pulmonary veins and without outpouchings on the left atrium (arrow). B-C: MIP and lung windowing coronal CT images show mass-like soft-tissue within the right hilum (arrow in B), the septal lines and bronchial wall thickening (arrow in C) which indicates the engorged lymphatics and collateral venous channels. D: VR of CTA shows the small caliber of right pulmonary arteries. CTA-computed tomography angiography, MIP-maximum-intensity projection, VR-volume rendering.
Figure 3.
Unilateral Pulmonary vein atresia. A: coronal CTA shows the absent of right pulmonary veins and without outpouchings on the left atrium (arrow). B-C: MIP and lung windowing coronal CT images show mass-like soft-tissue within the right hilum (arrow in B), the septal lines and bronchial wall thickening (arrow in C) which indicates the engorged lymphatics and collateral venous channels. D: VR of CTA shows the small caliber of right pulmonary arteries. CTA-computed tomography angiography, MIP-maximum-intensity projection, VR-volume rendering.
Figure 4.
Pulmonary thromboembolism. A: Axial CT images shows a partial filling defects in the left and right pulmonary arteries, which is non-enhanced and surrounded with contrast (arrow). B: Axial CT image shows the enlargement of right ventricle and atrium (RV:LV ratio >1) and 3D volume rendering image (C) shows the range of thrombus which is marked with red colors. D: Axial CT image shows the complete filling defects of another patient, which presents no enhancement of the entire lumen (arrow) and subpleural pulmonary infarction. E: Axial CT image of another patient who underwent the thrombolytic therapy shows the partial filling defects in pulmonary artery. F: After 4 months treatment, there are some band-like enhancements (arrow) in the thrombus which means thrombolysis. LV-left ventricle, RV-right ventricle.
Figure 4.
Pulmonary thromboembolism. A: Axial CT images shows a partial filling defects in the left and right pulmonary arteries, which is non-enhanced and surrounded with contrast (arrow). B: Axial CT image shows the enlargement of right ventricle and atrium (RV:LV ratio >1) and 3D volume rendering image (C) shows the range of thrombus which is marked with red colors. D: Axial CT image shows the complete filling defects of another patient, which presents no enhancement of the entire lumen (arrow) and subpleural pulmonary infarction. E: Axial CT image of another patient who underwent the thrombolytic therapy shows the partial filling defects in pulmonary artery. F: After 4 months treatment, there are some band-like enhancements (arrow) in the thrombus which means thrombolysis. LV-left ventricle, RV-right ventricle.
Figure 5.
Chronic pulmonary embolism. A: Axial CT image shows bilateral eccentric laminated filling defects and pulmonary arteries stenosis in the pulmonary arteries (arrows) in a patient with chronic pulmonary embolism. B: Coronal reconstruction CTA image in another patient with dyspnea shows a web (arrows) or band within a right lower lobar pulmonary artery, consistent with chronic PE. C: Coronal reconstruction CTA image in a patient with history of acute PE shows calcified obstructive thrombus (arrows) within bilateral pulmonary arteries. CTA-computed tomography angiography, PE-pulmonary embolism.
Figure 5.
Chronic pulmonary embolism. A: Axial CT image shows bilateral eccentric laminated filling defects and pulmonary arteries stenosis in the pulmonary arteries (arrows) in a patient with chronic pulmonary embolism. B: Coronal reconstruction CTA image in another patient with dyspnea shows a web (arrows) or band within a right lower lobar pulmonary artery, consistent with chronic PE. C: Coronal reconstruction CTA image in a patient with history of acute PE shows calcified obstructive thrombus (arrows) within bilateral pulmonary arteries. CTA-computed tomography angiography, PE-pulmonary embolism.
Figure 6.
In situ thrombosis in pulmonary hypertension in a 16-year-old girl with primary pulmonary hypertension. A and B: Axial and coronal CTA image show concentric, broad-based filling defects within massively dilated right pulmonary artery and the lumen (blood filing) is narrowed locally (arrow). The main and the left pulmonary arteries are also enlarged. C: Cross section of left pulmonary artery in MPR imaging show interface irregularities (arrow) of the thrombosis within the symmetric widening and smooth outline of the vessel, which rule out compression caused by mass effect. CTA-computed tomography angiogrpahy, MPR-multiplanar reformation.
Figure 6.
In situ thrombosis in pulmonary hypertension in a 16-year-old girl with primary pulmonary hypertension. A and B: Axial and coronal CTA image show concentric, broad-based filling defects within massively dilated right pulmonary artery and the lumen (blood filing) is narrowed locally (arrow). The main and the left pulmonary arteries are also enlarged. C: Cross section of left pulmonary artery in MPR imaging show interface irregularities (arrow) of the thrombosis within the symmetric widening and smooth outline of the vessel, which rule out compression caused by mass effect. CTA-computed tomography angiogrpahy, MPR-multiplanar reformation.
Figure 7.
Tumor embolism (benign). A: Sagittal MPR image in a patient with intravenous leiomyomatosis shows tumor embolism in the main pulmonary artery. B: Coronal MPR image shows the tumor originates from uterus, along the left ovarian vein-left renal vein-inferior vena cava-right atrium-right ventricle and then extend into pulmonary artery (arrows). C. Photograph of the resected tumor. MPR-multiplanar reformation.
Figure 7.
Tumor embolism (benign). A: Sagittal MPR image in a patient with intravenous leiomyomatosis shows tumor embolism in the main pulmonary artery. B: Coronal MPR image shows the tumor originates from uterus, along the left ovarian vein-left renal vein-inferior vena cava-right atrium-right ventricle and then extend into pulmonary artery (arrows). C. Photograph of the resected tumor. MPR-multiplanar reformation.
Figure 8.
Tumor embolism and PTTM. A: Coronal CT MPR image in a patient with right lung cancer shows tumor emboli in the subsegmental pulmonary arterial branches (arrows) and the lumen occlusion. B: Coronal CT scan image at the same level with soft tissue windowing shows the vascular dilatation and beading of subsegmental arteries of the right pulmonary artery (arrows). C: CT in another patient with right atrium tumor shows tumor emboli with a tree-in-bud appearance within secondary lobule arteries (short arrow) and beading of subsegmental arteries (long arrow), which indicate PTTM.
Figure 8.
Tumor embolism and PTTM. A: Coronal CT MPR image in a patient with right lung cancer shows tumor emboli in the subsegmental pulmonary arterial branches (arrows) and the lumen occlusion. B: Coronal CT scan image at the same level with soft tissue windowing shows the vascular dilatation and beading of subsegmental arteries of the right pulmonary artery (arrows). C: CT in another patient with right atrium tumor shows tumor emboli with a tree-in-bud appearance within secondary lobule arteries (short arrow) and beading of subsegmental arteries (long arrow), which indicate PTTM.
Figure 9.
Septic pulmonary embolism in a 29-year-old woman with PDA and infective endocarditis. A and B: Sagittal and axial CTPA images demonstrate a filling defect within the main pulmonary artery (long arrow)-at the end of PDA (short arrow). C: Axial CTPA on lung windowing shows subpleural opacity, consistent with peripheral infarction (arrow) which may be caused by the septic emboli. CTPA-computed tomography pulmonary angiography, PDA-patent ductus arteriosus.
Figure 9.
Septic pulmonary embolism in a 29-year-old woman with PDA and infective endocarditis. A and B: Sagittal and axial CTPA images demonstrate a filling defect within the main pulmonary artery (long arrow)-at the end of PDA (short arrow). C: Axial CTPA on lung windowing shows subpleural opacity, consistent with peripheral infarction (arrow) which may be caused by the septic emboli. CTPA-computed tomography pulmonary angiography, PDA-patent ductus arteriosus.
Figure 10.
Pulmonary cement embolism. A and B: axial CTPA and coronal MIP shows the cement embolus (high density) in the pulmonary arteries of right and left upper lobes. C: cement in the vertebral body and the external vertebral venous plexuses. CTPA- computed tomography pulmonary angiography, MIP-maximum-intensity projection.
Figure 10.
Pulmonary cement embolism. A and B: axial CTPA and coronal MIP shows the cement embolus (high density) in the pulmonary arteries of right and left upper lobes. C: cement in the vertebral body and the external vertebral venous plexuses. CTPA- computed tomography pulmonary angiography, MIP-maximum-intensity projection.
Figure 11.
Catheter-related thrombosis in a patient post-CABG. A. Axial CTA image shows filling defects extend from the main pulmonary to right pulmonary artery along with the catheter. B. Coronal CTA image shows the thrombus wrap around the catheter (arrow). C. Maximum-intensity projection image shows the path of the catheter and the peripheral consolidation, which is consistent with pulmonary infarction (arrows). CABG-coronary artery bypass grafting, CTA-computed tomography angiography.
Figure 11.
Catheter-related thrombosis in a patient post-CABG. A. Axial CTA image shows filling defects extend from the main pulmonary to right pulmonary artery along with the catheter. B. Coronal CTA image shows the thrombus wrap around the catheter (arrow). C. Maximum-intensity projection image shows the path of the catheter and the peripheral consolidation, which is consistent with pulmonary infarction (arrows). CABG-coronary artery bypass grafting, CTA-computed tomography angiography.
Figure 12.
Pulmonary artery sarcoma with extensive involvement of the main pulmonary artery and into the right trunk. A: Contrast-enhanced CT showing a soft tissue mass filling the main and left pulmonary arteries (arrow). B: The filling defects shows delayed enhancement.
Figure 12.
Pulmonary artery sarcoma with extensive involvement of the main pulmonary artery and into the right trunk. A: Contrast-enhanced CT showing a soft tissue mass filling the main and left pulmonary arteries (arrow). B: The filling defects shows delayed enhancement.
Figure 13.
Vasculitis-ralated pulmonary artery thrombosis. Takayasu arteritis in a 33-year-old woman with dizziness and chest compress. A: Contrast-enhanced axial CT demonstrates filling defect and occlusion of the right pulmonary artery wall (arrow) and the main pulmonary is dilated. B: Axial CT image shows the wall of right subclavian artery and right common carotid artery are thickening and the lumen is narrow (arrow). C: Coronal MIP contrast-enhanced MRA image shows the right brachicephalic artery, right subclavian artery and right common carotid artery are stenosis or occlusion, right pulmonary artery and distal segment are stenosis. D: Axial MR T1 image shows mild thickening of the right pulmonary artery (long arrow) and iso-intensity thrombosis (short arrow). MIP-maximum-intensity projection, MRA-magnetic resonance angiography.
Figure 13.
Vasculitis-ralated pulmonary artery thrombosis. Takayasu arteritis in a 33-year-old woman with dizziness and chest compress. A: Contrast-enhanced axial CT demonstrates filling defect and occlusion of the right pulmonary artery wall (arrow) and the main pulmonary is dilated. B: Axial CT image shows the wall of right subclavian artery and right common carotid artery are thickening and the lumen is narrow (arrow). C: Coronal MIP contrast-enhanced MRA image shows the right brachicephalic artery, right subclavian artery and right common carotid artery are stenosis or occlusion, right pulmonary artery and distal segment are stenosis. D: Axial MR T1 image shows mild thickening of the right pulmonary artery (long arrow) and iso-intensity thrombosis (short arrow). MIP-maximum-intensity projection, MRA-magnetic resonance angiography.
Figure 14.
Vasculitis-related pulmonary artery thrombosis. Behcet syndrome (10 years) in a 40-year-old man with hemoptysis. A,B: Axial and coronary CT MPR images show aneurysmal dilatation of bilateral lower lobe pulmonary artery with wall thickening and enhancement (long arrows), in situ thrombosis and stenosis or occlusion. In situ thrombosis also can be found in right ventricle (short arrow in A). MPR-multiplanar reformation.
Figure 14.
Vasculitis-related pulmonary artery thrombosis. Behcet syndrome (10 years) in a 40-year-old man with hemoptysis. A,B: Axial and coronary CT MPR images show aneurysmal dilatation of bilateral lower lobe pulmonary artery with wall thickening and enhancement (long arrows), in situ thrombosis and stenosis or occlusion. In situ thrombosis also can be found in right ventricle (short arrow in A). MPR-multiplanar reformation.
Figure 15.
SMJS. 71Y woman with Swyer-James-Macleod syndrome. A: lung window axial CT shows the bronchiectasis and infections in right and left lower lobes (arrow), and the hyperlucent right lung. B: coronal MIP of CTPA shows the hypoplasia of the pulmonary vasculature of left lung. CTPA-computed tomography pulmonary angiography, MIP-maximum-intensity projection.
Figure 15.
SMJS. 71Y woman with Swyer-James-Macleod syndrome. A: lung window axial CT shows the bronchiectasis and infections in right and left lower lobes (arrow), and the hyperlucent right lung. B: coronal MIP of CTPA shows the hypoplasia of the pulmonary vasculature of left lung. CTPA-computed tomography pulmonary angiography, MIP-maximum-intensity projection.
Figure 16.
Aortic dissection. A and B: Sagittal and coronal CTA shows the hematoma of aortic dissection extending to the pulmonary artery via PDA (white arrow), which causes the stenosis of PA (red arrow). C: another patient of aortic dissection presents with the stenosis of right pulmonary artery (red arrow), because the discontinuity of the media. CTA-computed tomography angiography PDA- patent ductus arteriosus.
Figure 16.
Aortic dissection. A and B: Sagittal and coronal CTA shows the hematoma of aortic dissection extending to the pulmonary artery via PDA (white arrow), which causes the stenosis of PA (red arrow). C: another patient of aortic dissection presents with the stenosis of right pulmonary artery (red arrow), because the discontinuity of the media. CTA-computed tomography angiography PDA- patent ductus arteriosus.
Figure 17.
TB-FM. A: Coronal MIP shows the dense and calcified tissues wrapped the pulmonary vasculatures cause stenosis and the atelectasis of right middle lobe (arrow). B and C: the coronal MIP and MinIP shows the same segment of bronchus and pulmonary vessels (arrows) were affected by the tissues. MIP-maximum-intensity projection, MinIP-minimum-intensity projection.
Figure 17.
TB-FM. A: Coronal MIP shows the dense and calcified tissues wrapped the pulmonary vasculatures cause stenosis and the atelectasis of right middle lobe (arrow). B and C: the coronal MIP and MinIP shows the same segment of bronchus and pulmonary vessels (arrows) were affected by the tissues. MIP-maximum-intensity projection, MinIP-minimum-intensity projection.
Figure 18.
IgG4-related FM. 3D volume rendering image (A) of pulmonary arteries and MIP (B) show the stenosed proximal segment of right and left pulmonary arteries which were caused by the infiltrative soft tissue, without calcification (arrow). MIP-maximum-intensity projection.
Figure 18.
IgG4-related FM. 3D volume rendering image (A) of pulmonary arteries and MIP (B) show the stenosed proximal segment of right and left pulmonary arteries which were caused by the infiltrative soft tissue, without calcification (arrow). MIP-maximum-intensity projection.
Figure 19.
Tumor in a 50 years old male with lung cancer. A and B: Axial MIP presents that the tumor infiltrates and compresses the pulmonary arteries of left lung, following the lumen narrowing (arrow). C: sagittal view shows the occluded bronchus (arrow). D: the enlarged lymph nodes (arrows) on coronal CT due to metastasis. MIP-maximum-intensity projection.
Figure 19.
Tumor in a 50 years old male with lung cancer. A and B: Axial MIP presents that the tumor infiltrates and compresses the pulmonary arteries of left lung, following the lumen narrowing (arrow). C: sagittal view shows the occluded bronchus (arrow). D: the enlarged lymph nodes (arrows) on coronal CT due to metastasis. MIP-maximum-intensity projection.
Figure 20.
Aortic aneurysm. A and B: Coronal and sagittal MIP show the direct compression of left pulmonary arteries by the giant aortic aneurysm (arrow). MIP-maximum-intensity projection.
Figure 20.
Aortic aneurysm. A and B: Coronal and sagittal MIP show the direct compression of left pulmonary arteries by the giant aortic aneurysm (arrow). MIP-maximum-intensity projection.
Figure 21.
Radiofrequency ablation of atrial fibrillation. A: Axial CTA shows beaklike narrowing of the left superior pulmonary vein (arrow). B: Axial CTA shows the occluded inferior pulmonary vein (arrow). C: Coronal MIP shows the slender of left pulmonary arteries due to the decreased blood flow (arrows). MIP-maximum-intensity projection.
Figure 21.
Radiofrequency ablation of atrial fibrillation. A: Axial CTA shows beaklike narrowing of the left superior pulmonary vein (arrow). B: Axial CTA shows the occluded inferior pulmonary vein (arrow). C: Coronal MIP shows the slender of left pulmonary arteries due to the decreased blood flow (arrows). MIP-maximum-intensity projection.
Table 1.
Causes of pulmonary artery stenosis.
Table 1.
Causes of pulmonary artery stenosis.
CONGENITAL DISEASE |
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Pulmonary valvular stenosis |
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Pulmonary artery atresia |
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Pulmonary vein atresia |
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ACQUIRED DISEASE |
|
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INTRALUMINAL ANOMALIES |
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Pulmonary thromboembolism |
|
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In situ pulmonary artery thrombosis |
|
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Pulmonary tumor embolism |
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Pulmonary tumor thrombotic microangiography |
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Septic pulmonary embolism |
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Foreign bodies pulmonary embolism |
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Pulmonary artery sarcoma |
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VESSEL WALL LESIONS |
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Takayasu arteritis |
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Behçet disease |
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Swyer James Macleod Syndrome |
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Arterial dissection |
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EXTRALUMINAL ANOMALIES |
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Fibrosis mediastinitis |
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Tumor |
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Aortic aneurysm |
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Complications of radiofrequency ablation of atrial fibrillation |
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