Imaging Pearls ❯ Cardiac ❯ Pulmonary Artery and Veins
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- “Pulmonary artery (PA) aneurysms are rare vascular abnormalities with potentially life-threatening complications such as rupture, massive hemoptysis, and pulmonary infarction. These conditions are often asymptomatic and incidentally detected but can present with nonspecific symptoms like cough, dyspnea, or hemoptysis in an emergency setting. Multidetector CT pulmonary angiography (CTPA) has outshone traditional angiography, supplemented by advanced 3D post-processing techniques such as maximum intensity projection (MIP), volumetric rendering (VR), and cinematic rendering (CR) techniques, playing a pivotal role in diagnosis and management of PA aneurysms.”
CT imaging of pulmonary artery aneurysms in the emergency department - What you need to know.
Yasrab M, Crawford CK, Fishman EK, Kawamoto S.
Curr Probl Diagn Radiol. 2025 May 17:S0363-0188(25)00094-5. - “Pulmonary artery (PA) aneurysms are rare vascular abnormalities involving the PA or its branches, with an incidence of 0.007 % according to classical autopsy series. In an emergency setting, they can pose a risk of rupture and massive hemoptysis, which itself has a mortality rate of over 50 % if untreated. Ten percent of massive hemoptysis is due to PA pathology, most commonly aneurysms and pseudoaneurysms. True PA aneurysms are dilatations involving all three layers of the vessel, whereas pseudoaneurysms are outpouchings contained by the innermost layer, with a comparatively higher risk of rupture. Other complications include thrombosis and dissections, which can lead to pulmonary infarction.”
CT imaging of pulmonary artery aneurysms in the emergency department - What you need to know.
Yasrab M, Crawford CK, Fishman EK, Kawamoto S.
Curr Probl Diagn Radiol. 2025 May 17:S0363-0188(25)00094-5. - “PA aneurysms can be idiopathic or develop in association with various underlying etiologies, including congenital cardiovascular anomalies, infections, neoplastic processes, trauma, connective tissue disorders, and systemic inflammatory conditions. Iatrogenic injury during catheterization can also predispose to aneurysm and pseudoaneurysm formation, with the latter more frequently a consequence of trauma or infection. Patients are often asymptomatic with aneurysms being discovered incidentally during imaging for other reasons; however, when symptomatic, patients can present with nonspecific complaints including cough, dyspnea, and/or hemoptysis, as well as palpitations or syncope. Additional symptoms can provide further diagnostic clues depending on the underlying cause.”
CT imaging of pulmonary artery aneurysms in the emergency department - What you need to know.
Yasrab M, Crawford CK, Fishman EK, Kawamoto S.
Curr Probl Diagn Radiol. 2025 May 17:S0363-0188(25)00094-5. - Causes of PA Aneurysms and Pseudoaneurysms
- “At our institution, CTPA is currently performed on 64- or 128-detector multidetector CT (MDCT) scanners (Somatom Definition Force or Siemens Definition Flash, Siemens Healthcare, Erlangen, Germany). Scans are performed in a craniocaudal direction from the lung apices to the diaphragm. 100 ml of intravenous (IV) non-ionic contrast (Omnipaque 350 mg I/ml, GE Healthcare) is injected peripherally at a rate of 4- 5 ml/second. 200 HU or 250 HU trigger threshold is set for bolus tracking at the pulmonary trunk as the region of interest. Tube potential is set at 100-120 kV, tube current at 120-200 mA (automatically modulated with CareDose, Siemens), and collimation of 128 × 0.6 mm. Scan time is usually under 10 seconds and can be even shorter when using high pitch scanners.”
CT imaging of pulmonary artery aneurysms in the emergency department - What you need to know.
Yasrab M, Crawford CK, Fishman EK, Kawamoto S.
Curr Probl Diagn Radiol. 2025 May 17:S0363-0188(25)00094-5. - “Involvement of more peripheral branches and multiple sites of aneurysm formation should raise concern for systemic pathologies including connective tissue disease and vasculitis. This is especially true in younger patients who present with PA aneurysms and may even show involvement of the aorta and its branches, for instance in Marfan’s syndrome.8 Behcet’s disease is a systemic vasculitis predominantly common in Middle Eastern, Asian, and particularly Turkish populations, is another important cause for PA aneurysms. Obliterative endarteritis of the vasa vasorum (in Behcet’s disease) results in aneurysm formation, which can have variable sizes and locations involving the segmental and even subsegmental PA branches and associated thrombosis in up to a third of these cases."
CT imaging of pulmonary artery aneurysms in the emergency department - What you need to know.
Yasrab M, Crawford CK, Fishman EK, Kawamoto S.
Curr Probl Diagn Radiol. 2025 May 17:S0363-0188(25)00094-5. - Pseudoaneurysms secondary to trauma or iatrogenic injury (including right heart or Swan-Ganz catheterization) are often associated with pulmonary hemorrhage with active extravasation, and consolidation or ground-glass opacities appreciated on lung windows. Multiple pseudoaneurysms can also develop in association with endocarditis, septic emboli, or lung metastases, in which cases there is a higher predilection for involvement of subsegmental branches. Infection remains the most common etiology for pseudoaneurysms (i.e. mycotic aneurysms) as granulation tissue erodes the vessel wall, although we see lower rates of the classically described Rasmusen aneurysm (secondary to tuberculosis) due to decreasing infection rates in developed countries. Nonetheless, signs and symptoms of infection with possible cavitary lesions with enhancing walls and consolidation in association with the aneurysm should prompt further workup.
CT imaging of pulmonary artery aneurysms in the emergency department - What you need to know.
Yasrab M, Crawford CK, Fishman EK, Kawamoto S.
Curr Probl Diagn Radiol. 2025 May 17:S0363-0188(25)00094-5. - Diagnosing PA aneurysms in the emergency department can be challenging due to their nonspecific symptoms like cough, dyspnea, and hemoptysis, which overlap with various pulmonary and cardiovascular diseases. Achieving optimal image quality is essential; issues such as patient movement, improper contrast timing, and technical limitations can significantly affect the resolution of standard axial images, and therefore the effectiveness of advanced postprocessing techniques like MIP, VR, and 3D CR, all of which rely on high quality standard 2D acquisitions. Additionally, precise timing of contrast administration and image acquisition is critical for adequate enhancement of the pulmonary vessels without obscuring aneurysmal features, which is particularly challenging in unstable patients where it may not be clear where the bleeding is originating from. Even in the case of hemorrhage, a CTPA is recommended to determine whether the source of the bleeding is from the pulmonary vessels or the bronchial arteries.
CT imaging of pulmonary artery aneurysms in the emergency department - What you need to know.
Yasrab M, Crawford CK, Fishman EK, Kawamoto S.
Curr Probl Diagn Radiol. 2025 May 17:S0363-0188(25)00094-5. - “Management of PA aneurysms often hinges on multiple factors, including the aneurysm’s size and location, and the patient’s stability, with a notable absence of consensus guidelines for intervention thresholds. The wide array of potential etiologies, from congenital defects to acquired diseases like connective tissue disorders or infections, demands a broad differential diagnosis that influences treatment choices based on the individual pathology and the patient’s condition after initial stabilization.”
CT imaging of pulmonary artery aneurysms in the emergency department - What you need to know.
Yasrab M, Crawford CK, Fishman EK, Kawamoto S.
Curr Probl Diagn Radiol. 2025 May 17:S0363-0188(25)00094-5. - “In summary, PA aneurysms and pseudoaneurysms are rare but critical findings in the emergency setting. CTPA, supported by advanced techniques, serves as an efficient imaging modality of choice for accurate diagnosis and effective procedural planning. The wide spectrum of underlying causes and potential complications highlights the importance of a personalized approach to management, balancing patient stability and risk of rupture. Through these illustrative cases, we aim to emphasize the indispensable role of radiological imaging in identifying and addressing these high-risk vascular abnormalities in an emergency setting.”
CT imaging of pulmonary artery aneurysms in the emergency department - What you need to know.
Yasrab M, Crawford CK, Fishman EK, Kawamoto S.
Curr Probl Diagn Radiol. 2025 May 17:S0363-0188(25)00094-5.
- “ This study shows that missed PE can occur on abdominal CT. It is recommended that interpretation include a careful search of the lower pulmonary arterial vasculature on contrast-enhanced abdominal CT scans.”
Missed Pulmonary Embolism on Abdominal CT
Lim KY, Kligerman SJ, Lin CT, White CS
AJR 2014; 202:738-743 - “ The challenge in identifying PE is clearly greater on abdominal CT than on chest CT. In addition to the multiple pitfalls described already, the lungs are typically not a primary target of abdominal CT interpretation, and only a limited part of the pulmonary anatomy is included.”
Missed Pulmonary Embolism on Abdominal CT
Lim KY, Kligerman SJ, Lin CT, White CS
AJR 2014; 202:738-743
- Congenital Causes of Right Heart Dilatation in Adults
- Pretricuspid left to right shunts
- Posttricuspid left to right shunts
- Tricuspid valve regurgitation
- Myocardium
- Pulmonary valve regurgitation - " Pulmonary vein diameter, cross sectional area and shape vary. Particular care must be taken when the left inferior pulmonary vein is evaluated for stenosis, as it normally narrows as it enters the left atrium."
Pulmonary Vein Diameter, Cross Sectional Area, and Shape: CT Analysis
Kim YH et al
Radiology 2005; 235:43-50 - " Caliber of the left inferior pulmonary vein decreased as it entered the left atrium. None of the veins were round; all were ovoid. Left sided veins and venous ostia were less round than right sided veins."
Pulmonary Vein Diameter, Cross Sectional Area, and Shape: CT Analysis
Kim YH et al
Radiology 2005; 235:43-50