Answer for BIR CoW 18 May 2025
Mycotic aneurysm of Left descending pulmonary artery
Findings
Cavitating Consolidation noted in the left lower lobe with non- enhancing areas on contrast administration- features suggestive of necrotising pneumonia A saccular outpouching is noted arising from a branch of the left descending pulmonary artery, consistent with a mycotic aneurysm. No evidence of contrast extravasation is seen to suggest active bleeding.
Discussion
Pulmonary artery aneurysms (PAAs) and pulmonary artery pseudoaneurysms (PAPAs) are rare vascular lesions that involve localized dilation of a segment of the pulmonary artery. PAAs involve all three layers of the vessel wall, while PAPAs involve only the outer layers. PAPAs are associated with a high risk of rupture, and their main infectious causes include fungi, tuberculosis, bacterial pneumonia, septic emboli, and, more recently, COVID-19. Other causes of PAAs and PAPAs include vasculitis, pulmonary hypertension, lung neoplasms, and iatrogenic factors such as cardiopulmonary surgery, radiotherapy, and percutaneous procedures. The presentation of PAPAs may be asymptomatic or, often, characterized by massive hemoptysis, dyspnea, and coughing, which can quickly evolve into hypovolemic hemorrhagic shock if not treated promptly. Associated Findings: Cavitary lung lesion, often with thick or irregular walls. Tree-in-bud appearance, fibrotic bands, or volume loss due to prior TB. Absence of systemic arterial supply (differentiates from bronchial artery pseudoaneurysms). No Contrast Extravasation: Indicates no active bleeding at the time of scan. With Active Bleeding: Look for contrast extravasation into the cavity or adjacent airways, potentially causing hemoptysis. Interventional Radiology Management of pulmonary artery pseudoaneurysm: 1. Pulmonary Artery Embolization (PAE): First-line IR treatment, especially if there is active bleeding. Involves selective catheterization of the pulmonary artery branch supplying the aneurysm. Embolic agents used: Coils – for precise occlusion of the aneurysmal segment. N-butyl cyanoacrylate (NBCA) glue – for rapid and permanent embolization. Amplatzer vascular plugs – in larger or more proximal aneurysms. Gelfoam or particles – rarely used due to risk of non-target embolization. 2. Bronchial Artery Embolization (BAE): Not directly used for Rasmussen aneurysm (which is pulmonary in origin). However, used as adjunct if bleeding source is also from hypertrophied bronchial arteries or in mixed vascular supply scenarios. 3. Stent-Graft Placement: Rarely used due to small caliber of peripheral pulmonary arteries. May be considered if aneurysm is more proximal or if coil embolization is not feasible. CT-guided Percutaneous Injection: Experimental or salvage option. Direct injection of glue or thrombin into the aneurysm under CT guidance, particularly in patients unfit for angiography. Goals of IR Management: Control life-threatening hemoptysis. Prevent aneurysm rupture. Preserve pulmonary parenchyma where possible.
Findings
Cavitating Consolidation noted in the left lower lobe with non- enhancing areas on contrast administration- features suggestive of necrotising pneumonia A saccular outpouching is noted arising from a branch of the left descending pulmonary artery, consistent with a mycotic aneurysm. No evidence of contrast extravasation is seen to suggest active bleeding.
Discussion
Pulmonary artery aneurysms (PAAs) and pulmonary artery pseudoaneurysms (PAPAs) are rare vascular lesions that involve localized dilation of a segment of the pulmonary artery. PAAs involve all three layers of the vessel wall, while PAPAs involve only the outer layers. PAPAs are associated with a high risk of rupture, and their main infectious causes include fungi, tuberculosis, bacterial pneumonia, septic emboli, and, more recently, COVID-19. Other causes of PAAs and PAPAs include vasculitis, pulmonary hypertension, lung neoplasms, and iatrogenic factors such as cardiopulmonary surgery, radiotherapy, and percutaneous procedures. The presentation of PAPAs may be asymptomatic or, often, characterized by massive hemoptysis, dyspnea, and coughing, which can quickly evolve into hypovolemic hemorrhagic shock if not treated promptly. Associated Findings: Cavitary lung lesion, often with thick or irregular walls. Tree-in-bud appearance, fibrotic bands, or volume loss due to prior TB. Absence of systemic arterial supply (differentiates from bronchial artery pseudoaneurysms). No Contrast Extravasation: Indicates no active bleeding at the time of scan. With Active Bleeding: Look for contrast extravasation into the cavity or adjacent airways, potentially causing hemoptysis. Interventional Radiology Management of pulmonary artery pseudoaneurysm: 1. Pulmonary Artery Embolization (PAE): First-line IR treatment, especially if there is active bleeding. Involves selective catheterization of the pulmonary artery branch supplying the aneurysm. Embolic agents used: Coils – for precise occlusion of the aneurysmal segment. N-butyl cyanoacrylate (NBCA) glue – for rapid and permanent embolization. Amplatzer vascular plugs – in larger or more proximal aneurysms. Gelfoam or particles – rarely used due to risk of non-target embolization. 2. Bronchial Artery Embolization (BAE): Not directly used for Rasmussen aneurysm (which is pulmonary in origin). However, used as adjunct if bleeding source is also from hypertrophied bronchial arteries or in mixed vascular supply scenarios. 3. Stent-Graft Placement: Rarely used due to small caliber of peripheral pulmonary arteries. May be considered if aneurysm is more proximal or if coil embolization is not feasible. CT-guided Percutaneous Injection: Experimental or salvage option. Direct injection of glue or thrombin into the aneurysm under CT guidance, particularly in patients unfit for angiography. Goals of IR Management: Control life-threatening hemoptysis. Prevent aneurysm rupture. Preserve pulmonary parenchyma where possible.
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
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Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!