December 2023
Authors:
Dr Ken-win To, Radiology fellow, Guys and St Thomas Hospital
History:
CTPA – likely occluded left pulmonary artery with collateral circulation
Images:
Figure 1: CT Pulmonary Angiogram in axial plane demonstrating non opacification of the left pulmonary artery.
Figure 2: CT Pulmonary Angiogram in axial plane demonstrating non opacification of the left pulmonary artery. Collateralisation of vessels around the left pulmonary artery. Also circumferential thickening of the ascending aorta, worse posteriorly.
Figure 3: CT Pulmonary Angiogram in axial plane demonstrating non opacification of the left pulmonary vein and reduced enhancement of the left lung pulmonary vasculature.
Figure 4: CT Pulmonary Angiogram in coronal plane demonstrating non opacification of the left pulmonary artery. Collateralisation of vessels around the left pulmonary artery. Also circumferential thickening of the ascending aorta, and reduced enhancement of the left lung pulmonary vasculature
Diagnosis – Occluded left pulmonary artery secondary to Takayasu arteritis
Takayasu’s arteritis, also known as “pulseless disease”, is a large vessel vasculitis that typically involves the aorta and its major branches. There is a predominance in female patients and Asian patients, often under 50 years of age, with symptoms occurring in the second or third decades of life. There is a possible link between TA and M.tuberculosis.
Clinical symptoms can be vague such as fatigue, anorexia and musculoskeletal complains. This often leads to ischaemic symptoms due to stenotic lesions or thrombus formation, which may involve the brain, heart, limbs, abdomen and lungs. These can include shortness of breath and chest pain.
The pathology is segmental and patchy granulomatous inflammation of the aorta which results in stenosis, thrombosis and aneurysm formation. This progresses to inflammatory and obliterative changes in the aorta and its branches. Peripheral pulses are often reduced or absent, giving the term ‘pulseless disease’. Cardiac complications can occur in up to 60% of cases. Pulmonary arterial involvement is also common.
Takayasu arteritis is classified based on location of involvement. Starting solely involving the aortic arch and branches (type I), to involvement of both the thoracic, abdominal aorta and renal arteries (type III) and generalised involvement of all aortic segments (type V).
CT findings consist of wall thickening and/or enhancement in the active acute phase (see figures 2 and 4), aortic valve disease, occlusion of the major aortic branches, aneurysmal dilatation or pseudoaneurysm of the aorta or its branches, and late phase diffuse narrowing distally in the descending and abdominal aorta.
The pulmonary arteries are also commonly involved, with the most common appearance being peripheral pruning (see figures). Pulmonary hypertension can be present in 12% of patients. CT pulmonary angiogram (CTPA) can show focal oligaemia due to pulmonary artery stenosis and wall thickening, and can lead to pulmonary infarcts. Pulmonary artery aneurysms are rare, but there are cases of rupture.
CT coronary angiograms can also show stenosis of the coronary ostium and within the vessel, coronary artery aneurysms. A string of pearls sign is characterised by a combination of stenosis and aneurysms.
Treatment is often systemic steroids. Methotrexate, cyclophosphamide, and ciclosporin are alternative steroid sparing therapy. Intervention includes percutaneous angioplasty and bypass surgery. Prognosis is often variable.
Questions:
Which of the following are true about typical the sites of disease of Takayasu Arteritis?
Lower limb arteries (F)
Intra-cranial arteries (F)
Coronary arteries (T)
Renal arteries (T)
Pulmonary arteries (T)
Which of the following are true regarding typical presentation of Takayasu Arteritis?
Systemic non-specific illness (fever, night sweats, fatigue, anorexia, musculoskeletal aches) (T)
Male predominant (F)
Affects ages 60+ years of age (F)
Geographic concurrence of cases with Tuberculosis (T)
Shortness of breath and chest pain (F)
Which of the following are true regarding pulmonary findings of Takayasu Arteritis?
Pulmonary emboli (PE) are often seen on CTPA (F)
Pulmonary artery aneurysms are common (F)
It causes pulmonary artery stenosis and wall thickening (T)
Pulmonary hypertension is present in over 50% of cases (F)
It is associated with focal oligaemia (T)
References:
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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6165863/