CARDIOVASCULAR Flashcards

Question

Annuloaortic ectasia | 3

Answer 1

1. Marfan syndrome*—classically linked to this aneurysm type. 2. Other genetic disorders—e.g. Ehlers-Danlos syndrome, Loeys-Dietz syndrome, homocystinuria, osteogenesis imperfecta, Shprintzen-Goldberg syndrome. 3. Bicuspid aortic valve—aneurysm formation can occur regardless of aortic stenosis.

Answer 2

1. Poststenotic dilatation from aortic stenosis. 2. Previous aortic dissection—fusiform aneurysm + chronic dissection flap. 3. Atherosclerosis/hypertension—descending > arch > ascending aorta. Usually in older patients, fusiform morphology in most cases, but can be saccular.Cardiovascular system 127 6 4. Aortitis—e.g. Takayasu arteritis, giant cell arteritis, rheumatoid arthritis, seronegative spondyloarthropathies, relapsing polychondritis, SLE, Behçet’s disease, Cogan syndrome. 5. Congenital heart disease—as well as PDA and aortic coarctation. 6. Mycotic pseudoaneurysm—usually due to Staphylococcus aureus or Salmonella spp. Irregular, lobulated, noncalcified saccular aneurysm + adjacent fat stranding/abscess, can occur at any site but descending > ascending aorta. Rapidly progressive, high risk of rupture. In TB, pseudoaneurysms are usually due to extrinsic erosion of the aorta from an adjacent involved lymph node. HIV is also associated with aortitis and fusiform aneurysms. 7. Tertiary syphilis*—rare, usually causes saccular aneurysms of the ascending aorta. Associated with extensive confluent ‘tree-bark’ calcification of the aortic wall

Answer 3

1. Atherosclerosis/hypertension—often together with an AAA. 2. Previous aortic dissection or penetrating ulcer—postdissection aneurysms are usually fusiform, whereas penetrating ulcers progress to saccular aneurysms. 3. Previous trauma with missed rupture—focal saccular pseudoaneurysm at the anterior margin of the isthmus. Look for other signs of old trauma, e.g. healed rib fractures. 4. Mycotic pseudoaneurysm—see above. More common in descending aorta, including TB. 5. Kommerell diverticulum—saccular bulge at the origin of an aberrant subclavian artery.

Answer 4

. Intramural haematoma—characteristic crescentic hyperattenuation within the wall on unenhanced CT, which does not fill with contrast. 2. Vasculitis—particularly Takayasu arteritis (<50 years) and giant cell arteritis (>50 years). Circumferential wall thickening ± mild periaortic stranding. Can involve both thoracic and abdominal aorta ± major branches. Increased uptake on PET. Takayasu arteritis typically causes stenoses/occlusions. Other vasculitides (see Section 6.14) can also occasionally cause aortitis, but are usually limited to the ascending aorta. 3. IgG4-related disease*—can manifest as periaortitis, inflammatory AAA or RPF (ill-defined periaortic soft-tissue thickening ± IVC involvement/narrowing ± ureteric tethering/obstruction). Typically 128 Aids to Radiological Differential Diagnosis does not extend posterior to the aorta (cf. malignancy and Erdheim-Chester disease). Treated lymphoma can mimic RPF. 4. Infectious aortitis—usually associated with mycotic pseudoaneurysm, periaortic fat stranding ± abscess. Infection may be related to an indwelling stent/graft or could have spread from an adjacent source, e.g. discitis. 5. Erdheim-Chester disease*—ill-defined periaortic soft-tissue thickening sparing IVC and not displacing ureters. If perirenal soft-tissue thickening is also present this is almost pathognomonic

Answer 5

. Atherosclerosis—lumen narrowed by calcified and/or noncalcified plaque. In severe cases can lead to occlusion of the infrarenal aorta (aortoiliac occlusive disease). 2. Coarctation—in adults, usually just distal to the aortic isthmus + multiple collaterals. May be visible on CXR as a ‘figure 3’ aortic knuckle with inferior rib notching. Beware of pseudocoarctation, which is kinking of the aorta at the isthmus without true stenosis or collateral formation. 3. Takayasu arteritis—typically causes multifocal arterial stenoses. In the aorta the arch is the commonest site of stenosis. Aortitis and aneurysms may also be present. 4. Narrowing due to mass lesion or retroperitoneal fibrosis. 5. Midaortic syndrome—young patients, relatively long smooth narrowing of the suprarenal abdominal aorta ± involvement of renal arteries, SMA or coeliac axis ± multiple collaterals. Associated with NF1, Williams syndrome and Alagille syndrome. 6. Supravalvular aortic stenosis—focal smooth stenosis of the ascending aorta just distal to the sinuses of Valsalva, characteristic of Williams syndrome

Answer 6

1. Vasculitis (a) Kawasaki disease—characteristically produces coronary artery aneurysms ± stenoses. (b) Behçet’s disease*/Hughes-Stovin syndrome—both cause pulmonary artery aneurysms. (c) Takayasu arteritis—more commonly causes multifocal stenoses, but aneurysms of the arch vessels can also occur. (d) Polyarteritis nodosa*—classically causes multiple microaneurysms of the renal, hepatic and/or mesenteric arteries ± occlusions/infarcts. Best seen on angiography, may be occult on CT. A similar appearance may also be seen in SLE, Wegener’s granulomatosis and IV drug abuse-related necrotizing vasculitis. 2. Connective tissue disorders—Marfan syndrome, Ehlers-Danlos syndrome type 4 and Loeys-Dietz syndrome can all cause arterial aneurysms at any location, although the ascending aorta is most commonly involved. Loeys-Dietz syndrome classically also causes marked arterial tortuosity. 3. Fibromuscular dysplasia/segmental arterial mediolysis—both conditions are noninflammatory, nonatherosclerotic arteriopathies causing a characteristic ‘string of beads’ appearance in involved arteries due to alternating aneurysms and stenoses. FMD usually occurs in adults <50 years and most commonly involves the renal and carotid arteries. SAM usually occurs in adults >50 years and most commonly involves the mesenteric arteries, coeliac axis and branches. Dissection and haemorrhage is more common in SAM. 4. Neurofibromatosis*—can rarely cause arterial stenoses and aneurysms involving the aorta, arch vessels, renal arteries, intracranial arteries and visceral arteries

Answer 7

1. Atheroma—in arteries only, may be noncalcified or calcified. Noncalcified atheroma is irregular in shape and of low attenuation on CT. Aortic occlusion/stenosis caused by a large endoluminal calcification is known as a ‘coral reef aorta’. 2. Thrombus/embolus—thrombus is much more common in veins (e.g. DVT or superficial thrombophlebitis), but can occur in abnormal arteries, e.g. at sites of atherosclerosis or intimal damage (e.g. aortic injury), in aneurysms (crescentic mural thrombus) and in vasculitis. Emboli are found almost exclusively in arteries (and occasionally in hepatic portal veins), usually lodging at branching points ± signs of end-organ ischaemia. Acute thrombus is often hyperattenuating on unenhanced CT. MRI signal varies widely: acute thrombus (<7 days) is usually T1 isointense and T2 hypointense, subacute thrombus (7–14 days) is usually T1 and T2 hyperintense and chronic thrombus is usually T1 isointense and T2 hyperintense. Acute and subacute thrombus often shows high signal on DWI and low signal on T2*. Thrombus does not enhance on CT/MRI and does not show internal flow on Doppler US—any enhancement or internal vascularity suggests tumour thrombus. 3. Tumour thrombus—direct intravenous extension of a tumour, most commonly from RCC or HCC, but can also be seen with adrenal carcinoma, pancreatic NET and leiomyosarcoma. Tumour thrombus usually shows internal flow on Doppler US, enhances on CT/MRI and often expands the vein. Rarely, intravenous extension can occur from uterine fibroids (intravenous leiomyomatosis)—this usually involves the pelvic veins and IVC, but can extend into the right heart. 4. Nonthrombotic pulmonary emboli. 5. Cystic adventitial disease—rare, typically presents in young adult males as a benign multiloculated cystic mass arising from the adventitia of the popliteal artery causing luminal narrowing. Can occasionally involve other arteries (and rarely veins) adjacent to joints. 6. Intravascular lipoma—rare. Most commonly arises from the IVC; characteristic fatty appearance on CT/MRI. 7. Intravenous lobular capillary haemangioma—rare. Most commonly arises from veins in the neck/arms. Hypervascular on Doppler US, enhances on CT/MRI. 8. Primary vascular sarcomas—rare. Typically involve large veins or, less commonly, large arteries. Usually demonstrate internal flow on Doppler US and enhancement on CT/MRI ± extravascular invasion. Pulmonary artery sarcomas may mimic pulmonary emboli. Arterial sarcomas may mimic focal atheroma, particularly on CT where internal enhancement may be difficult to appreciate. Venous sarcomas often cause vessel expansion and associated thrombosis. Leiomyosarcoma is the most common subtype (most arising from the IVC); other subtypes include intimal sarcoma (most arising from the descending aorta or central pulmonary arteries), angiosarcoma, synovial sarcoma and epithelioid haemangioendothelioma

Answer 8

1. Type I—from the graft attachment site. Type Ia proximal. Type Ib distal. Contrast present in sac, usually on arterial phase. High pressure, high risk; requires treatment. 2. Type II—retrograde sac filling from collateral vessels (inferior mesenteric and lumbar arteries). Most common type; best depicted on delayed phase. 50% spontaneously resolve. Serial surveillance and treatment if sac expands. 3. Type III—structural failure of stent graft, including junctional separations, fractures or perforations of the graft. High pressure, high risk; requires treatment. 4. Type IV—sac filling through graft fabric due to graft porosity after placement. By definition not detected on follow-up imaging. 5. Type V—endotension; sac expansion without visible endoleak. Controversial, usually occult Type I–IV endoleak or ultrafiltration of blood.

Answer 9

1. Pulmonary hypertension—dilated MPA and bilateral central PAs with peripheral pruning. See Section 6.21. 2. Left-to-right shunt—dilated MPA, central and peripheral PAs (plethora). 3. Pulmonary valve stenosis—dilated MPA only (± left PA). 4. Marfan syndrome*—can rarely cause MPA root dilatation.

Answer 10

1. Vasculitis—typically in Behçet’s disease, but consider Hughes-Stovin syndrome if there are no oral/genital ulcers. Often multiple ± thrombosis ± pulmonary infarcts. High risk of rupture. 2. Chronic pulmonary hypertension—particularly in left-to-right shunts, e.g. PDA, due to shear stresses. Associated mural thrombus/calcification is common. Aneurysms may be very large. 3. Mycotic pseudoaneurysm—e.g. due to lung abscess, septic emboli, TB (Rasmussen aneurysm), invasive fungal infection or tertiary syphilis. 4. Traumatic pseudoaneurysm—most commonly due to Swan-Ganz catheters. 5. Malignancy—a lung tumour/metastasis may erode into an adjacent pulmonary artery, causing a pseudoaneurysm. Primary sarcoma of the pulmonary artery can also cause focal aneurysmal dilatation with an intraluminal mass ± extraluminal extension. 6. AVM—look for dilated feeding pulmonary artery and draining vein

Answer 11

Pulmonary venous hypertension—due to left heart failure (e.g. LVF, mitral valve disease). Pulmonary oedema and pleural effusions may be present. 2. Chronic lung disease—e.g. emphysema, interstitial lung disease, cystic fibrosis, LCH, LAM, hypoventilation. 3. Chronic thromboembolic pulmonary hypertension (CTEPH)— signs on CT include laminar thrombus (usually seen in larger arteries), intraluminal webs, pulmonary artery stenoses/occlusions (may be very subtle in smaller vessels—look for bronchi without accompanying arteries), peripheral lung scarring due to previous infarcts, dilated bronchial arteries (due to collateralization) and mosaic attenuation in the lungs with smaller pulmonary arteries in the more lucent areas. 4. Chronic left-to-right shunt—e.g. ASD, VSD, PDA, partial anomalous pulmonary venous return (PAPVR). 5. Vasculitis—Takayasu arteritis often involves the pulmonary arteries, causing multifocal stenoses/occlusions, which can mimic CTEPH. Behçet’s disease and Hughes-Stovin syndrome can also cause Cardiovascular system 133 6 pulmonary artery stenoses/occlusions due to thrombosis/emboli in addition to the characteristic PA aneurysms. Small vessel vasculitides can also cause pulmonary hypertension ± areas of pulmonary haemorrhage ± nodules/cavities, but the pulmonary arteries visible on CT typically appear normal. 6. Pulmonary venoocclusive disease—usually young adults. HRCT features are similar to LVF with interlobular septal thickening, pleural effusions and ground-glass opacities, but with a normal left heart. Centrilobular nodules are usually absent (cf. below). 7. Pulmonary capillary haemangiomatosis—usually young adults. Widespread ill-defined centrilobular nodules on HRCT. Interlobular septal thickening is rare. Normal left heart. 8. Idiopathic pulmonary arterial hypertension—typically young adult women. Usually no other imaging features apart from those of pulmonary hypertension. 9. Other causes—sarcoidosis, connective tissue diseases (e.g. scleroderma), fibrosing mediastinitis, portal hypertension, NF1, HIV, schistosomiasis, drugs/toxins and others.

CARDIOVASCULAR Flashcards

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