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False aneurysm

Last revised by Dr Ammar Ashraf on 19 Nov 2021

False aneurysms, also known as pseudoaneurysms, are abnormal outpouchings or dilatation of arteries which are bounded only by the tunica adventitia, the outermost layer of the arterial wall. These are distinguished from true aneurysms, which are bounded by all three layers of the arterial wall. Pseudoaneurysms typically occur when there is a breach in the vessel wall such that blood leaks through the inner wall but is contained by the adventitia or surrounding perivascular soft tissue.

They can involve any arterial segment or even a cardiac chamber. Examples include

Some of the imaging features may be dependent on location.

Due to the turbulent forward and backward flow, a characteristic yin-yang sign may be seen on color flow while a "to and fro" pattern may be seen with pulsed Doppler.

  • hypoattenuating (non-contrast) or hyperattenuating (contrast-enhanced) smooth-walled sac adjacent to an artery, usually with a communication 6

The risk of rupture is higher than that of a true aneurysm of comparable size due to poor support of the aneurysm wall and thus false aneurysms generally require treatment.

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Cases and figures

  • Figure 1
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  • Figure 2: types of aneurysms
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  • Case 1: gastroduodenal artery pseudoaneurysm
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  • Case 2: right femoral
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  • Case 3: common carotid pseudoaneurysm
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  • Case 4: radial artery
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  • Case 5: carotid artery pseudoaneurysm
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  • Case 6: left ventricular pseudo-aneurysm
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  • Case 7
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  • Case 8
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  • Case 9
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  • Case 10: hepatic artery pseudoaneurysm
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  • Case 11: carotid arterial pseudoaneurysm
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  • Case 12: aortic root pseudoaneurysm
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  • Case 13: brachiocephalic arterial pseudoaneurysm
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  • Case 14: post renal transplant
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  • Case 14: on ultrasound (video)
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  • Case 15: traumatic - small
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  • Case 16: renal arterial pseudonaeurysm
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  • Case 17: gastroduodenal artery pseudo-aneurysm
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  • Case 18: radial artery pseudoaneurysm
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  • Case 19: iatrogenic internal mammary artery pseudoaneurysm
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  • Case 20: anterior tibial artery false aneurysm
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  • Case 21: subclavian artery
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  • Case 22: popliteal artery pseudoaneurysm
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