Learning objectives
To list down the causes of pseudoaneurysms
To illustrate the imaging spectrum of pseudoaneurysms on Ultrasonography (US),
Computed tomography (CT) and catheter angiography
To describe the role of minimally invasive techniques for their treatment and to review the advantages and limitations of each of them
Background
Pseudoaneurysms,
also known as false aneurysms,
are formed when there is a breach in the inner layer of the vessel wall such that blood seeps through it but is contained by the tunica adventitia or the surrounding perivascular soft tissue.
The defect acts as a means of direct communication between the arterial blood flow and the sac of the aneurysm.1,2
Causes of pseudoaneurysms as are listed below1,2:
Trauma
Iatrogenic (e.g.
arterial catheterisation,
biopsy,
surgery)
Spontaneous dissection
Fibromuscular dysplasia
Regional inflammatory process
Vessel injury/erosion due to...
Findings and procedure details
US & Colour Doppler (Figures 1 and 2)
Imaging features:
Pseudoaneurysm appears as an irregular hypoechoic cystic structure on Gray-scale US located in relation to a supplying parent artery.
Ultrasound characterizes the pseudoaneurysm in terms of number,
size of the sac,
number of compartments within the sac and the size of the neck,
simple or complex nature and the presence of septae.
Differential diagnosis of pseudoaneurysms on gray scale US would include simple and complex cysts and hematomas.3
On Colour Doppler,
the 'yin-yang' sign is...
Conclusion
Low-frequency US transducers with gray-scale and color Doppler capabilities provide valuable anatomic and flow related information besides playing a significant therapeutic role by means of compression or guided thrombin injection.
CT offers the advantage of spatial resolution and possible etiological diagnosis.
Catheter angiography,
however is the gold standard for diagnosis and offers therapeutic options as well in the form of coiling and stent remodelling.
These non-invasive and minimally invasive endovascular procedures offer prompt treatment and reduce the need for surgical repair.
References
1.
Kumar V,
Abbas AK,
Fausto N.
Robbins and Cotran Pathologic Basis of Disease. W B Saunders Co.
(2005) ISBN:0721601871.
2.
Kaufman JA,
Lee MJ.
Vascular & Interventional Radiology.
Mosby Inc.
(2004) ISBN:0815143699
3.
Saad NE,
Saad WE,
Davies MG,
Waldman DL,
Fultz PJ,
Rubens DJ.
Pseudoaneurysms and the Role of Minimally Invasive Techniques in Their Management. Radiographics.
2005; 25: S173–S189.
4.
Mansour MA,
Gorsuch JM: Diagnosis and Management of Pseudoaneurysms. Perspect Vasc Surg Endovasc Ther.
2007,
19:58–64.
5.
Lupattelli T.
The Yin-yang Sign. Radiology....