Learning objectives
Review the various imaging modalities related to endoleak detection & surveillance
Evaluate the sensitivity and specificity of computed tomography,
contrast-enhanced ultrasound,
nuclear medicine and magnetic resonance angiography in the evaluation of endoleaks.
Consider the advantages and disadvantages of each modality in the assessment of endoleaks
Background
Endoleaks represent persistent flow of blood into the aneurysm sac following endovascular aneurysm repair (EVAR) either from adefect in the stent or related to afeeding vessel potentially nullifying the principles of aneurysm repair and rupture prevention.
The detection and surveillance of endoleaks requires lifelong imaging with computed tomography (CT) beingthe current the modality of choice.
However,
other modalities are becoming increasingly refined and can also be used as adjuncts.
In particular,
two & three-dimensional contrast enhanced ultrasound has been evaluated.
Red cell scinitigraphy,
magnetic resonance...
Findings and procedure details
Computed tomography (CT) demonstrates a consistently high sensitivity and specificity for the detection of endoleaks[1].
This modality presents excellent spatial resolution and reproducibility with scans performed in a matter of seconds[2].
However,
lifelong surveillance with CT will lead to a significant radiation burden and the risks of contrast-induced nephrotoxicity in patients with renal dysfunction are wellrecognised[3].
Magnetic resonance angiography (MRA) with gadolinium can approach the diagnostic capability of CT[4] butstents constructed from stainless steel can cause marked artefact leading to a non-diagnostic study.
In addition,...
Conclusion
Endoleaks are a common complication of EVARs and require lifelong surveillance.
Multiple imaging modalities can be used for assessment with contrast-enhanced ultrasound becoming an increasingly useful option particularly in the context of renal dysfunction and concern about radiation exposure.
References
[1] Stavropoulos S,
Charagundla S.
Imaging Techniques for Detection and Management of Endoleaks after Endovascular Aortic Aneurysm Repair 1.
Radiology.
2007;243(3):641-655.
[2] Shah A,
Stavropoulos S.
Imaging Surveillance following Endovascular Aneurysm Repair.
Semin intervent Radiol.
2009;26(01):010-016.
[3] Stolzmann P,
Frauenfelder T,
Pfammatter T,
et al.
Endoleaks after endovascular abdominal aortic aneurysm repair: detection with dual-energy dual-source CT.Radiology.2008;249:682–691.
[4] WeigelS,
Tombach B,
Maintz D,
et al.
Thoracic aortic stent graft: comparison of contrast-enhanced MR angiography and CT angiography in the follow-up—initial results.Eur Radiol2003;13:1628–1634
[5] Stavropoulos S...