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 well recognised[3].

Magnetic resonance angiography (MRA) with gadolinium can approach the diagnostic capability of CT[4] but stents constructed from stainless steel can cause marked artefact leading to a non-diagnostic study. In addition, the spatial resolution of MRA is inferior to and takes far longer to perform than a CT scan. Gadolinium is also linked to nephrogenic systemic fibrosis although obviously, MRA does not involve radiation.

Technetium sulfur colloid and red bood cells scans are rarely used in clinical practice and demonstrate reduced sensitivity and specificity when compared to CT angiography[5].

Radiography is a useful modality for the macroscopic assessment of stent placement and evidence of kinking but is otherwise limited.

Contrast-enhanced ultrasound has shown equivalent sensitivity & specificity, occasionally demonstrating endoleaks not apparent on CT[6]. This modality allows the intricate review of flow dynamics within the aneurysm scan in realtime with abiltiy to administer additional microbubbles if there are equivocal imaging characteristics. Three-dimensional contrast enhanced ultrasound has actually demonstrated superior diagnostic ability in some studies[7].

However, the disadvantages of ultrasound are self-evident and relate to operator experience and sac obscuration as a result of bowel gas & patient habitus. Furthermore, contrast-enhanced ultrasound can be time consuming.