Contrast-Enhanced Ultrasound vs. CT Angiography in Fenestrated EVAR Surveillance:A Single-Center Comparison

Abstract

To evaluate contrast-enhanced ultrasound (CEUS) as an effective alternative to computed tomographic angiography (CTA) during follow-up after fenestrated endovascular aneurysm repair (EVAR) of juxtarenal aortic aneurysms. Between January 2008 and April 2011, 62 patients (all men; mean age 72 years) underwent fenestrated EVAR follow-up with both CTA and CEUS. In a retrospective analysis, the first CTA and CEUS postoperative examinations after EVAR were compared for endoleak detection, aneurysm sac diameter, and target vessel patency. The examinations were performed within 30 days of the procedure and the interval between the 2 scans was <7 days. Only fenestrated endografts with up to 3 fenestrations (with or without a scallop) were eligible so that the entire implant could be visualized with standard abdominal ultrasound. The mean diameters of the aneurysm sac were 56.58±8.56 mm with CEUS and 57.70±8.59 mm with CTA. The mean difference in aneurysm sac diameter was -1.13±3.19 mm (95% CI -0.34 to -1.92), with CTA measurements tending to be slightly larger. Bland-Altman plots showed good agreement between the imaging modalities with respect to aneurysm sac diameter (Spearman correlation coefficient r(s)=0.921, p<0.01). Endoleaks were detected by CTA in 7 (11.3%) of 62 patients and by CEUS in 6 (9.7%). In 59 (95.16%) cases, the tests agreed, and their equivalence was confirmed by binomial distribution testing. There was complete agreement between CEUS and CTA in the assessment of target vessels (144/146 patent target arteries; 1 had a significant stenosis and another was thrombosed). CEUS is as accurate as CTA in endoleak detection, abdominal aortic aneurysm diameter measurement, and the evaluation of target vessels during surveillance of fenestrated stent-grafts. Although it cannot yet be proposed as the only imaging modality during follow-up, CEUS could be usefully employed with the self-evident advantage of reducing lifetime exposure to ionizing radiation.