Evaluation of abdominal aortic aneurysm after endovascular repair: prospective validation of contrast-enhanced US with a second-generation US contrast agent.

PURPOSE

To prospectively assess the accuracy of contrast agent-enhanced (CE) ultrasonography (US) with a second-generation US contrast agent in the detection and classification of endoleaks after endovascular repair of abdominal aortic aneurysms (EVAR), with computed tomographic (CT) angiography as the reference standard.

MATERIALS AND METHODS

Institutional review board and written informed consent were obtained. Thirty-five patients who underwent EVAR were enrolled in a prospective study that consisted of CT angiography and CE US studies performed at 1- and 6-month follow-up and performed yearly thereafter. CE US was performed after bolus injection of 2.4 mL of sulfur hexafluoride by using equipment with specific software for contrast studies. Angiography was performed in patients who had type II endoleaks with an increase in aneurysm sac size and in patients with type I or III endoleaks. CE US sensitivity, specificity, positive and negative predictive values, and accuracy were determined for endoleak detection, and Cohen κ statistic was used to assess agreement of CE US and CT angiographic findings for endoleak classification.

RESULTS

A total of 126 CT angiographic and CE US studies were performed. CT angiography depicted 34 endoleaks in 16 patients (type IA, n=1; type IB, n=1; type II inferior mesenteric artery, n=2; type II lumbar artery, n=28; type II complex, inferior mesenteric, and lumbar arteries, n=2). CE US depicted 33 endoleaks. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CE US in endoleak detection were 97%, 100%, 100%, 98%, and 99%, respectively. CE US enabled correct classification of 26 of 33 endoleaks. No clinically important endoleak was missed at CE US.

CONCLUSION

CE US yields good sensitivity, specificity, and accuracy in endoleak detection, and it might represent a noninvasive tool that can be used in the follow-up of patients who undergo EVAR.