Artifacts in Contrast-Enhanced Ultrasound during Follow-up after Endovascular Aortic Repair: Impact on Endoleak Detection in Comparison with Computed Tomography Angiography

Ultrasound Coded-Excitation Imaging for Endoleak Detection After Complex Endovascular Aortic Repair

OBJECTIVES

Several imaging modalities have been suggested for surveillance after fenestrated endovascular aortic repair in general and endoleak detection in specific. In the present project a coded excitation-based ultrasound (B-Flow) was investigated for endoleak detection after complex endovascular aortic repair.

METHODS

Patients post complex endovascular aortic repair (FEVAR or T/FEVAR) undergoing follow-up appointments including ultrasonography of the aorta at a vascular and endovascular surgery outpatient center were included in the study. B-Flow was compared with computed tomography angiography (CTA), Duplex ultrasound (DUS), and contrast-enhanced ultrasound (CEUS) regarding agreement and reliability for endoleak detection and characterization.

RESULTS

In total, 47 follow-ups were included. They accumulated in a total of 149 imaging investigations. Endoleaks were discovered in 44.7% of B-Flow studies and a majority of these endoleaks were classified as type II. Agreement between B-Flow and other imaging modalities was good (>80.0%) in general. However, with B-Flow 6 and 2 endoleaks would have been missed compared with CEUS and CTA, respectively. Regarding endoleak classification, B-Flow had a strong agreement (94.5%) with CEUS in detected cases. Furthermore, in a limited subset analysis, imaging findings were externally validated using findings from angiography.

CONCLUSIONS

Ultrasonography allows for endoleak detection and characterization without an invasive procedure or the use of potentially nephrotoxic contrast medium and can reduce radiation exposure. While CEUS mitigates issues of radiation and nephrotoxicity it still requires the intravenous application of contrast enhancers. Ultrasound coded-excitation imaging such as B-Flow could therefore further simplify endoleak surveillance after fenestrated endovascular aortic repair.

Pseudoendoleak: A post‐endovascular aortic repair ultrasound surveillance pitfall – Single institution case series

INTRODUCTION

In the context of increasingly common endovascular treatment for abdominal aortic aneurysms, endoleak is a relatively common complication of (abdominal) EVAR, and ongoing multimodality surveillance programs are recommended by expert bodies including the Society for Vascular Surgery (SVS). We describe the colour doppler ultrasound (CDUS) finding defined as pseudoendoleak that may be misinterpreted as significant endoleak and may be resolved through the use of contrast-enhanced ultrasound (CEUS).

METHODS

Retrospective review of cases at our institution identified five cases where apparent endoleak on CDUS was not evident on CEUS, performed immediately following CDUS.

RESULTS

Each of these five cases demonstrated interval increase in sac size at varying intervals post-EVAR, and in 4 out of 5 cases, no endoleak was demonstrated on multiple other modalities, at multiple time points. One case demonstrated an isolated type 2 endoleak at one time point, a finding that could not be reproduced. In each case, index-positive CDUS is thought to represent agitated fluid within the excluded sac that is not in continuity with the arterial blood pool as evidenced by the absence of CEUS enhancement.

CONCLUSIONS

In cases of positive post-EVAR CDUS, CEUS is an effective tool to exclude the presence of pseudoendoleak and thus avoid further and potentially invasive diagnostic modalities in an elderly and comorbid cohort.