Contemporary Applications of Ultrasound in Abdominal Aortic Aneurysm Management

Abstract

Ultrasound (US) is a well-established screening tool for detection of abdominal aortic aneurysms (AAAs) and is currently recommended not only for those with a relevant family history but also for all men and high-risk women older than 65 years of age. The advent of minimally invasive endovascular techniques in the treatment of AAAs [endovascular aneurysm repair (EVAR)] has increased the need for repeat imaging, especially in the postoperative period. Nevertheless, preoperative planning, intraoperative execution, and postoperative surveillance all mandate accurate imaging. While computed tomographic angiography and angiography have dominated the field, repeatedly exposing patients to the deleterious effects of cumulative radiation and intravenous nephrotoxic contrast, US technology has significantly evolved over the past decade. In addition to standard color duplex US, 2D, 3D, or 4D contrast-enhanced US modalities are revolutionizing AAA management and postoperative surveillance. This technology can accurately measure AAA diameter and volume, and most importantly, it can detect endoleaks post-EVAR with high sensitivity and specificity. 4D contrast-enhanced US can even provide hemodynamic information about the branch vessels following fenestrated EVARs. The need for experienced US operators and accredited vascular labs is mandatory to guarantee the reliability of the results. This review article presents a comprehensive overview of the literature on the state-of-art US imaging in AAA management, including post-EVAR follow-up, techniques, and diagnostic accuracy.

Keywords: EVAR; abdominal aortic aneurysm; contrast-enhanced ultrasound; endoleak; screening; ultrasound.

Figure 1

Three-dimensional contrast-enhanced ultrasound done intraoperatively for completion imaging after EVAR. A type I endoleak (arrow) as seen on the Curefab CS system workstation (Curefab, Munich, Germany) that was not identified on uniplanar angiography. Reprinted from Ormesher et al. (11), Copyright 2014, with permission from Elsevier.

Figure 2

EVAR follow-up, type II endoleak detection by color Doppler ultrasound. (A) Aortic cross-sectional view showing right and left limb with a hypoechoic right posterior channel within the aortic thrombus, color Doppler filling of this channel confirms the presence of an endoleak; (B) spectral analysis indicates bidirectional flow along the right posterior margin of the aorta consistent with a type II endoleak from a patent lumbar artery; (C) aortic cross-sectional view showing right and left limb and an anterior flow channel; and (D) spectral analysis indicates bidirectional flow at the anterior margin of the aorta consistent with a type II endoleak from the inferior mesenteric artery.