Stephan Bannikov

Background:  Endovascular aneurysm repair (EVAR) has become critical in the treatment of infrarenal abdominal aortic aneurysms because of its reduced perioperative morbidity compared to open repair.^1,2 These interventions, while effective, require continuous postoperative monitoring for complications such as endoleaks.³ The current approach centers around computed tomography angiography (CTA) because of its high diagnostic accuracy. Standard follow-ups typically require multiple CTAs within the first year and then regular interval CTAs indefinitely, with intervals determined by patient risk.⁴ Current surveillance is inconsistently applied and lacks structured alignment between imaging modality and clinical risk, leading to overuse of CTA and underutilization of complementary modalities. Emerging imaging techniques and computational methods offer potential to better align imaging strategies with patient-specific risk.⁵ However, these approaches remain inconsistently integrated into current surveillance frameworks, highlighting an opportunity to develop a more systematic approach to post-EVAR imaging.

Methods:  A literature review was conducted using PubMed, search terms included: “EVAR surveillance,” “endoleak imaging,” and “contrast-enhanced ultrasound EVAR.” Relevant guideline-based sections on post-EVAR surveillance were reviewed from UpToDate. Additional review was performed using ChatGPT’s Deep Research tool (“compare imaging modalities for endoleak detection after EVAR”).

Results:  Emerging imaging techniques provide distinct advantages that expand surveillance options beyond current protocols. Contrast-enhanced ultrasound (CEUS) enables real-time visualization of blood flow and is particularly sensitive to low-flow endoleaks.⁶ Radiomics applied to unenhanced CT utilizes feature extraction to detect subtle imaging patterns, suggesting that diagnostically relevant information may be present without contrast administration.⁷ Advances in CT technology, including photon-counting detectors⁸ and deep learning-based reconstruction⁹, improve image quality, reduce metal artifact, and allow for potential reduction in imaging phases.

Within existing guideline frameworks that already incorporate elements of risk stratification, these technologies can be integrated to better align imaging modality with clinical context.¹⁰ CEUS may be used as a primary modality for routine follow-up in low-risk patients or for monitoring type II endoleaks. Reduced-contrast or unenhanced CT approaches may serve as adjuncts in patients with renal risk or indeterminate findings. In higher-risk scenarios, such as sac expansion or suspected high-flow endoleaks, CTA remains appropriate, with newer acquisition and reconstruction techniques supporting more efficient protocols.

Conclusions: Current EVAR surveillance guidelines incorporate elements of risk stratification but remain predominantly CTA-centered. Standardizing these modality-specific pathways within guideline frameworks could reduce unnecessary contrast exposure, limit cumulative radiation, and improve patient adherence to long-term surveillance. Future efforts should focus on formalizing these pathways into consensus-driven algorithms and validating their impact on clinical outcomes.

Works Cited:

1. Chaikof, Elliot L., et al. “The Society for Vascular Surgery practice guidelines on the care of patients with an abdominal aortic aneurysm.” Journal of vascular surgery 67.1 (2018): 2-77.
2. Wanhainen, Anders, et al. “Editor’s choice–European Society for Vascular Surgery (ESVS) 2024 clinical practice guidelines on the management of abdominal aorto-iliac artery aneurysms.” European Journal of Vascular and Endovascular Surgery 67.2 (2024): 192-331.
3. Cifuentes, Sebastian, et al. “Management of endoleaks after elective infrarenal aortic endovascular aneurysm repair: a review.” JAMA surgery 158.9 (2023): 965-973.
4. Chaer, Rabih A., and Efthymios Avgerinos. “Endoleak Following Endovascular Aortic Repair.” UpToDate, edited by Connor R. F., Wolters Kluwer, 7 Apr. 2026. Accessed 16 Apr. 2026.
5. Smith, Tyler, and Keith B. Quencer. “Best practice guidelines: imaging surveillance after endovascular aneurysm repair.” American Journal of Roentgenology 214.5 (2020): 1165-1174.
6. Johnsen, Lydia, et al. “Contrast-enhanced ultrasound detects type II endoleaks during follow-up for endovascular aneurysm repair.” Journal of Vascular Surgery 72.6 (2020): 1952-1959.
7. Hu, Ge, et al. “Unenhanced computed tomography radiomics help detect endoleaks after endovascular repair of abdominal aortic aneurysm.” European Radiology 34.3 (2024): 1647-1658.
8. Gomollon, Ana Maria Turrion, et al. “Photon-counting detector CT angiography for endoleak detection after endovascular aortic repair: triphasic CT with true noncontrast versus biphasic CT with virtual noniodine imaging.” Investigative Radiology 58.11 (2023): 816-821.
9. Cai, Huasong, et al. “Enhancing image quality in computed tomography angiography follow-ups after endovascular aneurysm repair: a comparative study of reconstruction techniques.” BMC Medical Imaging 24.1 (2024): 162.
10. Brazzelli, Miriam, et al. “Contrast-enhanced ultrasound and/or colour duplex ultrasound for surveillance after endovascular abdominal aortic aneurysm repair: a systematic review and economic evaluation.” Health technology assessment 22.72 (2018): 1-220.