Which statement best describes the role of duplex ultrasound in EVAR surveillance?

• A. It is the primary modality for detecting endoleaks
• B. It is not used in EVAR surveillance
• C. It is used to monitor sac size and has limited sensitivity for endoleaks
• D. It replaces CT angiography for all surveillance

Answer: (C)

In EVAR surveillance, the key idea is that duplex ultrasound is used mainly to monitor the aneurysm sac size over time, while its ability to detect endoleaks is limited. It’s a noninvasive, radiation-free way to track changes in sac diameter and to some extent visualize flow patterns around the graft, but its sensitivity for identifying endoleaks is not high and can miss small or intermittent leaks. Because detecting and characterizing endoleaks accurately requires greater detail, CT angiography remains the preferred, more sensitive modality for endoleak detection and comprehensive graft assessment. Duplex thus serves as a useful adjunct for ongoing sac surveillance between CT scans, rather than replacing CT or serving as the primary method for endoleak detection.