Contrast-enhanced ultrasound versus CT angiography for endoleak detection after EVAR: a reference-standard-aware...

To evaluate contrast-enhanced ultrasound (CEUS) for endoleak detection after endovascular aneurysm repair (EVAR) against CT angiography (CTA) or CTA-centered composite references, explicitly treating CTA as an imperfect reference standard.

We searched PubMed/MEDLINE, Europe PMC, Crossref, OpenAlex, and performed an institutional Embase/Scopus coverage audit through 13 May 2026, with citation checking from prior reviews and included-study bibliographies. Eligible studies included adults undergoing paired CEUS and CTA or CTA-centered reference imaging after EVAR. The primary estimand was apparent CEUS diagnostic performance for any endoleak at the paired-examination level. An approximate bivariate logit-normal random-effects model was used as the primary meta-analysis; separate logit random-effects models, leave-one-out analysis, source-basis sensitivity analysis, and paired discordance testing were prespecified support analyses.

Eighteen all-endoleak studies contributed 2064 participants and 2452 paired examinations. The bivariate model estimated CEUS sensitivity as 0.905 (95% CI 0.869-0.932) and specificity as 0.943 (95% CI 0.890-0.971). Separate logit random-effects estimates were similar: sensitivity 0.909 (95% CI 0.873-0.936; I² = 42.5%) and specificity 0.944 (95% CI 0.892-0.972; I² = 88.7%). Results were consistent in ≤ 30-day and CTA-only subsets. CEUS-positive/reference-negative discordance exceeded CEUS-negative/reference-positive discordance (116 vs 67; ratio 1.73; p = 0.00036).

CEUS shows high apparent diagnostic performance for post-EVAR endoleak detection against CTA-centered references, with sensitivity and specificity both approximately 91-94%. CEUS-positive/reference-negative discordance was more frequent than the reverse and may represent low-flow or delayed endoleaks not captured by CTA-centered reference imaging in some cases. However, substantial specificity heterogeneity and CTA-reference limitations argue against unqualified CTA replacement. CEUS is best supported as a CTA-sparing surveillance and adjudication tool in selected pathways, with CTA retained for baseline structural assessment, graft evaluation, procedural planning, and discordant or high-risk findings.