Feasibility and accuracy of carbon dioxide Cone-Beam CT for post-operative evaluation in complex and standard EVAR.

Background and aim In Endovascular aneurysm repair (EVAR) lifelong post-operative surveillance, is considered an integral part of the treatment itself, traditionally performed via regular computed tomography angiography (CTA). Completion Carbon dioxide cone beam CT (CO2 CBCT) has emerged as a viable and safe alternative. This study evaluated the diagnostic concordance between CO2 CBCT and CTA in detecting endoleaks in patients undergoing simple and complex EVAR. Methods In this study 45 patients underwent CO2 CBCT as a completion imaging study following EVAR, with subsequent CTA follow-up. Diagnostic performance of the CBCT was assessed and concordance between the two modalities was quantified using Cohen's Kappa. The potential influence of procedural, anatomical and clinical variables on diagnostic concordance was also evaluated. Results CO2 CBCT demonstrated a sensitivity of 85.0% and specificity of 76.0%. The positive predictive value was 73.9% and negative predictive value (NPV) was 86.4%. Agreement between CO2 CBCT and CTA is classified as moderate (Cohen's κ=0.601). No procedural, anatomical or clinical variable demonstrated a statistically significant influence on the concordance among the two techniques. Conclusions CO2 CBCT demonstrated reliable diagnostic performance for endoleak detection following EVAR, with a particularly high NPV suggesting a potential role as a screening tool to safely exclude post-operative complications. The diagnostic concordance was independent of procedural variables. These findings support a more widespread use of CO2 CBCT as a completion imaging exam, and concomitant development of follow-up protocols that might space out initial imaging exams, allowing a reduction in cumulative CTA-related radiation and contrast exposure. Larger prospective multicentre studies are warranted to confirm these results.