Incremental Anatomical Value of CT Angiography Beyond Echocardiography in the Preoperative Assessment of Pediatric Conotruncal Anomalies: A Surgical Correlation Study

Background: Conotruncal anomalies frequently involve extracardiac vascular structures that are critical for surgical planning yet incompletely assessed by transthoracic echocardiography (TTE). We evaluated the incremental diagnostic value of CT angiography (CTA) beyond TTE using intraoperative findings as the reference standard. Methods: In this single-center retrospective study, 239 children who underwent surgical repair of a conotruncal anomaly and had both preoperative TTE and CTA were analyzed. The incremental contribution of CTA was graded as none, minor, or major by two independent reviewers. Diagnostic performance of each modality was compared with operative findings for coronary artery anomalies, right aortic arch, aortic arch hypoplasia, interrupted aortic arch, and pulmonary artery atresia, non-confluence, and hypoplasia. Results: CTA provided incremental information beyond TTE in 232 patients (97.1%), classified as major in 51.9% and minor in 45.2%; interobserver agreement was almost perfect (quadratic-weighted κ = 0.825). CTA was superior for coronary artery anomalies (sensitivity 91.7% vs. 50.0%), branch pulmonary artery hypoplasia (97.3% vs. 89.3%), and aortic arch hypoplasia (100% vs. 87.5%; all p < 0.05), and identified aortopulmonary collaterals and a persistent left superior vena cava more frequently than TTE. The two modalities performed comparably for aortic arch sidedness and interrupted aortic arch, and pulmonary atresia. Conclusions: CTA provides additional, operatively confirmed anatomical information beyond TTE in the majority of children with conotruncal anomalies, with the greatest value for extracardiac vascular anatomy. Rather than replacing echocardiography, CTA should be regarded as a complementary modality that refines preoperative anatomical assessment.