Quantitative and qualitative CT features of coronary artery anomalies with an interarterial course: exploratory...

To compare quantitative and qualitative coronary CT angiography (CCTA) features in patients with coronary artery anomalies (CAAs) with an interarterial course and to explore their associations with exertional symptoms (ES). This retrospective single-centre study screened consecutive CCTA examinations performed between January 2020 and December 2025. After standard exclusions, 2,813 patients remained eligible, of whom 26 had CAAs with an interarterial course. Quantitative markers were stenosis percentage (SP) and ellipticity index (EI), and qualitative morphological features included slit-like ostium, acute take-off angle, and compression findings. For cohort-level analyses, patients without visually appreciable compression were assigned SP = 0% and EI = 1.0. Interobserver agreement and exploratory associations with ES were assessed. CAAs with an interarterial course were identified in 26/2,813 patients (0.9%); all involved the right coronary artery. ES were present in 18 patients (69.2%). Reproducibility was good for SP (ICC 0.86, 95% CI 0.68-0.95) and moderate for EI (ICC 0.58, 95% CI 0.19-0.83). Patients with ES had higher SP (35.8% [IQR 27.0-45.4] vs. 18.4% [0.0-20.3], p = 0.003) and higher EI (1.78 [1.54-1.94] vs. 1.54 [1.00-1.64], p = 0.045). SP was associated with ES (OR per 1% increase 1.09, 95% CI 1.01-1.17, p = 0.021), corresponding to an OR of 1.50 (95% CI 1.09-2.04) per 5% increase. SP showed exploratory discriminatory ability for ES (AUC 0.82, 95% CI 0.64-0.99). In this small exploratory cohort of right coronary artery anomalies with interarterial course, SP showed the most reproducible quantitative signal and the clearest association with ES. These findings should be interpreted as symptom-based anatomical associations rather than evidence of haemodynamic relevance and require validation against standardised functional testing.