Respiratory-compensated non-contrast vs breath-hold contrast-enhanced MR angiography in pediatric Fontan patients

Objectives To compare a highly accelerated ECG-triggered and navigator-gated, non-contrast respiratory-compensated 3D magnetic resonance angiography with Dixon water–fat separation (NC-MRA) to respiratory-suspended non-ECG-triggered multiphase contrast-enhanced MRA (CE-MRA) in pediatric patients with partial or total cavopulmonary connection (PCPC/TCPC). Materials and methods In this prospective single-center study, between 02/2021 and 09/2023, 30 consecutive pediatric patients (mean age 3.6 ± 0.8 years) with PCPC or TCPC underwent 1.5 T cardiovascular MRI under deep sedation and mechanical ventilation. NC-MRA was acquired before contrast administration alongside standard CE-MRA. Two blinded readers independently evaluated image quality using a 5-point Likert scale and measured vascular diameters of predefined aortic segments, the Glenn anastomosis, Fontan conduit, and pulmonary arteries in consensus. Datasets were presented in randomized order. We used paired statistical testing for method comparison and Cohen’s kappa to assess inter-rater agreement. Results Mean NC-MRA acquisition time (5:55 ± 2:19 min) was comparable to that of multiphase CE-MRA (5:48 ± 3:03 min), including pre-contrast acquisition p = 0.54). Overall image quality was generally comparable between techniques for most vascular segments (NC-MRA median 5, IQR 5–5, CE-MRA median 5, IQR 4–5, p = 0.06–0.52). No significant differences were found in vascular diameter measurements across all segments ( p = 0.06–0.59). Inter-reader agreement was at least substantial (κ > 0.65). Conclusion Respiratory-compensated NC-MRA at 1.5 T provides image quality and vascular diameter measurements comparable to CE-MRA in pediatric PCPC/TCPC patients. Eliminating breath-holds and contrast administration, the technique simplifies workflow, avoids mechanical ventilation, and improves patient safety in this vulnerable population. Key Points Question Is a non-contrast, ECG-triggered, and navigator-gated 3D MRA sequence diagnostically equivalent to conventional breath-hold CE-MRA for vascular assessment in pediatric Fontan patients? Findings There were no significant differences in vascular diameters, and image quality was comparable between both sequences in most segments, showing substantial inter-rater agreement and diagnostic reliability . Clinical relevance Non-contrast, ECG-triggered, and navigator-gated MRA enables reliable vascular assessment in pediatric Fontan patients without gadolinium or breath-holds, reducing anesthesia requirements, improving safety, and simplifying workflow in this vulnerable population .