Whole heart non-contrast 4D Flow MRI at 3.0T for clinical follow-up of congenital heart disease in children and adolescents.

AIMS: Cardiac MRI is central to evaluating ventricular function and hemodynamics in pediatric congenital heart disease (CHD). Conventional two-dimensional phase-contrast (2D-PC) imaging is challenged by fixed planes, operator dependence, and multiple breath-holds, where four-dimensional flow (4DF) MRI overcomes these challenges. This study compares accelerated whole heart 4D Flow (WH-4DF) MRI with 2D-PC and volumetric measurements in routine clinical follow up of pediatric CHD and highlights its applicability. METHODS AND RESULTS: For this prospective study seventy-one consecutive pediatric patients (median age 14 ± 2.4 years; 49 male) with surgically corrected CHD underwent both 2D-PC and accelerated WH-4DF MRI. Planning and acquisition times and overall success rate were recorded. Flow, velocity and volumetric measurements were compared using Bland-Altman analysis, orthogonal regression, and intraclass correlation coefficients. WH-4DF showed excellent agreement with 2D-PC and short-axis volumetry for aortic, pulmonary, and ventricular stroke volumes (mean differences <5%). Mean planning and acquisition time for WH-4DF was 10.3minutes (SD 1.1), where planning and acquisition time of 2D-PC was 11.2minutes (SD 6.25). Aliasing was observed in 11% of the WH-4DF acquisitions but did not compromise interpretability. CONCLUSIONS: Accelerated WH-4DF MRI is clinically robust and broadly applicable across CHD, including complex postoperative anatomies. It provides comparable numbers to 2D-PC, reproducible, and time-efficient flow quantification with superior coverage and reduced operator dependence. A single WH-4DF scan can replace multiple 2D-PC acquisitions with comparable results and may enhance assessment of regurgitant flow. These features underscore its potential role in routine clinical practice and in advancing our understanding of disease processes.