Precise and reproducible quantification of ventricular function and volume, particularly right ventricular volumetry, is important in congenital heart disease. Accurate quantification is highly dependent on accurate delineation of myocardial borders. Ferumoxytol-enhanced MUSIC provides multiphase, high resolution, dynamic 3D imaging of the whole heart. We evaluated the precision and reproducibility of ventricular function and volumetric measurements using a commercial 3D image design and modeling software whose segmentation algorithm takes into account partial volume effects (Mimics, Materialise). We demonstrate that quantification of ventricular function and volumetry for 4D MUSIC images using Mimics is reproducible with high intra-class correlation coefficient.