FIG 20.2 Full-volume three-dimensional echocardiography (3DE) dataset from a patient with atrioventricular septal defect The quad screen displays the apical four-chamber view in the left upper quadrant, the apical threechamber view in the right upper quadrant, and the short axis of the heart in the left lower quadrant The 3DE image is shown in the right lower quadrant Here, the free walls of the heart have been cropped away, and the heart has been rotated to demonstrate an en face view of the ventricular septal defect (dashed line) as seen from right to left The canal ventricular septal defect extends beneath both the superior (S) and the inferior (I) bridging leaflets Quantification of Cardiac Structures Quantitative 2DE measurements are based on geometric formulas that rely on (frequently incorrect) assumptions regarding the shapes of cardiac structures In contrast, 3DE acquisitions have the potential to include entire structures, thus obviating assumptions regarding geometry Similarly, 3DE software has the potential to quantify cardiac structures accurately regardless of their shape The software represents the blood pool as a mesh of points and lines for every frame of acquisition, thus providing a moving cast of the cavity of the ventricle through the cardiac cycle This enables the computation of global and regional volumes, parametric displays of endocardial excursion, and timing of contraction Practical Considerations in Pediatrics Until recently, clinical 3DE experienced organic and unstructured growth, with significant variability in adoption and clinical use between programs In 2016 and 2017, a document reflecting consensus among experts belonging to the European Association of Cardiovascular Imaging and the American Society of Echocardiography was published.9 While that document provides details on the acquisition, display, and orientation of images and the added value of 3DE in specific defects, we have summarized key points below ... parametric displays of endocardial excursion, and timing of contraction Practical Considerations in Pediatrics Until recently, clinical 3DE experienced organic and unstructured growth, with significant variability in adoption and clinical use between programs