Three-Dimensional Echocardiography Girish S Shirali, John Simpson Abstract Advances in technology, specifically transducers, piezo-electrical materials, and software for manipulation and analysis of datasets, have laid the groundwork for major advances in the field of three-dimensional echocardiography (3DE) 3DE is now being used across the spectrum of patients with congenitally malformed hearts to improve delineation of anatomy It is now possible to rotate 3DE images into an anatomically correct orientation, such that structures that are located superiorly in the body are at the top of the display, and the diaphragmatic surface of the heart is at the bottom of the display Live 3DE is being used to guide interventional procedures The arena of quantitative echocardiography enters a new era with the increasing sophistication of 3D acquisitions and analytical software 3DE measurements of left ventricular volumes and ejection fraction are comparable to those obtained with magnetic resonance imaging (MRI) There is a learning curve with 3DE, although strategies have been developed to negotiate the steep portion of the learning curve Keywords Three-dimensional echocardiography; Congenital heart defects; Transesophageal echocardiography; Transthoracic echocardiography; Volumetrics Introduction Appreciation of complex intracardiac anatomy and spatial relationships is inherent to the diagnosis of congenitally malformed hearts Until recently, the ability of the clinician to image the heart by echocardiography was limited to two dimensions (2DE) The very nature of a 2DE slice, which has no thickness, necessitates the use of multiple orthogonal sweeps This requires the echocardiographer to mentally reconstruct the anatomy and translate this virtual image into the structure of the report to describe the findings It is not easy for an untrained observer to decipher the images obtained in the course of a sweep Furthermore, since myocardial motion occurs in three dimensions, 2DE techniques do not lend themselves to accurate quantitation Recognition of these limitations of 2DE led to research and clinical interest in three-dimensional echocardiography (3DE)