Role of real-time three dimensional echocardiography in cardiovascular interventions

Over the past decade, three dimensional transoesophageal echocardiography (3D TOE) has emerged as the primary imaging modality used for guidance in catheter based cardiac interventions. This is because real-time (RT) 3D TOE images have high spatial and temporal resolution, which allows unique detailed views of cardiac structures. This additional structural information helps guide interventional procedures leading to safer and shorter procedures with higher technical success, decreased radiation exposure, and improved patient outcomes. 3D TOE is also highly mobile and can therefore be performed at the site of care, including the cardiac catheterisation laboratory and surgical suite. In this article we will introduce the technique of RT 3D TOE, describe general views, and then focus discussion on the contemporary use of RT 3D TOE in percutaneous procedures such as mitral balloon valvuloplasty, mitral valve repair with clips, left atrial appendage occlusion, atrial and ventricular septal defect closure, aortic valve replacement, and paravalvular leak occlusion. 3D TOE images are currently obtained using matrix array transducers with more than 3000 crystals, which combined with new processors allows the acquisition of real-time images without the need for offline reconstruction. With this transducer, three imaging modes are available: real-time full volumes imaging, live 3D, and multi-plane imaging. The choice of imaging mode used is determined by the structure that is being examined and the objectives of the study. Ideally images of the left ventricle, which would be used to determine size and function, are obtained using full volume mode. Images of smaller and more mobile structures such as heart valves, left atrial appendage, and fossa ovalis are best acquired using live 3D or live 3D zoom modes. However, colour acquisition, used to examine blood flows, is only available in the full volume acquisition mode, which limits its utility in real-time imaging as the 4–6 beat …