Three-Dimensional Echocardiography

This brief overview relates to the recent introduction of real-time three-dimensional echocardiographic imaging techniques, which has revolutionized echocardiography, as images are obtained in just one beat. A great potential lies ahead as clinical applications are multiple. T H R E E D I M E N S I O N A L E C H O C A R D I O G R A P H Y In the past, routine clinical use of three-dimensional echocardiography has been hindered by the prolonged and tedious nature of data acquisition. Image processing is time consuming and requires dedicated manpower to generate three-dimensional reconstructions of the heart. The recent introduction of real-time three-dimensional echocardiographic imaging techniques has revolutionized echocardiography, as images are obtained in just one beat. Real-time three-dimensional imaging was initially performed using a sparse-array matrix transducer (2.5 or 3.5 MHz), which consisted of 256 non-simultaneously firing elements. This transducer acquired a pyramidal volume dataset measuring 60°x60° within a single heartbeat. Echocardiographic images were then displayed “on-line” using simultaneous orthogonal (B-scan images) as well as 2-3 parallel short-axis planes (C-scans). Similar to other 3D methods, the sparse-array transducer resulted in accurate left ventricular volumes, ejection fraction and mass when compared to gold standard techniques, such as magnetic resonance imaging (MRI) and radionuclide angiography. The sparse-array transducer was also used advantageously during stress testing, because all post-exercise images were simultaneously acquired during a single heart beat which was at higher peak stress heart rates compared to conventional stress tests. Full-matrix Array: A full-matrix array transducer (X4, Phillips Medical Systems, Andover, Massachusetts), which utilizes 3000 elements, has been developed. This has resulted in (1) improved side-lobe performance (contrast resolution), (2) higher sensitivity and penetration, and (3) harmonic capabilities which may be used for both gray scale and contrast imaging. In addition, this transducer displays “on-line” 3D volume-rendered images and is also capable of displaying two simultaneous orthogonal two-dimensional imaging planes (i.e., biplane imaging). EDITORIAL Hammersmith Hospital, London, UK HOSPITAL CHRONICLES 2008, 3(4): 159–160 Correspondence to: Petros Nihoyannopoulos, MD, FRCP Professor of Cardiology Hammersmith Hospital, Du Cane Road London W12 0HS, UK E-mail: p.nihoyannopoulos@imperial. ac.uk