ASSESSMENT OF CONGENITAL HEART-DEFECTS BY DYNAMIC 3-DIMENSIONAL ECHOCARDIOGRAPHY - METHODS OF DATA-ACQUISITION AND CLINICAL POTENTIAL

To evaluate the use of three-dimensional (3D) echocardiography in the diagnosis of congenital heart defects, we studied 238 patients aged 3 days to 19 years (mean 4.3 years) with normal hearts (n = 13) or a variety of congenital heart defects (n = 225). Three different modalities of data acquisition suitable for 3D reconstruction were applied. For parallel scanning, the transducer is held in a 6-cm long scan frame and then moved over the thorax, or in the subcostal position, by a stepper motor using 0.5-mm steps with acquisition of perpendicular parallel images of the heart. For rotational scanning, the transducer is rotated at sectors of 2 degrees over a span of 180 degrees. For fan-like scanning, the transducer is moved in an arc 45 degrees each way from its vertical axis. Movement of the transducer is computer-controlled and performed with electrocardiographic and respiratory gating. Between 80 and 120 slices of the heart are thus obtained, which form the 3D dataset. This dataset can then be ''sectioned'' in any desired plane, thus permitting generation of views simulating intraoperative perspectives. Ventricular septal defects and atrioventricular valves can be displayed as viewed via the atrium. Muscular ventricular septal defects can be viewed as seen through a ventriculotomy. Obstruction in the left ventricular outflow tract can be viewed as via an aortotomy, and so on. We conclude that this new imaging modality has a vast potential and may facilitate planning of intracardiac surgery.