DYNAMIC 3-DIMENSIONAL ECHOCARDIOGRAPHY WITH A COMPUTED-TOMOGRAPHY IMAGING PROBE - INITIAL CLINICAL-EXPERIENCE WITH TRANSTHORACIC APPLICATION IN INFANTS AND CHILDREN WITH CONGENITAL HEART-DEFECTS - ABSTRACTS

Objective-To assess the clinical applicability of a prototype computed tomographic echocardiographic imaging probe in paediatric patients wi th congenital heart disease. Design-A phased array echocardiographic t ransducer (64 elements, 5 MHz) mounted on a sliding carriage-was used transthoracically in various positions on the chest. The transducer mo ves from the outflow tract to the apex of the heart in 0.5 to 1.3 mm i ncrements and records a tomographic slice of the heart at each increme nt level. Parallel images are recorded at a frame rate of 25-30 images /s. At each level a complete cardiac cycle is recorded. The images are digitised and stored in the image processing computer, which reconstr ucts the anatomical structures of the heart in a three-dimensional for mat by means of different grey scales. Patients-45 paediatric patients (age range 3 days to 17 years) with various congenital heart defects who had been admitted to hospital for diagnostic or therapeutic cardia c catheterisation or surgery. Results-Good quality echocardiographic p ictures were obtained in all but two of the 45 patients. Three-dimensi onal reconstructions of the heart were possible from transthoracic ech ocardiograms. The recorded cardiac chambers and valves were displayed in three-dimensions in real time (four-dimensional). The heart was als o displayed in real time in any desired plane and in up to five planes simultaneously without having to change the position of the transduce r on the chest. Different parts of the heart were displayed in a view similar to that seen by a surgeon during an operation. Image acquisiti on took 3-5 minutes and three-dimensional reconstruction of various ca rdiac structures 20-90 minutes. Conclusions-The computed tomographic i maging probe facilitates acquisition of echocardiographic data as mult iple planes can be obtained from one transducer position. Display of t hree-dimensional structures of the heart may enhance the understanding of cardiac anatomy.