INITIAL CLINICAL-EXPERIENCE - WITH DYNAMI C 3-DIMENSIONAL ECHOCARDIOGRAPHY (ECHO-CT) IN CHILDREN WITH CONGENITAL HEART-DEFECTS

A prototype computed tomographic echocardiographic imaging probe was e xamined for its usefulness in diagnosing congenital heart disease in p ediatric patients. A 64-element, phased-array, 5 Mhz, echocardiographi c transducer mounted on a sliding carriage was used transthoracically on various positions of the chest. The transducer moves from the outfl ow tract to the apex of the heart in .5 to 1.3 mms increments and reco rds a tomographic slice of the heart at each increment level. Parallel images are recorded at a frame rate of 25-30 images/s and are ECG- an d respiration-gated. At each level a complete cardiac cycle is recorde d. The images are digitized and stored in the image processing compute r which reconstructs the anatomic structures of the heart in a three-d imensional format by means of different gray-scales. 54 pediatric pati ents with a variety of congenital heart defects were examined. Good qu ality echocardiographic pictures were obtained in all but 2 of the 54 patients. In these, three-dimensional reconstruction of the heart-was possible from transthoracically acquired echocardiographic studies. Th e recorded cardiac chambers and valves could be displayed in a three-d imensional format in real-time (four-dimensionally). One could also di splay the heart in real-time in any desired plane and in up to 5 plane s simultaneously without having to change the transducer position on t he chest. Different parts of the heart could be displayed in a view si milar to the one a surgeon has during the operation. Between 40 and 13 0 tomographic slices per patient were recorded. Image acquisition took 3-5 min and three-dimensional reconstruction of various cardiac struc tures took 20-90 min. We conclude that the computed tomographic imagin g probe facilitates acquisition of echocardiographic data as multiple planes can be obtained without changing the position of the transducer -carrying carriage. Display of three-dimensional structures of the hea rt may enhance our understanding of cardiac anatomy.