Computed tomography of the heart by ultrasound

The authors developed an echocardiographic transducer that allows acquisition of 50 standard two-dimensional images at 3.6 degree increments of rotation around its central axis from any acoustic window. To reconstruct three-dimensional images of the beating heart, an entire cardiac cycle was recorded from each transducer position, with automatic electrocardiogram (ECG)-gating. For each frame of the cardiac cycle, the 50 images digitized in cylindrical coordinates were processed to reconstruct a 3-D cone of information in Cartesian coordinates. From the 3-D matrices, 2-D images in any plane can be derived or full 3-D perspective projections can be visualized. An echocardiographic system was developed that allows a computed 3-D reconstruction of the beating heart without cumbersome external reference systems