Echocardiographic Three-Dimensional Visualization of the Heart

To perform three-dimensional (3-D) reconstruction of the heart by ultrasound, we developed a novel rotating echocardiographic probe which, with computer assistance, allows “real” 3-D reconstruction of the beating heart from 62 standard fan shaped two-dimensional (2-D) images acquired at 2.903 degree increments of rotation around its central axis. To reconstruct 3-D images of the beating heart, an entire cardiac cycle was recorded from each transducer position with electrocardiographic gating; acquisition time is 75 to 123 seconds in normal sinus rhythm. For each frame of the cardiac cycle, the 62 images digitized in cylindrical coordinates were processed by a scan converter algorithm to reconstruct a 3-D cone of information in cartesian coordinates. From the 3-D matrices stored in the computer, 2-D echocardiographic images in any plane at specified times in the cardiac cycle, or throughout the entire cardiac cycle, can be derived and visualized. A computer workstation-based system was developed to create full 3-D perspective projections of the echocardiographic data based on a technique called ray tracing, and adapted for use in visualizing 3-D scalar fields. The 3-D images obtained in normal volunteers demonstrated that our system permits an accurate reconstruction of the heart with the same spatial and temporal resolution as the original 2-D echocardiograms without cumbersome external reference systems.