抄録
Two-dimensional (2D) echocardiography has become an indispensable diagnostic tool, because it can noninvasively display an arbitrary cross-section of a heart in real time. For a better understanding of heart motion and function, however, three-dimensional (3D) views are more desirable.
This paper presents a method for reconstructing 3D left ventricular images from 2D echocardiograms. Previously reported 3D reconstructions utilized rotated long-axis cross-sections or cross-sections tilted in regular sequence. Unfortunately, the image quality of a cross-section obtained in such a regular sequence is not always good. The present method is more flexible, because any cross-section with good quality may be used. A special manipulator with four degrees of freedom has been developed, so that 3D coordinates and the orientation of an ultrasonic probe can be obtained. Echocardiograms recorded in VTR are digitized and left ventricular contours are automatically extracted. If the image quality is too poor for automatic contour extraction, the tracing of contour by hand is used. Extracted contours are placed in proper spatial relationship by taking the position and the orientation of the probe into account. Then their projections or stereo pairs are displayed. For a further refinement, wiregrid models of contour surface are developed by interpolation. Hidden line elimination, smoothing and shading are effectively applied in the manner of computer graphics. Three-dimensional regional contractility and volume changes can be quantitatively calculated.
