COMPUTER-ANALYSIS OF MOVING RADIOPAQUE MARKERS FROM X-RAY CINEFILMS

An application of digital image analysis techniques concerning the analysis of sequences of X-ray images is described. Information about the contraction pattern of the human heart can be extracted from an X-ray cinefilm by determining the trajectories of radiopaque markers that are sutured to the epicardium. Small regions of interest with predicted positions are digitized in each frame. Within a region the marker is detected with a method implying an adaptive threshold and an adaptive binary template. In the first two frames a region growing technique is used. Both procedures are discussed in detail. Implementation as part of the Cardiac Image Analysis System is described and a practical evaluation is given in terms of reproducibility, accuracy, and computation time on the PDP-11/10 based system. © 1979 Academic Press, Inc.