Light-pen computer processing of video image for the determination of left ventricular volume

A volume angiography system for on-line computation of left ventricular angiograms has been developed utilizing a video disc recorder, a light-pen unit, and a digital computer. The video disc recorder allows for immediate replay and stop-motion of ventricular angiograms on a video monitor. The light-pen is used by a technician/physician operator to define the margins of the ventricular chamber and input the data directly to the digital computer. The computer, utilizing the arealength method, applies preset magnification factors and calculates the ventricular volume. Comparison of this light-pen computer system with conventional manual processing of cine film yielded a correlation coefficient of 0.99. The equipment configuration employed in this system offers the advantages of available hardware components and operational simplicity. The major benefit has been avoidance of the logistic delays involved in cine film processing and handling, which have been obviated by the on-line capability of the video disc, light-pen, and computer combination.