In 16 patients which underwent PTCA of a right or left coronary artery, analysis of coronarographic image using the stecometer (a precise instrument measuring background coordinates) was performed. Segment of a coronary artery in which PTCA was performed, was estimated in projections: RAO 30 degrees and LAO 60 degrees with a cranial 30 degrees-45 degrees view before and after the procedure. Totally, 72 arteriograms were evaluated. Measurements data were processed by a computer under a written program. Obtained results were presented digitally as a coordinates list and graphically as automatically plotted by Digigraf, drawings in the scale of 10:1 or 20:1. Obtained results were convergent with the hitherto applied method of coronary arteries stenoses approximate assessment.