The computer-aided quantitative analysis of co-ronary obstructions from digitized coronary cineangiograms is described. First, the assessment of the percentage diameter reduction from single view angiograms is discussed. This method requires the delineation of the contours of the artery and the analysis of the diameter function. Next, a densitometric method is described to transform the brightness values in the digital image into cali-brated X-ray absorption profiles, thus creating the possibility to assess percentage area reduction of obstructions from single views.