The goal of this research is to develop a digital angiographic technique for obtaining and quantitating x-ray contrast medium perfusion images of the myocardium. The potential significance of successful development of this methodology is substantial, since it may be possible to obtain serial images of the distribution of myocardial perfusion during the maximal hyperemic response at routine coronary angiography and eventually even during intravenous ventriculography. To this end a program of research is described which includes radiographic phantom studies, image processing algorithm development and animal model validation with the following specific objectives: 1) To develop a method for obtaining a videodensitometrically accurate image of myocardial perfusion following a selective coronary injection of contrast material using available digital angiographic technology. 2) To develop algorithms for quantifying the appearance, peak density and washout of contrast material in the myocardium and for display of these values in a useful form. 3) To establish the accuracy and relationship to regional myocardial blood flow of these quantified measurements by correlation with independent measurements of perfusion and by measurements during states of altered coronary physiology. This bench and animal laboratory program will permit development of techniques and assessment of reproducibility, accuracy and sensitivity with precisely controlled levels of flow and stenosis.