There are few techniques that have influenced therapeutic strategies in modem cardiology to a similar extent as coronary arteriography. Bypass surgery as well as transluminal coronary angioplasty would not have been possible without coronary angiography serving as a 'midwife' in their evolu­ tion. Despite the widespread and long-standing use in clinical practice, however, the interpretation of coronary angiograms has not changed very much since the early days. Most angiogr~s are still reviewed in a visual and semi-quantitative and thus often very subjective way. In the face of an almost exploding field for interventional catheterization including thrombolysis, balloon dilatation, and other rapidly evolving techniques for transluminal revascularization or recanalization, a more detailed and quantitative analysis of coronary arteriograms is urgently required. In addition to the delineation of coronary morphology, we need dynamic and functional information about flow and perfusion to understand the physiological significance of anatomic abnormalities. Coronary arteriography contains and can provide most of this information. With the application of appropriate techniques, it can be made available in the catheterization laboratory even during the patient's investiga­ tion, thus facilitating and improving clinical decision making. Objective and reproducible analysis will furthermore enhance our understanding about the pathophysiology of coronary disease.