We have developed dynamic intravenous coronary arteriography (IVCAG) using a monochromatic (33.3 keV), 2-dimensional X-ray beam (70×70 mm) generated from synchrotron radiation. To investigate its use to visualize the coronary arteries and to estimate coronary blood flow, we performed IVCAG in 10 dogs and 1 goat. The animals were irradiated with the synchrotron beam after intravenous injection of a contrast agent, and images were obtained using a TV camera and videorecorder. In the dogs, blood flow in the left anterior descending coronary artery (LAD) was also estimated from the images by applying a transit-time analysis. We obtained dynamic IVCAG images in the dogs and goat and could visualize even a deliberately created coronary stenosis about 1 mm in length. In addition, coronary blood flow could be estimated with an acceptable degree of accuracy. LAD flow calculated from IVCAG was 14.7±5.1 ml/min, whereas measured LAD flow was 16.6±4.8 ml/min. There was a close correlation between the estimated and measured LAD flows (r=0.90, p<0.01). Thus, dynamic IVCAG is minimally invasive, permits the simultaneous evaluation of coronary anatomy and blood flow, and may be feasible for clinical application. (Jpn Circ J 1997; 61: 432 - 440)