Organs within the body have the ability to regulate their own blood supply. Vasoconstriction decreases blood flow, while vasodilatation increases blood flow. Visualization of vasoconstriction and vasodilatation of coronary arteries with vasoactive agents is a useful research tool for evaluation of coronary vascular response. Microangiography with a spatial resolution in the micrometer range was carried out in isolated perfused rat hearts using a high-speed imaging system and a synchrotron radiation source at SPring-8. The imaging system was composed of an X-ray direct-conversion-type detector incorporating an X-ray SATICON pickup tube and a high-speed X-ray shutter. Microangiographic images were obtained and stored in a frame memory system with a 1024 × 1024-pixel, 10-bit format. In the imaging experiments, the isolated rat heart was mounted on a steel tube and perfused with oxygenated perfusion fluid. After iodine contrast agent injection into the ascending aorta, vasodilatation in small arteries was visualized in response to vasoactive agents.
