Synchrotron radiation coronary microangiography in isolated perfused rat heart for evaluation of coronary vascular response

Visualization of vasoconstriction and vasodilatation of coronary arteries with vasoactive agents is a useful research tool for evaluation of coronary vascular reserve. Microangiography with spatial resolution in the micrometer range was carried out to depict coronary vascular response in a rat heart under Langendorff perfusion using a high-speed imaging system and a third generation 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 using a galvanometer based scanner. Microangiographic images were obtained without image blur and stored in a digital frame memory system with a 1024×1024-pixel, 10-bit format. In imaging experiments, the isolated rat heart was mounted on a steel cannula and perfused with oxygenated perfusion fluid. After iodine contrast agent injection into the ascending aorta, vasodilatation in small arteries was visualized in response to acetylcholine.