Coronary angiography in rats using synchrotron radiation

Monochromatic X-rays obtained from synchrotron radiation (SR), provide a high-quality tool for medical imaging including, coronary angiography. To pursue higher resolution in experimental coronary angiography, a smaller visual field had seemed to be inevitable. However, there are cases in which whole coronary angiography is preferable in order to investigate such vasomotor activities as coronary vasospasm. To meet these requirements, we are trying to develop a new type of SR coronary angiography using Langendorff excised rat hearts. Experiments were performed at Photon Factory Accelerator Ring (PF-AR), High Energy Accelerator Research Organization (KEK), Japan. SR was obtained from a 6.5 GeV electron beam. The energy of the monochromatic X-rays was 33.3 keV, which is just above the K-edge energy of iodine. Iodine (35%) was infused as a contrast material to the aorta at the rate of 1 ml/min for 1 s. In the image obtained from coronary angiography, the resolution was 13 μm and the width of the visual field 26 mm×26 mm. Whole heart coronary vasculature identifying small arteries down to those 100 μm in diameter was obtained in beating hearts. Arteries as small as 50 μm were identified in arrested hearts. This method of SR coronary angiography is useful for the investigation of whole coronary configurations simultaneously in one visual field to the level of microvasculature.