A MICROANGIOGRAPHIC TECHNIQUE USING SYNCHROTRON-RADIATION TO VISUALIZE DERMAL CIRCULATION IN-VIVO

Conventional angiography cannot resolve dermal small vessels with a di ameter of 200 mu m or less. In vitro microangiography is currently cha racterized by better spatial resolution than conventional angiography but does not allow visualization of the blood stream in dermal vessels in vivo. In this study, we introduce a novel synchrotron radiation mi croangiographic system for visualizing the structure of and blood flow in dermal microvessels in vivo repeatedly. We used monochromatic sync hrotron radiation with an energy just above the k-edge of iodine (33.3 keV) as an x-ray and a high-definition television camera system with a high-sensitivity image pick-up tube for detection. The 33.3-keV mono chromatic synchrotron radiation allows detection of a small amount of iodine, and the high-definition television camera system can resolve s mall vessels with high-spatial resolution and no loss of sensitivity. We performed synchrotron radiation angiography of superficial inferior epigastric arteries and their branches in nine rats, and of the cauda l artery in 14 rats, and compared angiographic images taken by the cur rent system with those taken by a conventional angiographic system in seven rats. With this new microangiographic technique, we could visual ize small dermal vessels with a diameter as low as 50 mu m. In additio n, repeated angiograms at baseline and under increasing body temperatu re could be obtained. This new microangiographic approach is expected to be very useful for the assessment of dermal circulation in patients .