Development of Fingertip Synchrotron Radiation Microangiography toward Clinical Prediction of Diabetic Microangiopathy

The spatial resolution of conventional angiographic systems is not enough to predict diabetic microangiopathy in arterioles (20-200 µm).To determine whether fingertip synchrotron (SR) radiation microangiography has enough spatial resolution to quantitate arteriolar diameter changes, and whether an arteriolar paradoxical vasoconstriction is a characteristic observation for diabetic microangiopathy, diameter reduction as arteriolar branching and difference of the diameter changes induced by acetylcholine between control (n = 5) and diabetic rats (n = 5) were analyzed.Fingertip SR microangiography visualized the arterioles with a diameter range of 30-300 µm and demonstrated vascular diameter reduction as branching with a fixed ratio (r = 0.93, P0.004 and r = 0.73, P0.001). A vasodilatory reaction was induced by acetylcholine in the control (142.4 ± 61.9 to 190.9 ± 73.5, P0.05, n = 25), in contrast, paradoxical vasoconstriction in diabetic rats (201.6 ± 83.0 to 16 0.4 ± 67.9, P0.05, n = 37). Histological angiopathy was noted only in the diabetic rats.In conclusion, the fingertip SR microangiography is useful to predict diabetic micrangiopahty.