Application of dynamic indocyanine green perfusion imaging for evaluation of vasoactive effect of acupuncture: a preliminary follow-up study on normal healthy volunteers.

Background: Even though acupuncture has long been used for alleviating symptoms related to vascular insufficiency, the clinical effect of acupuncture on peripheral circulation has not been fully confirmed. In this study, we investigated whether a near-infrared optical imaging-based method can be used to evaluate the efficacy of the acupuncture procedure to induce changes in peripheral tissue perfusion. Methods: Two normal, healthy controls were treated with acupuncture on two acupoints (LI-4 and SI-3) three times within 1 week. At the first and third visits, participants were examined using indocyanine green (ICG) perfusion imaging before and 10 minutes after the acupuncture procedure. Blood perfusion of the hands was determined after intravenous bolus injection of ICG and dynamic analysis of the fluorescence signals by near-infrared imaging system. Results: The blood perfusion rates of the hands were markedly increased immediately after acupuncture at the first trial in both cases. The baseline perfusion rates of the hands measured at the third visit were higher compared to the original basal level in one case; there was no difference in baseline perfusion rates of both hands in another case. In both cases, there was no acute effect of acupuncture on hand perfusion at the third trial. Conclusions: These results collectively suggest a potential of the ICG perfusion imaging as an effective evaluation tool to validate the vasoactive effect of acupuncture.