Laser Doppler Perfusion Imaging for Assessment of Skin Blood Perfusion After Acupuncture

Background: Despite its widespread use for centuries, there is still a lack of techniques to show the effects of acupuncture. Microcirculation is the basic physiological condition as it provides nutrition and oxygen to the cells. The laser Doppler technique has been used to measure the blood perfusion of micro blood vessels in human skin. A moving laser beam and detector can measure blood perfusion in a large area rapidly: laser Doppler perfusion imaging (LDPI), which is the most relevant technique in the field. Objective: To study the peripheral effects of acupuncture, changes in peripheral (hand) skin blood perfusion were observed using LDPI. Design, Setting, and Subjects: Measurements were carried out in Beijing, China, on 20 healthy participants (12 women and 8 men, aged 23-53 years) and in Graz, Austria, on 50 healthy volunteers (32 women and 18 men, aged 19-59 years). Intervention: Acupuncture in China was performed on Hegu (LI 4) or a control point on different days. In Austria, acupuncture was performed on Neiguan (PC 6) and a control point. Main Outcome Measures: Blood perfusion changes were observed in different intervals before, during, and after acupuncture. The hand was divided into 10 areas, and the change rates of blood perfusion in these different areas were obtained. The tip of the middle finger served as the measuring area in the Austrian part of the study. Results: Three different effects were found: holistic effects; local effects without significant differences between acupoint and control point; and effects along Meridians. Conclusions: Interactions between the 3 effects could be demonstrated and are discussed. The basis for new insights into Meridian theory is proposed.