Comparative view of reactive hyperemia perfusion changes in the upper-limb by laser Doppler flowmetry and optoacoustic tomography and meta-analysis

Laser Doppler flowmetry (LDF) is one of the most used technologies to access human in vivo blood perfusion. However, its single point measurement capacity in a depth that likely is lower than 1 mm, are major criticisms that limit its utility. New image-based techniques such as Optoacoustic Tomography (OAT) allow the non-invasive observation of larger tissue areas with greater spatial resolution. In this work, we compared synchronized LDF and OAT data during a Post-Occlusion Reactive Hyperemia (PORH) maneuver in the upper limb (occlusion of the brachial artery). Measurements were obtained in the volar forearm (OAT and LDF) and in the fingertip (LDF). All procedures respected the principles of good clinical practices for human research purposes. Results confirm that LDF and OAT signals are significantly correlated at the superficial plexus. LDF does not detect deeper vascular structures of the skin but, even so, it is still very useful to access perfusion in areas with higher capillary density such as the fingertip.