A liquid-based skin and blood flow model for Doppler optical coherence tomography imaging

Doppler optical coherence tomography (DOCT) combines the imaging capabilities of OCT with functional velocity imaging and is used routinely to study skin in-vivo. The skin provides a window to monitor diseases; it has been shown that changes in skin blood flow and structure are indicative of systemic disease change and representative of disease status. This study aims to aid understanding and interpretation of DOCT images of skin with respect to vessel diameter, depth and blood flow. We have constructed a tissue model using glass capillary tubes suspended at an angle of 20 to the horizontal in an Intralipid-filled tank. The Intralipid was diluted to levels which represented optimal tissue and blood flow scattering parameters. Intralipid was then pumped through the tubes to represent blood flow. The angled nature of the tubes allowed flow imaging at various depths. DOCT images were recorded using a swept-source OCT system with 1300 nm central wavelength and 6 mu m axial resolution (OCMP1300SS, Thorlabs, Inc.). Data parameters extracted from images include velocity, penetration depth and their dependence on tube diameter, depth and flow. We have successfully demonstrated a tissue model that allows DOCT imaging of vessel diameter, depth and blood flow to be investigated.