Laminar flow velocity estimation by the use of narrow-band electronics with optical coherence tomography

Doppler optical coherence tomography (DOCT) technique is a new extension to the current OCT developments, that is capable of determining the frequency shift due to the moving scatterers, making it possible to map out the localised blood flows and vessels beneath tissue surface. Doppler OCT system, being employed with a broadband detection electronics to measure frequency shift, is more complex than a narrowband OCT system, because a follow up filter is needed to overcome its low signal-to-noise ratio (SNR) for structure imaging. We describe a simple technique to estimate accurately the laminar flow velocity by the use of narrowband OCT system that is simpler and has a high SNR. It utilises the limited band of electronics to reconstruct the whole laminar velocity profile across target by the use of the least square curve fitting technique. The experimental results demonstrate that the estimated velocity profile by using this method correlate very well with the theoretical predictions. It may, therefore, allow the simpler OCT system to determine the flow velocity functionally in a simple and economic way for monitoring blood flow in vivo.