Coherent signal analysis in color Doppler optical coherence tomography

Color Doppler optical coherence tomography (CDOCT) is a recent innovation which allows spatially localized flow velocity mapping simultaneous with micro-structural imaging. We present a theoretical model for velocity image formation in CDOCT. The equivalence between the heterodyne detector current power spectrum in CDOCT and the optical source power spectrum is established. We show that stochastic modifications of the detected electronic spectrum by fluctuating scatterer distributions in the flow field give rise to unavoidable velocity estimation inaccuracies, as well as to the fundamental trade-off between the maximum velocity image acquisition rate and the estimated velocity precision. Novel algorithms which permit high fidelity depth-resolved measurements of velocities in turbid media with optimal frame rate are also reported.