Doppler velocity detection limitations in spectrometer-based versus swept-source optical coherence tomography.

Area of Science:

• Biomedical Optics
• Medical Imaging
• Ophthalmology

Background:

• Doppler techniques enable high-sensitivity imaging of biological flow.
• Accurate measurement of blood velocities and vascular perfusion is crucial in diagnostics.

Purpose of the Study:

• Compare spectrometer-based and wavelength-swept Doppler OCT for flow imaging.
• Characterize lower and upper observable velocity limits, including washout and phase wrapping effects.
• Determine the primary factor limiting maximum detectable Doppler velocity.

Main Methods:

• Theoretical comparison of Doppler OCT implementations.
• Experimental characterization using phantom flow and retinal blood flow data.
• Analysis of signal degradation and fringe washout effects.

Main Results:

• The fringe washout limit, not phase wrapping, determines the maximum detectable Doppler velocity.
• Wavelength-swept Doppler OCT demonstrates superior performance for high flow rates.
• Established clear differentiation between washout and phase wrapping phenomena.

Conclusions:

• Wavelength-swept Doppler OCT is superior for imaging high blood flow rates.
• Understanding velocity limits and washout is critical for accurate quantitative and qualitative flow imaging.
• This work provides crucial insights for optimizing Doppler OCT systems.