One specific velocity color mapping using optical coherence tomography.

Sergey G Proskurin,Anton Yu Potlov,Sergej V Frolov

doi:10.1117/1.jbo.20.5.051034

Abstract

Depth resolved coherence gating along with Doppler shift detection of the carrier frequency is used for one predetermined velocity mapping in different flows. Bidirectional rapid scanning optical delay of optical coherence tomography system is applied in the reference arm. Tilted capillary entry is used as a hydrodynamic phantom to model a sign-variable flow with complex geometry. Structural and one specific velocity images are obtained from the scanning interferometer signal processing in the frequency domain using analog and digital filtering. A standard structural image is decomposed into three parts: stationary object, and positive and negative velocity distributions. The latter two show equivelocity maps of the flow. The final image is represented as the complexation of the three.

Highlights

Direction sensitive investigation of reversible flows using phase sensitive technique was applied in acoustic reflectometry[1] and optical coherence tomography (OCT).[2]
The method of Doppler mapping of a chosen velocity is applied on the basis of low coherence depth discrimination of the reflected signal and detection of the introduced carrier frequency changes
It is possible to apply this approach in the study of small animals’ hearts where similar flows with complex geometry appear in nature

Summary

Introduction

Direction sensitive investigation of reversible flows using phase sensitive technique was applied in acoustic reflectometry[1] and optical coherence tomography (OCT).[2]. Velocity image reconstruction based on estimation of phase change between sequential A-scans is represented as the color or Doppler image in both. Cross-3 and auto-correlation[4,5,6,7,8,9] functions of the reflected signal are used. The OCT system presented in Ref. 3 is based on the calculation of cross-correlation function for a certain number, N, of adjacent A-scans. The mean phase shift variation is used as Δφ 1⁄4 · SÃiþ1;T ; (1). Si;T and SÃiþ1;T are the complex signals of adjacent A-scans. T is the temporal interval between the adjacent A-scans. The Doppler frequency is represented as fD

Methods

Results

Conclusion