Spectroscopic Doppler analysis for visible-light optical coherence tomography
Spectroscopic Doppler analysis for visible-light optical coherence tomography
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DOI：
10.1117/1.jbo.22.12.121702
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发表时间：
2017-12-01
影响因子：
3.5
通讯作者：
Zhang, Hao F.
中科院分区：
文献类型：
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作者：
Shu, Xiao;Liu, Wenzhong;Zhang, Hao F.
可见光光学相干断层扫描(VIS-OCT)可以有效地测量视网膜氧代谢速率，它分别通过光谱分析和多普勒测量来同时定量视网膜血管中的氧饱和度和血流量。多普勒OCT将连续A线之间的相位变化与散射介质的轴向流速联系起来。由于它的周期性，可检测的相移介于-pi和pi之间，这限制了在不进行相位展开的情况下可测量的最大明确速度。在波长较短的情况下，VIS-OCT更容易受到相位模糊的影响，因为流动引起的相位变化与探测光的中心波数线性相关。我们利用频谱多普勒分析消除了相位展开的需要。我们将整个VIS-OCT光谱分割成一系列窄子带，并重建VIS-OCT图像，以提取所有子带中对应的多普勒相移。然后，我们通过线性回归分析与子带相关的相移来量化流速。在体模实验中，我们发现光谱多普勒分析在不进行相位展开的情况下扩展了可测量的绝对相移范围。我们还测试了这种方法来量化啮齿动物体内的视网膜血流量。(C)2017年光学仪器工程师学会(SPIE)
Retinal oxygen metabolic rate can be effectively measured by visible-light optical coherence tomography (vis-OCT), which simultaneously quantifies oxygen saturation and blood flow rate in retinal vessels through spectroscopic analysis and Doppler measurement, respectively. Doppler OCT relates phase variation between sequential A-lines to the axial flow velocity of the scattering medium. The detectable phase shift is between -pi and pi due to its periodicity, which limits the maximum measurable unambiguous velocity without phase unwrapping. Using shorter wavelengths, vis-OCT is more vulnerable to phase ambiguity since flow induced phase variation is linearly related to the center wavenumber of the probing light. We eliminated the need for phase unwrapping using spectroscopic Doppler analysis. We split the whole vis-OCT spectrum into a series of narrow subbands and reconstructed vis-OCT images to extract corresponding Doppler phase shifts in all the subbands. Then, we quantified flow velocity by analyzing subband-dependent phase shift using linear regression. In the phantom experiment, we showed that spectroscopic Doppler analysis extended the measurable absolute phase shift range without conducting phase unwrapping. We also tested this method to quantify retinal blood flow in rodents in vivo. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)