Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States.
J Biomed Opt. 2019 Jan;24(1):1-4. doi: 10.1117/1.JBO.24.1.010502.
Phase wrapping is a crucial issue in Doppler optical coherence tomography (OCT) and restricts its automatic implementation for clinical applications that quantify total retinal blood flow. We propose an automated phase-unwrapping technique that takes advantage of the parabolic profile of blood flow velocity in vessels. Instead of inspecting the phase shift manually, the algorithm calculates the gradient magnitude of the phase shift on the cross-sectional image and automatically detects the presence of phase wrapping. The voxels affected by phase wrapping are corrected according to the determined flow direction adjacent to the vessel walls. We validated this technique in the rodent retina using a prototype visible-light OCT and in the human retina with a commercial infrared OCT system. We believe this signal processing method may well accelerate clinical applications of Doppler OCT in ophthalmology.
相位包裹是多普勒光相干断层扫描（OCT）中的一个关键问题，限制了其在用于量化总视网膜血流的临床应用中的自动实现。我们提出了一种自动相位解缠技术，该技术利用了血管中血流速度的抛物线分布。该算法不是手动检查相位偏移，而是计算横截面图像上相位偏移的梯度大小，并自动检测相位包裹的存在。根据血管壁相邻处确定的血流方向，对受相位包裹影响的体素进行校正。我们使用原型可见光 OCT 在啮齿动物视网膜中以及使用商业红外 OCT 系统在人视网膜中验证了该技术。我们相信这种信号处理方法可能会加速多普勒 OCT 在眼科中的临床应用。
