Wang Qiang, Gong Peijun, Cense Barry, Sampson David D
Optical+Biomedical Engineering Laboratory, Department of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Highway, Perth WA 6009, Australia.
University of Surrey, Guildford, Surrey, GU2 7XH, UK.
Biomed Opt Express. 2018 Dec 19;10(1):293-307. doi: 10.1364/BOE.10.000293. eCollection 2019 Jan 1.
We present a new optical coherence tomography (OCT) angiography method for imaging tissue microvasculature based on the characteristic frequency-domain flow signature in a short time series of a single voxel. The angiography signal is generated by Fourier transforming the OCT signal time series from a given voxel in multiple acquisitions and computing the average magnitude of non-zero (high-pass) frequency components. Larger temporal variations of the OCT signal caused by blood flow result in higher values of the average magnitude in the frequency domain compared to those from static tissue. Weighting of the signal by the inverse of the zero-frequency component (i.e., the sum of the OCT signal time series) improves vessel contrast in flow regions of low OCT signal. The method is demonstrated on a fabricated flow phantom and on human skin and, at only 5 time points per voxel, shows enhanced vessel contrast in comparison to conventional correlation mapping/speckle decorrelation and speckle variance methods.
我们提出了一种新的光学相干断层扫描（OCT）血管造影方法，用于基于单个体素短时间序列中的特征频域血流特征对组织微血管进行成像。血管造影信号是通过对多次采集的来自给定体素的OCT信号时间序列进行傅里叶变换，并计算非零（高通）频率分量的平均幅度而生成的。与静态组织相比，由血流引起的OCT信号的较大时间变化导致频域中平均幅度的值更高。通过零频率分量的倒数（即OCT信号时间序列的总和）对信号进行加权，可改善低OCT信号流动区域中的血管对比度。该方法在制造的流动模型和人体皮肤上得到了验证，并且每个体素仅在5个时间点时，与传统的相关映射/散斑去相关和散斑方差方法相比，显示出增强的血管对比度。
