University of Birmingham, Sci-Phy-4-Health Centre for Doctoral Training, College of Engineering and, United Kingdom.
University of Birmingham, College of Engineering and Physical Sciences, School of Computer Science,, United Kingdom.
J Biomed Opt. 2021 May;26(5). doi: 10.1117/1.JBO.26.5.056001.
High density diffuse optical tomography (HD-DOT) as applied in functional near-infrared spectroscopy (fNIRS) is largely limited to continuous wave (CW) data. Using a single modulation frequency, frequency domain (FD) HD-DOT has recently demonstrated better localization of focal activation as compared to CW data. We show that combining CW and FD measurements and multiple modulation frequencies increases imaging performance in fNIRS.
We evaluate the benefits of multiple modulation frequencies, combining different frequencies as well as CW data in fNIRS HD-DOT.
A layered model was used, with activation occurring within a cortex layer. CW and FD measurements were simulated at 78, 141, and 203 MHz with and without noise. The localization error, full width half maximum, and effective resolution were evaluated.
Across the average of the three metrics, at 141 MHz, FD performed 8.4% better than CW, and the combination of CW and FD was 21.7% better than CW. FD measurements at 203 MHz performed 5% better than 78 MHz. Moreover, the three combined modulation frequencies of FD and CW performed up to 3.92% better than 141 MHz alone.
We show that combining CW and FD measurements offers better performance than FD alone, with higher modulation frequencies increasing accuracy. Combining CW and FD measurements at multiple modulation frequencies yields the best overall performance.
高密度扩散光学断层扫描（HD-DOT）在功能近红外光谱（fNIRS）中的应用主要限于连续波（CW）数据。最近，频域（FD）HD-DOT 已被证明比 CW 数据具有更好的焦点激活定位能力。我们表明，结合 CW 和 FD 测量以及多个调制频率可提高 fNIRS 中的成像性能。
我们评估了在 fNIRS HD-DOT 中使用多个调制频率、结合不同频率以及 CW 数据的优势。
使用分层模型，在皮质层内发生激活。在有噪声和无噪声的情况下，分别在 78、141 和 203 MHz 处模拟 CW 和 FD 测量。评估了定位误差、半峰全宽和有效分辨率。
在三个指标的平均值中，141 MHz 时 FD 比 CW 好 8.4%，而 CW 和 FD 的组合比 CW 好 21.7%。203 MHz 的 FD 测量比 78 MHz 好 5%。此外，三个组合调制频率的 FD 和 CW 比单独的 141 MHz 好 3.92%。
我们表明，与 FD 相比，结合 CW 和 FD 测量可以提供更好的性能，而更高的调制频率可以提高准确性。在多个调制频率下结合 CW 和 FD 测量可获得最佳整体性能。
