Ghijsen Michael, Rice Tyler B, Yang Bruce, White Sean M, Tromberg Bruce J
Laser Microbeam and Medical Program, Beckman Laser Institute, 1002 Health Sciences Road, Irvine, CA 92612, USA.
Department of Biomedical Engineering, University of California, Irvine, CA 92697, USA.
Biomed Opt Express. 2018 Jul 30;9(8):3937-3952. doi: 10.1364/BOE.9.003937. eCollection 2018 Aug 1.
In this work we introduce a modified form of laser speckle imaging (LSI) referred to as affixed transmission speckle analysis (ATSA) that uses a single coherent light source to probe two physiological signals: one related to pulsatile vascular expansion (classically known as the photoplethysmographic (PPG) waveform) and one related to pulsatile vascular blood flow (named here the speckle plethysmographic (SPG) waveform). The PPG signal is determined by recording intensity fluctuations, and the SPG signal is determined via the LSI dynamic light scattering technique. These two co-registered signals are obtained by transilluminating a single digit (e.g. finger) which produces quasi-periodic waveforms derived from the cardiac cycle. Because PPG and SPG waveforms probe vascular expansion and flow, respectively, in cm-thick tissue, these complementary phenomena are offset in time and have rich dynamic features. We characterize the timing offset and harmonic content of the waveforms in 16 human subjects and demonstrate physiologic relevance for assessing microvascular flow and resistance.
在这项工作中，我们引入了一种改进形式的激光散斑成像（LSI），称为固定透射散斑分析（ATSA），它使用单个相干光源来探测两种生理信号：一种与搏动性血管扩张有关（传统上称为光电容积脉搏波（PPG）波形），另一种与搏动性血管血流有关（在此称为散斑容积脉搏波（SPG）波形）。PPG信号通过记录强度波动来确定，而SPG信号则通过LSI动态光散射技术来确定。这两个共同记录的信号是通过对单个手指（例如手指）进行透射照明获得的，该手指会产生源自心动周期的准周期波形。由于PPG和SPG波形分别探测厘米厚组织中的血管扩张和血流，这些互补现象在时间上是错开的，并且具有丰富的动态特征。我们对16名人类受试者的波形定时偏移和谐波含量进行了表征，并证明了其在评估微血管血流和阻力方面的生理相关性。
