Abstract：
The utilization of continuous wave (CW) near-infrared spectroscopy (NIRS) device to measure non-invasively muscle oxygenation in healthy and disease states is limited by the uncertainties related to the differential path length factor (DPF). DPF value is required to quantify oxygenated and deoxygenated heme groups\' concentration changes from measurement of optical densities by NIRS. An integrated approach that combines animal and computational models of oxygen transport and utilization was used to estimate the DPF value in situ. The canine model of muscle oxidative metabolism allowed measurement of both venous oxygen content and tissue oxygenation by CW NIRS under different oxygen delivery conditions. The experimental data obtained from the animal model were integrated in a computational model of O2 transport and utilization and combined with Beer-Lambert law to estimate DPF value in contracting skeletal muscle. A 2.1 value was found for DPF by fitting the mathematical model to the experimental data obtained in contracting muscle (T3) (Med.Sci.Sports.Exerc.48(10):2013-2020,2016). With the estimated value of DPF, model simulations well predicted the optical density measured by NIRS on the same animal model but with different blood flow, arterial oxygen contents and contraction rate (J.Appl.Physiol.108:1169-1176, 2010 and 112:9-19,2013) and demonstrated the robustness of the approach proposed in estimating DPF value. The approach used can overcome the semi-quantitative nature of the NIRS and estimate non-invasively DPF to obtain an accurate concentration change of oxygenated and deoxygenated hemo groups by CW NIRS measurements in contracting skeletal muscle under different oxygen delivery and contraction rate.
摘要：
利用连续波（CW）近红外光谱（NIRS）设备来测量健康和疾病状态下的非侵入性肌肉氧合受到与差分路径长度因子（DPF）相关的不确定性的限制。通过NIRS测量光密度，需要DPF值量化含氧和脱氧血红素基团的浓度变化。结合动物和氧气运输和利用的计算模型的集成方法用于原位估计DPF值。肌肉氧化代谢的犬模型允许在不同的氧气输送条件下通过CWNIRS测量静脉血氧含量和组织氧合。将从动物模型获得的实验数据整合到O2运输和利用的计算模型中，并结合Beer-Lambert定律来估算骨骼肌收缩中的DPF值。通过将数学模型拟合到在收缩肌肉（T3）（Med）中获得的实验数据，发现DPF的值为2.1。Sci.体育。练习48（10）：2013-2020，2016）。根据DPF的估计值，模型模拟很好地预测了NIRS在相同的动物模型上测量的光密度，但血流不同，动脉血氧含量和收缩率(J.应用。Physiol.108：1169-1176，2010和112：9-19,2013），并证明了在估计DPF值时提出的方法的鲁棒性。所使用的方法可以克服NIRS的半定量性质，并非侵入性地估计DPF，以通过CWNIRS测量在不同的氧气输送和收缩率下收缩骨骼肌获得氧合和脱氧血液组的准确浓度变化。
