Phelps Janelle E, Vishwanath Karthik, Chang Vivide T C, Ramanujam Nirmala
Department of Biomedical Engineering, Duke University, 136 Hudson Hall, Box 90281, Durham, NC 27708, USA.
Opt Express. 2010 Aug 30;18(18):18779-92. doi: 10.1364/OE.18.018779.
We developed a ratiometric method capable of estimating total hemoglobin concentration from optically measured diffuse reflectance spectra. The three isosbestic wavelength ratio pairs that best correlated to total hemoglobin concentration independent of saturation and scattering were 545/390, 452/390, and 529/390 nm. These wavelength pairs were selected using forward Monte Carlo simulations which were used to extract hemoglobin concentration from experimental phantom measurements. Linear regression coefficients from the simulated data were directly applied to the phantom data, by calibrating for instrument throughput using a single phantom. Phantoms with variable scattering and hemoglobin saturation were tested with two different instruments, and the average percent errors between the expected and ratiometrically-extracted hemoglobin concentration were as low as 6.3%. A correlation of r = 0.88 between hemoglobin concentration extracted using the 529/390 nm isosbestic ratio and a scalable inverse Monte Carlo model was achieved for in vivo dysplastic cervical measurements (hemoglobin concentrations have been shown to be diagnostic for the detection of cervical pre-cancer by our group). These results indicate that use of such a simple ratiometric method has the potential to be used in clinical applications where tissue hemoglobin concentrations need to be rapidly quantified in vivo.
我们开发了一种比率测量方法，能够从光学测量的漫反射光谱中估算总血红蛋白浓度。与总血红蛋白浓度最相关且不受饱和度和散射影响的三个等吸收波长比率对分别为545/390、452/390和529/390纳米。这些波长对是通过正向蒙特卡罗模拟选择的，该模拟用于从实验体模测量中提取血红蛋白浓度。通过使用单个体模校准仪器通量，将模拟数据的线性回归系数直接应用于体模数据。使用两种不同仪器对具有可变散射和血红蛋白饱和度的体模进行了测试，预期的和通过比率测量法提取的血红蛋白浓度之间的平均百分比误差低至6.3%。对于体内发育异常的宫颈测量，使用529/390纳米等吸收比率提取的血红蛋白浓度与可扩展的反向蒙特卡罗模型之间的相关性为r = 0.88（我们团队已证明血红蛋白浓度可用于诊断宫颈癌前病变）。这些结果表明，使用这种简单的比率测量方法有潜力应用于需要在体内快速定量组织血红蛋白浓度的临床应用中。
