Linköping University, Department of Biomedical Engineering, Linköping, Sweden.
J Biomed Opt. 2021 Dec;27(7). doi: 10.1117/1.JBO.27.7.074708.
For optical methods to accurately assess hemoglobin oxygen saturation in vivo, an independently verifiable tissue-like standard is required for validation. For this purpose, we propose three hemoglobin preparations and evaluate methods to characterize them.
To spectrally characterize three different hemoglobin preparations using multiple spectroscopic methods and to compare their absorption spectra to commonly used reference spectra.
Absorption spectra of three hemoglobin preparations in solution were characterized using spectroscopic collimated transmission: whole blood, lysed blood, and ferrous-stabilized hemoglobin. Tissue-mimicking phantoms composed of Intralipid, and the hemoglobin solutions were characterized using spatial frequency-domain spectroscopy (SFDS) and enhanced perfusion and oxygen saturation (EPOS) techniques while using yeast to deplete oxygen.
All hemoglobin preparations exhibited similar absorption spectra when accounting for methemoglobin and scattering in their oxyhemoglobin and deoxyhemoglobin forms, respectively. However, systematic differences were observed in the fitting depending on the reference spectra used. For the tissue-mimicking phantoms, SFDS measurements at the surface of the phantom were affected by oxygen diffusion at the interface with air, associated with higher values than for the EPOS system.
We show the validity of different blood phantoms and what considerations need to be addressed in each case to utilize them equivalently.
为了使光学方法能够准确评估体内血红蛋白氧饱和度，需要有一种独立验证的类似组织的标准来进行验证。为此，我们提出了三种血红蛋白制剂，并评估了对其进行特征描述的方法。
使用多种光谱方法对三种不同的血红蛋白制剂进行光谱特征描述，并将其吸收光谱与常用的参考光谱进行比较。
使用光谱准直透射法对三种血红蛋白制剂在溶液中的吸收光谱进行了表征：全血、溶血血和亚铁稳定的血红蛋白。使用空间频域光谱（SFDS）和增强灌注和氧饱和度（EPOS）技术，同时使用酵母耗尽氧气，对由 Intralipid 组成的血红蛋白溶液和组织模拟体模进行了特征描述。
当分别考虑高铁血红蛋白和散射对其氧合血红蛋白和脱氧血红蛋白形式的影响时，所有血红蛋白制剂的吸收光谱都相似。然而，根据所用参考光谱的不同，拟合时会观察到系统差异。对于组织模拟体模，体模表面的 SFDS 测量会受到与空气界面处氧气扩散的影响，导致测量值高于 EPOS 系统。
我们展示了不同血液体模的有效性，以及在每种情况下需要考虑哪些因素才能等效地利用它们。
