Evaluation of Cerebral Hemodynamics and Tissue Morphology of In Vivo Rat Brain Using Spectral Diffuse Reflectance Imaging
Evaluation of Cerebral Hemodynamics and Tissue Morphology of In Vivo Rat Brain Using Spectral Diffuse Reflectance Imaging
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DOI：
10.1177/0003702816657569
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发表时间：
2017-05-01
影响因子：
3.5
通讯作者：
Sato, Manabu
中科院分区：
文献类型：
--
作者：
Nishidate, Izumi;Ishizuka, Tomohiro;Sato, Manabu
我们研究了基于漫反射光谱成像技术的体内皮层组织在可见光至近红外波长范围内的减少散射系数mu(s)′（lambda）和吸收系数mu(a)（lambda）的定量成像。在该方法中，在9个波长（500、520、540、560、570、580、600、730和760 nm）处获得体内皮质组织的漫反射图像。然后利用蒙特卡罗模拟对吸光度光谱的多元回归分析来估计皮质组织的光学系数。本分析计算了氧合血红蛋白和脱氧血红蛋白的浓度、散射振幅a和散射功率b，并根据估计的氧合血红蛋白和脱氧血红蛋白的浓度推导出吸收系数谱。约化散射系数谱由估计的散射振幅和散射功率决定。由估计的散射功率b计算微结构的粒度分布，定量评价脑组织的形态变化。暴露在大鼠脑内的动物实验表明，高氧和缺氧条件下的吸收特性的反应符合预期的众所周知的皮质血流动力学。平均颗粒大小在缺氧后立即明显减小，随后又由增大转为增大，说明脑组织组织活力丧失导致细胞和亚细胞结构肿胀和收缩。
We investigated a quantitative imaging of reduced scattering coefficients mu(s)'(lambda) and the absorption coefficients mu(a)(lambda) of in vivo cortical tissues in the range from visible to near-infrared (NIR) wavelengths based on diffuse reflectance spectral imaging technique. In this method, diffuse reflectance images of in vivo cortical tissue are acquired at nine wavelengths (500, 520, 540, 560, 570, 580, 600, 730, and 760 nm). A multiple regression analysis aided by the Monte Carlo simulation for the absorbance spectra is then utilized to estimate the optical coefficients of cortical tissue. This analysis calculates the concentration of oxygenated hemoglobin and that of deoxygenated hemoglobin, the scattering amplitude a and the scattering power b. The spectrum of absorption coefficient is deduced from the estimated concentrations of oxygenated hemoglobin and deoxygenated hemoglobin. The spectrum of reduced scattering coefficient is determined by the estimated scattering amplitude and scattering power. The particle size distribution of microstructure is calculated from the estimated scattering power b for evaluating the morphological change in brain tissue quantitatively. Animal experiments with in vivo exposed brain of rats demonstrated that the responses of the absorption properties to hyperoxic and anoxic conditions are in agreement with the expected well-known cortical hemodynamics. The average particle size was significantly reduced immediately after the onset of anoxia and then it was changed into an increase, which implied the swelling and shrinkage of the cellular and subcellular structures induced by loss of tissue viability in brain tissue.