Summary

脑血流动力学和的光散射特性的同步评估<em>体内</em>大鼠脑使用多光谱漫反射成像

Published: May 07, 2017
doi:

Summary

脑血流和体内大鼠脑组织的光散射特性的同时评估用常规多光谱漫反射成像系统证明。

Abstract

The simultaneous evaluation of cerebral hemodynamics and the light scattering properties of in vivo rat brain tissue is demonstrated using a conventional multispectral diffuse reflectance imaging system. This system is constructed from a broadband white light source, a motorized filter wheel with a set of narrowband interference filters, a light guide, a collecting lens, a video zoom lens, and a monochromatic charged-coupled device (CCD) camera. An ellipsoidal cranial window is made in the skull bone of a rat under isoflurane anesthesia to capture in vivo multispectral diffuse reflectance images of the cortical surface. Regulation of the fraction of inspired oxygen using a gas mixture device enables the induction of different respiratory states such as normoxia, hyperoxia, and anoxia. A Monte Carlo simulation-based multiple regression analysis for the measured multispectral diffuse reflectance images at nine wavelengths (500, 520, 540, 560, 570, 580, 600, 730, and 760 nm) is then performed to visualize the two-dimensional maps of hemodynamics and the light scattering properties of the in vivo rat brain.

Introduction

多光谱漫反射成像是用于获得在皮质组织固有的光学信号(IOSS)的空间图的最常用的技术。 IOSS在体内脑电波中所见的主要归因于三个现象:在光吸收的变化和由于皮质血流动力学散射特性,这取决于降低或线粒体细胞色素氧化在吸收变化和变型中通过形态学改变诱导的光散射特性1。

在可见光(VIS)到近红外(NIR)的光谱范围内的光被有效地吸收,并通过生物组织散射。 体内脑的扩散反射光谱的特征在于,吸收和散射光谱。减小的散射系数μ在VIS到NIR波长范围内的结果的脑组织的S'以单调散射光谱表现出在较长波长荷兰国际集团较小幅度。减小的散射系数μ频谱S“(λ)可以近似为在幂律函数2,3的形式为μS”(λ)=α×λ-b。散射能力b为在活组织2,3与生物散射体的大小。组织和减少活皮层组织的生存能力的形态改变可影响生物散射体4,5,6,7,8,9的大小。

多光谱漫反射成像光学系统,可以从白炽灯里容易地构建GHT源,简单的光学部件,和一个单色电荷耦合器件(CCD)。因此,各种算法和多光谱漫反射成像光学系统已被用来评估皮质血流动力学和/或组织形态10,11,12,13,14,15,16,17,18。

这篇文章中描述的方法,被用于可视化两者血液动力学和体内使用常规多光谱漫反射成像系统的大鼠脑组织的光散射性质。这种方法比其它技术的优点是,以评估在两个脑血流和皮层组织时空变化的能力形态,以及它适用于各种脑功能障碍的动物模型。因此,该方法将是适当的创伤性脑损伤,癫痫发作,中风和缺血调查。

Protocol

动物保健,准备和实验方案是由东京农工大学的动物研究委员会的批准。对于这种方法,将大鼠圈养在受控环境中(24℃,12小时光照/黑暗周期),与食物和水可随意获得。 1.传统多光谱漫反射成像系统的构建摩9个的窄带光学干涉滤光器具有的中心波长500,520,540,560,570,580,600,730,和760纳米至机动滤光轮的过滤孔。 构建使用宽带白色光源,机动滤?…

Representative Results

从体内大鼠脑获取的漫反射的代表性光谱图像示于图3中的图像,在500,520,540,560,570和580nm处清楚地看到血管的密集网络在大脑皮层。的血管,在600,730中的图像中观察到的周围组织,和760纳米之间的对比度恶化反射光中的时间更长,NIR波长下吸收血红蛋白。 图4示出了暴露的大鼠脑的用于?…

Discussion

在这个协议中最关键的步骤是去除减薄头骨区域,使颅窗口的;这应该小心进行,以避免意外出血。这个步骤是为了获得高品质的多光谱扩散高精度反射图像重要。建议手术过程如果可能的话,使用立体显微镜。明胶海绵小块止血有用。

这篇文章中描述的光学系统穿过位于所述光源的前面的干涉滤光器的单色的光。这可以通过将所述滤光轮在摄像机镜头或CCD摄像机的前面进行?…

Divulgazioni

The authors have nothing to disclose.

Acknowledgements

Part of this work was supported by a Grant-in-Aid for Scientific Research (C) from the Japanese Society for the Promotion of Science (25350520, 22500401, 15K06105) and the US-ARMY ITC-PAC Research and Development Project (FA5209-15-P-0175).

Materials

150-W halogen-lamp light source Hayashi Watch Works Co., Ltd, Tokyo, Japan LA-150SAE
Light guide Hayashi Watch Works Co., Ltd, Tokyo, Japan LGC1-5L1000
Collecting lens Hayashi Watch Works Co., Ltd, Tokyo, Japan SH-F16
Interference filters l@500nm Edmund Optics Japan Ltd, Tokyo, Japan #65088
Interference filters l@520nm Edmund Optics Japan Ltd, Tokyo, Japan #65093
Interference filters l@540nm Edmund Optics Japan Ltd, Tokyo, Japan #65096
Interference filters l@560nm Edmund Optics Japan Ltd, Tokyo, Japan #67766
Interference filters l@570nm Edmund Optics Japan Ltd, Tokyo, Japan #67767
Interference filters l@580nm Edmund Optics Japan Ltd, Tokyo, Japan #65646
Interference filters l@600nm Edmund Optics Japan Ltd, Tokyo, Japan #65102
Interference filters l@730nm Edmund Optics Japan Ltd, Tokyo, Japan #65115
Interference filters l@760nm Edmund Optics Japan Ltd, Tokyo, Japan #67777
Motorized filter wheel  Andover Corporation, NH, USA FW-MOT-12.5
16-bit cooled CCD camera Bitran, Japan BS-40
Video zoom lens Edmund Optics Japan Ltd, Tokyo, Japan VZMTM300i
Spectralon white standard with 99% diffuse reflectance Labsphere Incorporated, North Sutton, NH, USA SRS-99-020

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Citazione di questo articolo
Nishidate, I., Mustari, A., Kawauchi, S., Sato, S., Sato, M. Simultaneous Evaluation of Cerebral Hemodynamics and Light Scattering Properties of the In Vivo Rat Brain Using Multispectral Diffuse Reflectance Imaging. J. Vis. Exp. (123), e55399, doi:10.3791/55399 (2017).

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