Validation and visualization of two-dimensional optical spectroscopic imaging of cerebral hemodynamics.
Validation and visualization of two-dimensional optical spectroscopic imaging of cerebral hemodynamics.
复制标题
脑血流动力学二维光学光谱成像的验证和可视化。
DOI：
10.1016/j.neuroimage.2008.09.060
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发表时间：
2009
期刊：
影响因子：
5.7
通讯作者：
Toga,ArthurW
中科院分区：
文献类型：
--
作者：
Sheth,SameerA;Prakash,Neal;Guiou,Michael;Toga,ArthurW
基于灌注的功能性脑成像技术，如fMRI和光学本征信号（OIS）成像在神经科学研究和术中脑成像中变得越来越重要。最近的研究已经将光谱方法应用于OIS成像数据，我们将其称为“二维光学光谱”（2DOS），生成血红蛋白氧合和血容量功能变化的图像。这种改进是以几个假设为代价的。光纤光谱学的“黄金标准”技术是在一个光谱轴上分解反射光，而2DOS通过获取多个波长的图像来保留两个空间维度，牺牲光谱分辨率来获得额外的空间维度。此外，2DOS数据是在试验内或试验之间交错获取的，但在光谱分析期间合并，就像同时获取一样。到目前为止，采用这种方法的少数研究都假设降低的光谱分辨率是可以容忍的，并且足够的试验平均可以补偿暂时交错的数据采集。为了验证这些假设，我们通过观察麻醉大鼠后肢电刺激对初级体感觉皮层的血流动力学反应，将2DOS结果与传统纤维光谱结果进行了比较。比较显示，两者之间的拟合残差较低，相关性较高，但在响应幅度上存在显著差异。对单个时间过程的检查显示，2DOS数据的信噪比较低。为了可视化和解释2DOS图像，我们提出了一种参数化的可视化策略，其中氧、脱氧和总血红蛋白被分配到单独的颜色通道。由此产生的复合图像方便地显示了通过实质和血管室的血流动力学反应在空间和时间上的演变。
Perfusion-based functional brain imaging techniques such as fMRI and optical intrinsic signal (OIS) imaging are becoming increasingly important in both neuroscience research and intraoperative brain mapping. Recent studies have applied a spectroscopic approach to OIS imaging data, which we will call “two-dimensional optical spectroscopy” (2DOS), generating images of functional changes in hemoglobin oxygenation and blood volume. This improvement comes at the cost of several assumptions. Whereas the “gold standard” technique of fiber spectroscopy decomposes reflected light over a spectral axis, 2DOS retains both spatial dimensions by acquiring images at several wavelengths, sacrificing spectral resolution for the extra spatial dimension. Furthermore, 2DOS data are acquired interleaved within or between trials, but combined during the spectroscopic analysis as if acquired simultaneously. Thus far, the few studies employing this approach have assumed both that the reduced spectral resolution is tolerable, and that sufficient trial averaging can compensate for the temporally staggered data acquisition. To test these assumptions, we compared 2DOS results to those produced by traditional fiber spectroscopy by observing the hemodynamic response to hindpaw electrical stimulation over primary somatosensory cortex in anesthetized rats. Comparisons revealed low fitting residuals and a high level of correlation between the two, but noteworthy differences in response magnitudes. Inspection of individual timecourses revealed a lower signal-to-noise ratio for 2DOS data. For visualization and interpretation of the 2DOS images, we present a parameterized visualization strategy, in which oxy-, deoxy-, and total hemoglobin are assigned to individual color channels. The resulting composite image conveniently displays the evolution of hemodynamic responses through parenchymal and vascular compartments in space and time.