Establishment of the Measurement lhchnique for Cerebral Blood Flow and Metabolism during Brain Activation using MRI and Nearinfrared Spectroscopy.

我们开发了一个同时使用功能磁共振成像（fMRI）和近红外光谱（NIRS）技术的测量系统。22名年龄在21 ~ 43岁的正常志愿者，使用3 T MRI系统（GEYMS Signa Horizon LX）和光学成像系统（Hitachi ETG-100）进行研究。将光缆束延伸到MR头部线圈，建立同步采集系统。各种光模式和持续时间用于视觉激活。采用事件相关功能磁共振成像（ER-fMRI）技术，研究了视觉短时刺激对初级视皮层（V1）血氧水平依赖性（BOLD）反应的时间特征。BOLD反应的幅度和程度通过改变1至6秒之间的反转棋盘的刺激持续时间来检查。此外，测量和预测的BOLD响应之间的关系进行了评价。结果表明，峰高和基线以上的面积作为刺激持续时间的函数线性增加。视网膜定位和事件相关的研究表明，这两个系统的本地化和线性的反应几乎是相同的。功能磁共振成像对比（BOLD）使用脱氧血红蛋白信息，近红外光谱（NIRS）使用氧合血红蛋白和脱氧血红蛋白动力学（这些总和称为总血红蛋白，与脑血容量相关）。同时测量系统提供并整合关于脑生理参数的空间和时间动态（例如，CBF、CBV和CMRO 2）。

We have developed a simultaneous measurement system using functional magnetic resonance imaging (fMRI) and near-infrared spectroscopy (NIRS) technique. Twenty-two normal volunteers aged 21 to 43 were studied with a 3T MRI system (GEYMS Signa Horizon LX) and an optical imaging system (Hitachi ETG-100). Optical cable-bundle was extended to the MR head-coil to set up the simultaneous acquisition system. Various photic patterns and durations were used for the visual activations. The temporal characteristics of blood oxygenation level-dependent (BOLD) responses to brief visual stimulation of the human primary visual cortex (V1) were investigated using an event-related functional magnetic resonance imaging (ER-fMRI) technique. The magnitude and extent of the BOLD response were examined by changing the stimulus duration of a reversing checkerboard between 1 to 6 secs. In addition, the relationship between measured and predicted BOLD responses was evaluated. Results show that the peak height and the area above the baseline increased linearly as a function of stimulus duration. Retinotopic and event-related studies showed that the localization and linearity of the responses with these two systems were nearly identical. The fMRI contrast (BOLD) uses deoxyhemoglobin information, and NIRS uses both oxyhemoglobin and deoxyhemoglobin dynamics (the sum of these are named total hemoglobin, related to cerebral blood volume). Simultaneous measurement system provides and integrates the spatial and temporal dynamics with respect to the brain physiological parameters (e.g., CBF, CBV, and CMRO2).