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

我们开发了一种使用功能磁共振成像（fMRI）和近红外光谱（NIRS）技术的同步测量系统。采用3T核磁共振成像系统（GEYMS Signa Horizon LX）和光学成像系统（日立ETG-100）对22名年龄在21 ~ 43岁的正常志愿者进行了研究。将光缆束延伸至MR头圈，建立同步采集系统。不同的光模式和持续时间被用于视觉激活。使用事件相关功能磁共振成像（ER-fMRI）技术研究了人类初级视觉皮层（V1）短暂视觉刺激时血氧水平依赖（BOLD）反应的时间特征。通过在1到6秒之间改变反转棋盘的刺激持续时间来检测BOLD反应的大小和程度。此外，还评估了实测和预测的BOLD反应之间的关系。结果表明，峰值高度和基线以上面积随刺激时间的延长呈线性增加。视网膜定位和事件相关研究表明，这两个系统的反应定位和线性几乎相同。fMRI对比（BOLD）使用脱氧血红蛋白信息，NIRS同时使用脱氧血红蛋白和脱氧血红蛋白动态（两者之和称为总血红蛋白，与脑血容量相关）。同步测量系统提供并集成了脑生理参数（如CBF、CBV和CMRO2）的时空动态。

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).