Concurrent fMRI and optical measures for the investigation of the hemodynamic response function
Concurrent fMRI and optical measures for the investigation of the hemodynamic response function
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DOI：
10.1002/mrm.20511
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发表时间：
2005-08-01
影响因子：
3.3
通讯作者：
Mayhew, JE
中科院分区：
文献类型：
--
作者：
Kennerley, AJ;Berwick, J;Mayhew, JE
功能磁共振成像(FMRI)信号的变化是基于脑血流量(CBF)和血容量(CBV)以及血液氧合的综合变化。在胡须刺激和高碳酸血症刺激后，我们通过同时进行fmrl和激光多普勒血流仪(LDF)或光学成像光谱分析(OIS)，研究了这些血流动力学参数在啮齿动物桶状皮质中的关系。在冠状fMRI图上观察到最大血氧水平依赖(BOLD)和CBV变化的位置不同，BOLD区域更浅。从Delta R-2(*)图推断，这个浅层的6.5%的基础血体积分数下降到更深的皮质层的4%(对应于总的血红蛋白基础体积Hbt(O)=110µM和67µM)。基线体积分布被用来对蒙特卡罗模拟(MCS)进行参数化，以解释2DOIS。由此发现，当MRI数据取自皮质浅层时，光学血容量测量(即，总血红蛋白的变化)与CBV-MRI测量等同。激活的光学测量显示，与在同一平面(覆盖右半球表面)进行的fMRI测量有良好的空间重叠。CBV和CBF的变化遵循CBV=CBFα的比例关系，平均值(x=0.38+/-0.06)。
Functional magnetic resonance imaging (fMRI) signal variations are based on a combination of changes in cerebral blood flow (CBF) and volume (CBV), and blood oxygenation. We investigated the relationship between these hemodynamic parameters in the rodent barrel cortex by performing fMRl concurrently with laser Doppler flowmetry (LDF) or optical imaging spectroscopy (OIS), following whisker stimulation and hypercapnic challenge. A difference between the positions of the maximum blood oxygenation level-dependent (BOLD) and CBV changes was observed in coronal fMRI maps, with the BOLD region being more superficial. A 6.5% baseline blood volume fraction in this superficial region dropped to 4% in deeper cortical layers (corresponding to total hemoglobin baseline volumes Hbt(o) = 110 mu M and 67 mu M, respectively), as inferred from maps of Delta R-2(*). Baseline volume profiles were used to parameterize the Monte Carlo simulations (MCS) to interpret the 2D OIS. From this it was found that the optical blood volume measurements (i.e., changes in total hemoglobin) equated with CBV-MRI measurements when the MRI data were taken from superficial cortical layers. Optical measures of activation showed a good spatial overlap with fMRI measurements taken in the same plane (covering the right hemisphere surface). Changes in CBV and CBF followed the scaling relationship CBV = CBF alpha, with mean (x = 0.38 +/- 0.06.