STUDY ON BRAIN HEMODYNAMICS BY SIMULTANEOUS MEASUREMENT OF FUNCTIONAL MRI AND NEAR-INFRARED SPECTROSCOPY

功能MRI与近红外光谱同时测量脑血流动力学研究

• 批准号: 09680838
• 负责人: YAMAMOTO Toru
• 金额: $ 1.86万
• 依托单位: HOKKAIDO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09680838/
• 关键词: magnetic resonance; MRI; near-infrared spectroscopy; brain function

The purpose of this study was to understand brain hemodynamics in response to neuronal activation using simultaneous measurement of functional MRI (fMRI) and near-infrared spectroscopy (NIRS). Firstly, to improve detection of areas reflecting hemodynamic changes, artifacts in fMRI were analyzed. Secondly, probes of MRS were implemented into MRI bore for simultaneous measurements of MRI and NIRS during finger tapping tasks. Based on the observed results of two different techniques, the brain hemodynamics was explained.(1) We introduced a new analysis of artifacts in fMRI based on thermal noise intensity to quantitatively evaluate the efficacy of countermeasures against artifacts. It was demonstrated that both the task-related motion and the major influence of respiration are global head motion, which can be corrected by the motion correction software (SPM), having their own properties of time-intensity changes in pixels of the artifacts. True reduction of the influence of pulsation is essential for artifact-free fMRI.The efficacy of the motion correction of 8PM was also evaluated quantitatively. A pitfall dependent on image-spatial resolution was revealed. One-mm spatial resolution is necessary for the sufficient motion correction.(2) The simultaneous measurement of fMRI and NIRS showed that depicted areas reflecting BOLD type changes in fMRI were explained by changes of deoxygenated hemoglobin (deoxyHb) derived from NIRS.Probe positions observing dominant changes of oxygenated hemoglobin and deoxyHb were displaced slightly, indicating the variety of vascularity. Since NIRS results by a single probe suffer from spatial ambiguity of measurements, it is sometimes hard to derive a hemodynamic model. Improvement of spatial resolution in NIRS is necessary for further investigation of brain hemodynamics in response to neuronal activation.

本研究的目的是通过同时测量功能磁共振成像(FMRI)和近红外光谱(NIRS)来了解神经元激活时的脑血流动力学。首先，为了更好地检测反映血流动力学变化的区域，分析了fMRI中的伪影。其次，将MRS探头植入MRI孔中，同时测量手指敲击任务中的MRI和NIR。根据两种不同技术的观测结果，对脑血流动力学进行了解释。(1)引入了一种新的基于热噪声强度的fMRI伪影分析方法，用于定量评估对抗伪影的效果。研究表明，与任务相关的运动和呼吸的主要影响都是头部整体运动，可以通过运动校正软件(SPM)进行校正，它们都具有伪影像素的时间强度变化特性。真实地减少脉动的影响是无伪影磁共振成像的关键。对8 PM运动矫正的效果也进行了定量评估。一个依赖于图像空间分辨率的陷阱被揭示出来。FMRI和NIRS的同时测量表明，反映fMRI BOLD类型变化的区域可以用NIR产生的脱氧血红蛋白(DeoxHb)的变化来解释。观察到氧合Hb和脱氧Hb的优势变化的可能位置略有移位，表明血管的变化。由于单探头的近红外光谱测量结果存在测量的空间模糊性，有时很难得到血流动力学模型。提高近红外光谱的空间分辨率是进一步研究脑血流动力学对神经元激活的反应所必需的。

项目成果

S.Kumazawa: "An optimized period of stimulation to improve quality of fMRI derived from quantitative noise analysis" Proc.Int.Soc.Magn.Reson.Med.,Sixth Annual Meeting. 1460 (1998)

S.Kumazawa：“优化刺激周期以提高源自定量噪声分析的 fMRI 质量”Proc.Int.Soc.Magn.Reson.Med.，第六届年会。

S.Kumazawa: "Evaluation of motion correction in fMRI-dependency of spatial resolution-" Proc.Int.Soc.Magn.Reson.Med., Seventh Annual Meeting. 1675 (1999)

S.Kumazawa：“功能磁共振成像运动校正的评估-空间分辨率的依赖性”Proc.Int.Soc.Magn.Reson.Med.，第七届年会。

S.Kumazawa: "Evaluation of motion correction in fMRI-dependency of spatial resolution-" Proc.Int.Soc.Magn.Reson.Med.,Seventh Annual Meeting. 1675 (1999)

S.Kumazawa：“功能磁共振成像运动校正的评估-空间分辨率的依赖性”Proc.Int.Soc.Magn.Reson.Med.，第七届年会。

S.Kumazawa: "An optimized period of stimulation to improve quality of fMRI derived from quantitative noise analysis" Proc.Int.Soc.Magn.Reson.Med.,Sixth Annual Meeting. (1998)

S.Kumazawa：“优化刺激周期以提高源自定量噪声分析的 fMRI 质量”Proc.Int.Soc.Magn.Reson.Med.，第六届年会。