Analysis of mechanism for neuronal regeneration in damaged brain by using multi-modality MRI methods

我们开发了多模态磁共振成像（MRI）技术，用于分析受损大脑中的神经元再生。这些是;（1）利用超快速扩散加权成像获得的扩散张量图像的纤维追踪成像方法;（2）利用动态活性锰依赖对比MRI（DAIM MRI）的神经元激活成像方法。该方法基于神经元激活过程中Mn离子可与Ca离子共同进入神经元细胞的理论;（3）二维磁共振波谱（2D-MRS）可精确分析受损脑内各种代谢物;（4）动脉自旋标记法灌注成像;（4）超高场磁共振功能成像（fMRI）的改进。使用的MRI设备为实验用MRI机（4.7T Bruker Biospec和7.0T Varian INOVA 300 SWB）和人体全身MRI机（1.5T GE Signa Horizon、1.5T Siemens Symphony和3.0T GE Signa Horizon）。 ...更多信息 基于扩散张量方向的图像清楚地显示了纤维取向的三维分布。脑梗塞例出现纤维中断。在DAIM MRI中，大鼠嗅格罗夫、视神经和视放射线内的神经纤维清晰显示。该方法还能清晰显示皮质的六个层次。该方法可以直接根据神经元的激活情况来检测神经元的方向和大脑结构。2D-MRS、2D-JPRESS和2D-COSY在1.5T和3.0T临床MRI设备上开发。利用2D-MRS方法获得了常规MRS方法检测不到的脑代谢产物，如谷氨酰胺/谷氨酸、谷胱甘肽、苏氨酸和GABA。2D-MRS可从代谢角度检查受损脑的存活性。动脉自旋标记法灌注成像可无创性检测脑血流变化，结合弥散加权成像可了解脑梗死半影区的活性，多模态MR成像技术可无创性检测脑组织损伤后的再生和神经细胞功能。由于MRI方法在评价脑功能和代谢方面仍有较多的技术手段，有待于进一步研究。少

We have developed multi-modality magnetic resonance imaging (MRI) techniques for analysis of neuronal regeneration in damaged brain. Those are; (1)Fiber tracking imaging method by using diffusion tensor images obtained from ultra-fast diffusion weighted imaging; (2)Neuronal activation imaging method by using dynamic-activity manganese-dependent contrast MRI (DAIM MRI). This method depends on the theory that Mn ion can enter into neuronal cell in conjunction with Ca ion during the neuronal activation; (3)Two dimensional MR spectroscopy (2D-MRS) by which various brain metabolites can be analyzed precisely in damaged brain; (4)Perfusion imaging using arterial spin tagging method, (4)Improvement of functional MRI (fMRI) on ultra-high field magnet. MRI devices used were experimental MRI machines (4.7T Bruker Biospec and 7.0T Varian INOVA300SWB) and a whole body MRI machine for human (1.5T GE Signa Horizon,1.5T Siemens Symphony and 3.0T GE Signa Horizon).In fiber tracking imaging method, thr … More ee dimensional distribution of fiber orientation ~vas clearly demonstrated by the images based on diffusion tensor direction. Disconnection of fiber was demonstrated in cases of cerebral infarction. In DAIM MRI method, neuronal fibers were clearly demonstrated in rat olfactory grove, optic nerve and optic radiation. Also the six cortical layers were clearly demonstrated by this method. This method is useful to detect the neuronal orientation and brain structure directly based on the nerve cell activation. In 2D-MRS,2D-JPRESS and 2D-COSY were developed on 1.5T and 3.0T clinical MRI devices. Brain metabolites which could not be detected by conventional MRS method were obtained by those 2D-MRS method, such as glutamine/glutamate, glutathione, threonine and GABA. 2D-MRS is useful to examine the viability of damaged brain from the metabolic point of view. The perfusion imaging using arterial spin tagging method was useful to detect the cerebral blood flow change non-invasively, and the combination with diffusion weighted imaging is useful to know the viablity of penumbra region in cerebral infarction.In conclusion, the multi-modality MR methods are unique and useful to examine the regeneration of damaged brain tissue and nerve cell function non-invasively. Since there are still more techniques in MRI methods to evaluate the brain function and metabolism, further research should be continued. Less