Evaluation of peritumoral fiber structures of N-ethyl-N-nitrosourea-induced rat brain glioma using Diffusion tensor MR imaging : comparison between vector map and histology

通过对N-乙基-N-亚硝脲(ENU)诱导的大鼠脑胶质瘤的扩散张量磁共振(DT-MR)图像和神经丝(NF)免疫染色组织切片的比较，研究了ENU诱导的大鼠脑胶质瘤周围区纤维结构的变化。所有程序都通过了机构实验室动物保护和使用委员会的批准。实验是在一台7T/40厘米的水平磁体上进行的，该磁体配备了12厘米的梯度，最高可达400mT/m，连接到一个实验的核磁共振系统。将固定的脑置于充满0.1M磷酸盐缓冲液的试管中，进行体外DT-MR成像。采集参数为2000/36/12-14(TRmsec/TE msec/Average)，视野24 mm，层厚0.5 mm，扫描矩阵256×256(0.0938×0.0938×0.5 mm^3)。获得了6个不同非共线方向的扩散加权图像和T2加权图像的数据集，其b值=1027秒/mm^2。来自漫反射…生成了更多的张量数据、基于DT-MR成像的彩色地图和矢量地图。DT-MR成像后，用抗生物素-生物素-过氧化物酶复合物法进行神经丝免疫组织化学染色。我们通过与相应的神经丝(NF)免疫染色的组织切片进行比较，直观地评价了矢量图所描述的瘤周白质结构。(1)在正常脑白质中，矢量图可以在免疫组化切片上显示有序的矢状线，与有序的神经纤维结构相对应。(2)矢状图可清晰显示正常脑白质与肿瘤交界处的矢状线增宽和断裂，并经组织切片证实。(3)在T2加权像上，矢量图显示瘤周区排列整齐的矢状线，呈异常高信号，组织学显示瘤周正常排列整齐的核因子束，无肿瘤细胞。(4)向量图不能完全描述肿瘤内散在分布的残留的神经纤维束碎片。较少

We investigated fiber structures in the peripheral zone of N-ethyl-N-nitrosourea (ENU)-induced rat brain glioma by comparison between diffusion tensor MR (DT-MR) images and neurofilament (NF) immunostained histological sections.In this study, six Fisher-334 rats, which had been treated transplacentally with ENU, underwent in vitro MR imaging. All procedures met institutional Laboratory Animal Care and Use Committee approval. The experiments were performed on a horizontal 7T/40 cm magnet equipped with a 12cm gradient set up to 400mT/m interfaced to an experimental NMR system. The fixed brain was put into the tube filled with 0.1M phosphate buffer for in vitro DT-MR imaging. Acquisition parameters were 2000/36/12-14 (TR msec/TE msec/averaging), 24mm field of view, 0.5mm slice thickness, 256x256 scan matrix (0.0938x0.0938x0.5mm^3). A data set of diffusion-weighted images with b-value=1027sec/mm^2 in six different noncolinear directions and T2-weighted images was obtained. From the diffusi … More on-tensor data, DT-MR imaging-based color maps and vector maps were generated. After DT-MR imaging, neurofilament immunohistochemistry was performed using the avidin-biotin-peroxidase complex method. We visually evaluated peritomoral white matter architecture described by the vector maps in comparison with corresponding neurofilament (NF) immunostained histological sections.We obtained the following results. (1)In normal white matter, the vector map could depict well-ordered vector bars corresponding ordered NF structures in immunostained histological sections. (2)The vector map could clearly show peritumoral widening and disruption of the vector bars along the border between normal white matter and tumor, which were confirmed by the histological sections. (3)The vector maps showed well-ordered vector bars in the peritumoral area with abnormal hyper intensity on T2-weighted images, where histology revealed normal well-ordered NF bundles without tumor cells in the area. (4)The vector map could not fully describe scattered residual NF bundle pieces in the tumor. Less