Stadlbauer Andreas, Ganslandt Oliver, Buslei Rolf, Hammen Thilo, Gruber Stephan, Moser Ewald, Buchfelder Michael, Salomonowitz Erich, Nimsky Christopher
Department of Neurosurgery, Neurocenter, Departments of Neuropathology and Neurology, University of Erlangen-Nuremberg, Erlangen, Germany.
Radiology. 2006 Sep;240(3):803-10. doi: 10.1148/radiol.2403050937.
To retrospectively correlate changes in fractional anisotropy (FA) and mean diffusivity in gliomas at diffusion-tensor magnetic resonance (MR) imaging with the degree of tumor cell infiltration determined histologically.
The institutional review board required neither ethics committee approval nor patient informed consent for this study. Twenty patients (eight women, 12 men; age range, 18-53 years) with glioma (seven World Health Organization grade II and 13 grade III tumors) underwent diffusion-tensor MR imaging at 1.5 T. Diffusion-tensor data were obtained with an echo-planar imaging sequence with six diffusion directions (b = 1000 sec/mm(2)), isotropic 1.9-mm voxels, and five averages. FA and mean diffusivity values were calculated from diffusion-tensor data. Coregistration with a three-dimensional MR imaging data set (used for stereotactic brain biopsies) enabled correlation of FA and mean diffusivity values with the histopathologic findings total cell number (CN), tumor CN, and percentage tumor infiltration (TI) by using linear, exponential, and logarithmic models. Student t and Mann-Whitney U tests were performed.
Histopathologic findings of 77 MR image-guided stereotactic biopsies in all 20 patients were correlated with FA and mean diffusivity values at the biopsy locus. For FA and mean diffusivity, a logarithmic model showed strongest correlation with tumor CN and total CN; a linear model showed strongest correlation with percentage TI. For FA there were negative logarithmic (R = -0.802, P < .001) and linear (R = -0.796, P < .001) correlations with tumor CN and percentage TI, respectively. For mean diffusivity there were positive logarithmic (R = 0.557, P < .001) and linear correlations (R = 0.521, P < .001) with tumor CN and percentage TI, respectively. Differences between correlations for FA and mean diffusivity versus tumor CN (P < .001) and percentage TI (P < .001) were significant.
FA is better than mean diffusivity for assessment and delineation of different degrees of pathologic changes (ie, TI) in glioma.
回顾性地将扩散张量磁共振成像（MR）中胶质瘤的分数各向异性（FA）和平均扩散率的变化与组织学确定的肿瘤细胞浸润程度相关联。
本研究无需机构审查委员会批准或患者知情同意。20例胶质瘤患者（8名女性，12名男性；年龄范围18 - 53岁）（7例世界卫生组织二级肿瘤和13例三级肿瘤）接受了1.5 T的扩散张量MR成像检查。使用具有六个扩散方向（b = 1000秒/毫米²）、各向同性1.9毫米体素和五次平均的回波平面成像序列获取扩散张量数据。从扩散张量数据计算FA和平均扩散率值。与三维MR成像数据集（用于立体定向脑活检）进行配准，通过线性、指数和对数模型将FA和平均扩散率值与组织病理学结果总细胞数（CN）、肿瘤CN和肿瘤浸润百分比（TI）相关联。进行了学生t检验和曼 - 惠特尼U检验。
对所有20例患者的77次MR图像引导的立体定向活检的组织病理学结果与活检部位的FA和平均扩散率值相关联。对于FA和平均扩散率，对数模型显示与肿瘤CN和总CN的相关性最强；线性模型显示与TI百分比的相关性最强。对于FA，与肿瘤CN和TI百分比分别存在负对数相关性（R = -0.802，P <.001）和线性相关性（R = -0.796，P <.001）。对于平均扩散率，与肿瘤CN和TI百分比分别存在正对数相关性（R = 0.557，P <.001）和线性相关性（R = 0.521，P <.001）。FA和平均扩散率与肿瘤CN（P <.001）和TI百分比（P <.001）之间的相关性差异具有显著性。
在评估和描绘胶质瘤不同程度的病理变化（即TI）方面，FA比平均扩散率更具优势。
