Rose S E, McMahon K L, Janke A L, O'Dowd B, de Zubicaray G, Strudwick M W, Chalk J B
Centre for Magnetic Resonance, University of Queensland, Brisbane 4072, Australia.
J Neurol Neurosurg Psychiatry. 2006 Oct;77(10):1122-8. doi: 10.1136/jnnp.2005.074336. Epub 2006 Jun 5.
Magnetic resonance diffusion tensor imaging (DTI) shows promise in the early detection of microstructural pathophysiological changes in the brain.
To measure microstructural differences in the brains of participants with amnestic mild cognitive impairment (MCI) compared with an age-matched control group using an optimised DTI technique with fully automated image analysis tools and to investigate the correlation between diffusivity measurements and neuropsychological performance scores across groups.
34 participants (17 participants with MCI, 17 healthy elderly adults) underwent magnetic resonance imaging (MRI)-based DTI. To control for the effects of anatomical variation, diffusion images of all participants were registered to standard anatomical space. Significant statistical differences in diffusivity measurements between the two groups were determined on a pixel-by-pixel basis using gaussian random field theory.
Significantly raised mean diffusivity measurements (p<0.001) were observed in the left and right entorhinal cortices (BA28), posterior occipital-parietal cortex (BA18 and BA19), right parietal supramarginal gyrus (BA40) and right frontal precentral gyri (BA4 and BA6) in participants with MCI. With respect to fractional anisotropy, participants with MCI had significantly reduced measurements (p<0.001) in the limbic parahippocampal subgyral white matter, right thalamus and left posterior cingulate. Pearson's correlation coefficients calculated across all participants showed significant correlations between neuropsychological assessment scores and regional measurements of mean diffusivity and fractional anisotropy.
DTI-based diffusivity measures may offer a sensitive method of detecting subtle microstructural brain changes associated with preclinical Alzheimer's disease.
磁共振扩散张量成像（DTI）在早期检测大脑微观结构病理生理变化方面显示出前景。
使用具有全自动图像分析工具的优化DTI技术，测量遗忘型轻度认知障碍（MCI）参与者与年龄匹配的对照组大脑中的微观结构差异，并研究各组间扩散率测量值与神经心理学表现评分之间的相关性。
34名参与者（17名MCI参与者，17名健康老年人）接受了基于磁共振成像（MRI）的DTI检查。为了控制解剖变异的影响，将所有参与者的扩散图像配准到标准解剖空间。使用高斯随机场理论逐像素确定两组之间扩散率测量值的显著统计差异。
在MCI参与者的左右内嗅皮质（BA28）、枕后顶叶皮质（BA18和BA19）、右侧顶叶缘上回（BA40）和右侧额中央前回（BA4和BA6）中观察到平均扩散率测量值显著升高（p<0.001）。关于分数各向异性，MCI参与者在边缘海马旁回下白质、右侧丘脑和左侧后扣带回中的测量值显著降低（p<0.001）。对所有参与者计算的皮尔逊相关系数显示，神经心理学评估评分与平均扩散率和分数各向异性的区域测量值之间存在显著相关性。
基于DTI的扩散率测量可能提供一种检测与临床前阿尔茨海默病相关的细微脑微观结构变化的敏感方法。
