Jefferson Angela L, Gifford Katherine A, Damon Stephen, Chapman G William, Liu Dandan, Sparling Jamie, Dobromyslin Vitaly, Salat David
Vanderbilt Memory & Alzheimer's Center, Department of Neurology, Vanderbilt University Medical Center, 2525 West End Avenue, 12th Floor - Suite 1200, Nashville, TN, 37203, USA,
Brain Imaging Behav. 2015 Jun;9(2):141-8. doi: 10.1007/s11682-014-9291-2.
The clinical relevance of gray/white matter contrast ratio (GWR) in mild cognitive impairment (MCI) remains unknown. This study examined baseline GWR and 3-year follow-up diagnostic status in MCI. Alzheimer's Disease Neuroimaging Initiative MCI participants with baseline 1.5 T MRI and 3-year follow-up clinical data were included. Participants were categorized into two groups based on 3-year follow-up diagnoses: 1) non-converters (n = 69, 75 ± 7, 26 % female), and 2) converters (i.e., dementia at follow-up; n = 69, 75 ± 7, 30 % female) who were matched on baseline age and Mini-Mental State Examination scores. Groups were compared on FreeSurfer generated baseline GWR from structural images in which higher values represent greater tissue contrast. A general linear model, adjusting for APOE-status, scanner type, hippocampal volume, and cortical thickness, revealed that converters evidenced lower GWR values than non-converters (i.e., more degradation in tissue contrast; p = 0.03). Individuals with MCI who convert to dementia have lower baseline GWR values than individuals who remain diagnostically stable over a 3-year period, statistically independent of cortical thickness or hippocampal volume.
灰质/白质对比度（GWR）在轻度认知障碍（MCI）中的临床相关性尚不清楚。本研究调查了MCI患者的基线GWR和3年随访诊断状态。纳入了阿尔茨海默病神经影像学计划中具有基线1.5T磁共振成像（MRI）和3年随访临床数据的MCI参与者。根据3年随访诊断将参与者分为两组：1）未转化者（n = 69，75±7岁，26%为女性），以及2）转化者（即随访时患痴呆症；n = 69，75±7岁，30%为女性），两组在基线年龄和简易精神状态检查表得分上相匹配。比较两组基于FreeSurfer从结构图像生成的基线GWR，其中较高的值代表更大的组织对比度。一个校正了载脂蛋白E状态、扫描仪类型、海马体积和皮质厚度的一般线性模型显示，转化者的GWR值低于未转化者（即组织对比度下降更多；p = 0.03）。在3年期间转化为痴呆症的MCI个体，其基线GWR值低于诊断保持稳定的个体，在统计学上与皮质厚度或海马体积无关。
