Defrancesco Michaela, Egger Karl, Marksteiner Josef, Esterhammer Regina, Hinterhuber Hartmann, Deisenhammer Eberhard A, Schocke Michael
Department of General Psychiatry, Innsbruck Medical University, Innsbruck, Austria.
Department of Neuroradiology, University Clinic Freiburg, Freiburg, Germany.
PLoS One. 2014 Aug 25;9(8):e106062. doi: 10.1371/journal.pone.0106062. eCollection 2014.
Mild cognitive impairment (MCI) may represent an early stage of dementia conferring a particularly high annual risk of 15-20% of conversion to Alzheimer's disease (AD). Recent findings suggest that not only gray matter (GM) loss but also a decline in white matter (WM) integrity may be associated with imminent conversion from MCI to AD.
In this study we used Voxel-based morphometry (VBM) to examine if gray matter loss and/or an increase of the apparent diffusion coefficient (ADC) reflecting mean diffusivity (MD) are an early marker of conversion from MCI to AD in a high risk population.
Retrospective neuropsychological and clinical data were collected for fifty-five subjects (MCI converters n = 13, MCI non-converters n = 14, healthy controls n = 28) at baseline and one follow-up visit. All participants underwent diffusion weighted imaging (DWI) and T1-weighted structural magnetic resonance imaging scans at baseline to analyse changes in GM density and WM integrity using VBM.
At baseline MCI converters showed impaired performance in verbal memory and naming compared to MCI non-converters. Further, MCI converters showed decreased WM integrity in the frontal, parietal, occipital, as well as the temporal lobe prior to conversion to AD. Multiple regression analysis showed a positive correlation of gray matter atrophy with specific neuropsychological test results.
Our results suggest that additionally to morphological changes of GM a reduced integrity of WM indicates an imminent progression from MCI stage to AD. Therefore, we suggest that DWI is useful in the early diagnosis of AD.
轻度认知障碍（MCI）可能是痴呆症的早期阶段，每年转化为阿尔茨海默病（AD）的风险特别高，达15%-20%。最近的研究结果表明，不仅灰质（GM）损失，而且白质（WM）完整性下降可能与MCI即将转化为AD有关。
在本研究中，我们使用基于体素的形态测量法（VBM）来检查灰质损失和/或反映平均扩散率（MD）的表观扩散系数（ADC）增加是否是高危人群中MCI转化为AD的早期标志物。
回顾性收集了55名受试者（MCI转化者n = 13，MCI未转化者n = 14，健康对照者n = 28）在基线和一次随访时的神经心理学和临床数据。所有参与者在基线时均接受了扩散加权成像（DWI）和T1加权结构磁共振成像扫描，以使用VBM分析GM密度和WM完整性的变化。
在基线时，与MCI未转化者相比，MCI转化者在言语记忆和命名方面表现受损。此外，MCI转化者在转化为AD之前，额叶、顶叶、枕叶以及颞叶的WM完整性下降。多元回归分析显示灰质萎缩与特定神经心理学测试结果呈正相关。
我们的结果表明，除了GM的形态学变化外，WM完整性降低表明MCI阶段即将进展为AD。因此，我们建议DWI在AD的早期诊断中有用。
