Chételat G, Landeau B, Eustache F, Mézenge F, Viader F, de la Sayette V, Desgranges B, Baron J-C
Inserm E0218-Université de Caen, Laboratoire de Neuropsychologie, Centre Cyceron, Bd. H. Becquerel, BP 5229, 14074 Caen cedex, France.
Neuroimage. 2005 Oct 1;27(4):934-46. doi: 10.1016/j.neuroimage.2005.05.015.
Capturing the dynamics of gray matter (GM) atrophy in relation to the conversion from mild cognitive impairment (MCI) to clinically probable Alzheimer's disease (AD) would be of considerable interest. In this prospective study we have used a novel longitudinal voxel-based method to map the progression of GM loss in MCI patients over time and compared converters to non-converters. Eighteen amnestic MCI patients were followed-up for a predefined fixed period of 18 months and conversion was judged according to NINCDS-ADRDA criteria for probable AD. Each patient underwent a high-resolution T1-weighted volume MRI scan both at entry in the study and 18 months later. We used an optimal VBM protocol to compare baseline imaging data of converters to those of non-converters. Moreover, to map GM loss from baseline to follow-up assessment, we used a modified voxel-based morphometry (VBM) procedure specially designed for longitudinal studies. At the end of the follow-up period, seven patients had converted to probable AD. Areas of lower baseline GM value in converters mainly included the hippocampus, parahippocampal cortex, and lingual and fusiform gyri. Regions of significant GM loss over the 18-month follow-up period common to both converters and non-converters included the temporal neocortex, parahippocampal cortex, orbitofrontal and inferior parietal areas, and the left thalamus. However, there was significantly greater GM loss in converters relative to non-converters in the hippocampal area, inferior and middle temporal gyrus, posterior cingulate, and precuneus. This accelerated atrophy may result from both neurofibrillary tangles accumulation and parallel pathological processes such as functional alteration in the posterior cingulate. The ability to longitudinally assess GM changes in MCI offers new perspectives to better understand the pathological processes underlying AD and to monitor the effects of treatment on brain structure.
了解与从轻度认知障碍（MCI）转变为临床可能的阿尔茨海默病（AD）相关的灰质（GM）萎缩动态变化将具有重大意义。在这项前瞻性研究中，我们使用了一种新颖的基于体素的纵向方法来描绘MCI患者GM损失随时间的进展情况，并将转化者与未转化者进行比较。18名遗忘型MCI患者被随访了预定的18个月固定期，并根据NINCDS-ADRDA标准对可能的AD进行转化判断。每位患者在研究开始时和18个月后均接受了高分辨率T1加权容积MRI扫描。我们使用最佳的体素形态学测量（VBM）方案来比较转化者与未转化者的基线成像数据。此外，为了描绘从基线到随访评估的GM损失情况，我们使用了专门为纵向研究设计的改良基于体素的形态学测量（VBM）程序。在随访期结束时，7名患者已转化为可能的AD。转化者中基线GM值较低的区域主要包括海马体、海马旁皮质以及舌回和梭状回。在18个月的随访期内，转化者和未转化者共同出现显著GM损失的区域包括颞叶新皮质、海马旁皮质、眶额和顶下区域以及左侧丘脑。然而，与未转化者相比，转化者在海马区、颞下回和颞中回、后扣带回和楔前叶的GM损失明显更大。这种加速萎缩可能是由神经原纤维缠结的积累以及平行的病理过程（如后扣带回的功能改变）共同导致的。纵向评估MCI中GM变化的能力为更好地理解AD潜在的病理过程以及监测治疗对脑结构的影响提供了新的视角。
