Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA.
Department of Neurology, Emory University, Atlanta, GA.
J Neuroimaging. 2019 Jan;29(1):79-84. doi: 10.1111/jon.12588. Epub 2018 Dec 11.
Mild cognitive impairment (MCI) is a prevalent disorder, with a subset of patients progressing to dementia each year. Although MCI may be subdivided into amnestic or vascular types as well as into single or multiple cognitive domain involvement, most prior studies using advanced diffusion imaging have not accounted for these categories. The purpose of the current study was to determine if the pattern of diffusion tensor imaging (DTI) and diffusion kurtosis imaging (DKI) metrics in patients with amnestic MCI (aMCI) correlate to specific cognitive domain impairments.
Nineteen consecutive patients with aMCI referred for brain magnetic resonance imaging (MRI) were included. All subjects underwent neurocognitive testing. A z-score was calculated for each domain and a composite of all four domains. Brain MRI included standard structural imaging and diffusion imaging. Volumetric, DTI, and DKI metrics were calculated and statistical analysis was performed with adjustments for multiple measures and comparisons.
Statistically significant correlations between diffusion metrics and cognitive z-scores were detected: visuospatial-visuoconstructional z-scores only correlated with alterations in the corpus callosum splenium, executive functioning z-scores with the corpus callosum genu, memory testing z-scores with the left hippocampus, and composite z-scores with the anterior centrum semiovale.
Neuroimaging studies of patients with aMCI to date have assumed a population with homogeneous cognitive impairment. Our results demonstrate selective patterns of regional diffusion metric alterations correlate to specific cognitive domain impairments. Future studies should account for this heterogeneity, and this may also be useful for prognostication.
轻度认知障碍（MCI）是一种常见疾病，每年有一部分患者会进展为痴呆。虽然 MCI 可以分为遗忘型或血管型，以及单一或多个认知域受累，但大多数先前使用高级扩散成像的研究并未考虑到这些类别。本研究的目的是确定遗忘型轻度认知障碍（aMCI）患者的扩散张量成像（DTI）和扩散峰度成像（DKI）指标模式是否与特定认知域损伤相关。
纳入了 19 例连续就诊的 aMCI 患者。所有患者均接受神经认知测试。为每个域和所有四个域的组合计算 z 分数。脑部 MRI 包括标准结构成像和扩散成像。计算容积、DTI 和 DKI 指标，并进行统计学分析，对多个测量值和比较进行调整。
在弥散指标和认知 z 分数之间检测到统计学显著相关性：仅视空间-视空间构建 z 分数与胼胝体压部的改变相关，执行功能 z 分数与胼胝体膝部相关，记忆测试 z 分数与左侧海马体相关，综合 z 分数与前正中半卵圆中心相关。
迄今为止，对 aMCI 患者的神经影像学研究假设了一个具有同质认知障碍的人群。我们的结果表明，区域性弥散指标改变的特定模式与特定认知域损伤相关。未来的研究应考虑到这种异质性，这对于预后也可能是有用的。
