Diagnostic Imaging and Radiotherapy Programme, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia.
Department of Imaging Technology & Sonography, School of Allied Health Sciences, University of Cape Coast, Cape Coast, Ghana.
PLoS One. 2021 Sep 21;16(9):e0252883. doi: 10.1371/journal.pone.0252883. eCollection 2021.
Alzheimer's disease (AD) is a major neurocognitive disorder identified by memory loss and a significant cognitive decline based on previous level of performance in one or more cognitive domains that interferes in the independence of everyday activities. The accuracy of imaging helps to identify the neuropathological features that differentiate AD from its common precursor, mild cognitive impairment (MCI). Identification of early signs will aid in risk stratification of disease and ensures proper management is instituted to reduce the morbidity and mortality associated with AD. Magnetic resonance imaging (MRI) using structural MRI (sMRI), functional MRI (fMRI), diffusion tensor imaging (DTI), and magnetic resonance spectroscopy (1H-MRS) performed alone is inadequate. Thus, the combination of multiparametric MRI is proposed to increase the accuracy of diagnosing MCI and AD when compared to elderly healthy controls.
This protocol describes a non-interventional case control study. The AD and MCI patients and the healthy elderly controls will undergo multi-parametric MRI. The protocol consists of sMRI, fMRI, DTI, and single-voxel proton MRS sequences. An eco-planar imaging (EPI) will be used to perform resting-state fMRI sequence. The structural images will be analysed using Computational Anatomy Toolbox-12, functional images will be analysed using Statistical Parametric Mapping-12, DPABI (Data Processing & Analysis for Brain Imaging), and Conn software, while DTI and 1H-MRS will be analysed using the FSL (FMRIB's Software Library) and Tarquin respectively. Correlation of the MRI results and the data acquired from the APOE genotyping, neuropsychological evaluations (i.e. Montreal Cognitive Assessment [MoCA], and Mini-Mental State Examination [MMSE] scores) will be performed. The imaging results will also be correlated with the sociodemographic factors. The diagnosis of AD and MCI will be standardized and based on the DSM-5 criteria and the neuropsychological scores.
The combination of sMRI, fMRI, DTI, and MRS sequences can provide information on the anatomical and functional changes in the brain such as regional grey matter volume atrophy, impaired functional connectivity among brain regions, and decreased metabolite levels specifically at the posterior cingulate cortex/precuneus. The combination of multiparametric MRI sequences can be used to stratify the management of MCI and AD patients. Accurate imaging can decide on the frequency of follow-up at memory clinics and select classifiers for machine learning that may aid in the disease identification and prognostication. Reliable and consistent quantification, using standardised protocols, are crucial to establish an optimal diagnostic capability in the early detection of Alzheimer's disease.
阿尔茨海默病（AD）是一种主要的神经认知障碍，其特征为记忆丧失和认知能力显著下降，认知能力下降的程度基于先前在一个或多个认知领域的表现水平，认知能力下降会影响日常活动的独立性。影像学的准确性有助于识别区分 AD 与其常见前驱病症——轻度认知障碍（MCI）的神经病理学特征。识别早期迹象有助于对疾病进行风险分层，并确保实施适当的管理，以降低与 AD 相关的发病率和死亡率。单独使用结构磁共振成像（sMRI）、功能磁共振成像（fMRI）、弥散张量成像（DTI）和磁共振波谱（1H-MRS）的准确性不足。因此，建议将多参数 MRI 联合使用，以提高诊断 MCI 和 AD 的准确性，与老年健康对照组相比。
本方案描述了一项非介入性病例对照研究。AD 和 MCI 患者以及健康的老年对照组将接受多参数 MRI 检查。方案包括 sMRI、fMRI、DTI 和单体质子 MRS 序列。生态平面成像（EPI）将用于执行静息状态 fMRI 序列。结构图像将使用计算解剖工具箱-12（Computational Anatomy Toolbox-12）进行分析，功能图像将使用统计参数映射-12（Statistical Parametric Mapping-12）、DPABI（用于脑成像的数据处理和分析）和 Conn 软件进行分析，而 DTI 和 1H-MRS 将分别使用 FSL（脑成像软件库）和 Tarquin 进行分析。将对 MRI 结果与 APOE 基因分型、神经心理学评估（即蒙特利尔认知评估 [MoCA] 和简易精神状态检查 [MMSE] 评分）获得的数据进行相关性分析。将还将对成像结果与社会人口因素进行相关性分析。AD 和 MCI 的诊断将根据 DSM-5 标准和神经心理学评分进行标准化。
sMRI、fMRI、DTI 和 MRS 序列的组合可以提供有关大脑解剖和功能变化的信息，例如区域性灰质体积萎缩、脑区之间功能连接受损以及后扣带回皮层/楔前叶特定部位代谢物水平降低。多参数 MRI 序列的组合可用于对 MCI 和 AD 患者进行分层管理。准确的影像学检查可以决定在记忆诊所进行随访的频率，并选择用于机器学习的分类器，这可能有助于识别和预测疾病。使用标准化方案进行可靠和一致的量化对于在早期检测阿尔茨海默病时建立最佳诊断能力至关重要。
