Center for Advanced Technology and Education, Department of Electrical and Computer Engineering, Florida International University, Miami, FL, United States.
Center for Advanced Technology and Education, Department of Electrical and Computer Engineering, Florida International University, Miami, FL, United States.
J Neurosci Methods. 2019 Apr 1;317:121-140. doi: 10.1016/j.jneumeth.2018.12.012. Epub 2018 Dec 26.
Functional magnetic resonance imaging (fMRI) is an MRI-based neuroimaging technique that measures brain activity on the basis of blood oxygenation level. This study reviews the main fMRI methods reported in the literature and their related applications in clinical and preclinical studies, focusing on relating functional brain networks in the prodromal stages of Alzheimer's disease (AD), with a focus on the transition phases from cognitively normal (CN) to mild cognitive impairment (MCI) and from MCI to AD.
The purpose of this study is to present and compare different approaches of supervised and unsupervised fMRI analyses and to highlight the different applications of fMRI in the diagnosis of MCI and AD.
Survey article asserts that brain network disruptions of a given dysfunction or in relation to disease prone areas of the brain in neurodegenerative dementias could be extremely useful in ascertaining the extent of cognitive deficits at the different stages of the disease. Identifying the earliest changes in these activity patterns is essential for the early planning of treatment and therapeutic protocols.
Analysis methods such as independent component analysis (ICA) and graph theory-based approaches are strong analytical techniques most suitable for functional connectivity investigations. However, graph theory-based approaches have received more attention due to the higher performance they achieve in both functional and effective connectivity studies.
This article shows that the disruption of brain connectivity patterns of MCI and AD could be associated with cognitive decline, an interesting finding that could augment the prospects for early diagnosis. More importantly, results reveal that changes in functional connectivity as obtained through fMRI precede detection of cortical thinning in structural MRI and amyloid deposition in positron emission tomography (PET). However, a major challenge in using fMRI as a single imaging modality, like all other imaging modalities used in isolation, is in relating a particular disruption in functional connectivity in relation to a specific disease. This is a challenge that requires more thorough investigation, and one that could perhaps be overcome through multimodal neuroimaging by consolidating the strengths of these individual imaging modalities.
功能磁共振成像（fMRI）是一种基于 MRI 的神经影像学技术，它基于血氧水平来测量大脑活动。本研究综述了文献中报道的主要 fMRI 方法及其在临床前研究中的相关应用，重点关注阿尔茨海默病（AD）前驱期相关的功能性脑网络，重点关注从认知正常（CN）到轻度认知障碍（MCI）以及从 MCI 到 AD 的过渡阶段。
本研究旨在介绍和比较监督和无监督 fMRI 分析的不同方法，并强调 fMRI 在 MCI 和 AD 诊断中的不同应用。
综述文章断言，在神经退行性痴呆中，与大脑特定功能障碍或与大脑易患病区相关的脑网络中断，对于确定疾病不同阶段的认知缺陷程度非常有用。确定这些活动模式的最早变化对于早期规划治疗和治疗方案至关重要。
独立成分分析（ICA）和基于图论的方法等分析方法是非常适合功能连接研究的强大分析技术。然而，由于它们在功能和有效连接研究中表现出更高的性能，基于图论的方法受到了更多的关注。
本文表明，MCI 和 AD 的脑连接模式中断可能与认知能力下降有关，这一有趣的发现可能会增加早期诊断的前景。更重要的是，结果表明，通过 fMRI 获得的功能连接变化早于结构 MRI 中皮质变薄和正电子发射断层扫描（PET）中淀粉样蛋白沉积的检测。然而，将 fMRI 作为单一成像方式使用的主要挑战，就像所有单独使用的成像方式一样，是在于将特定的功能连接中断与特定的疾病联系起来。这是一个需要更深入研究的挑战，通过整合这些单独成像方式的优势，通过多模态神经影像学或许可以克服这一挑战。
