Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, Scientific Institute and University Ospedale San Raffaele, Milan, Italy.
J Alzheimers Dis. 2011;24(3):455-74. doi: 10.3233/JAD-2011-101854.
Patients with Alzheimer’s disease (AD) experience a brain network breakdown, reflecting disconnection at both the structural and functional system level. Resting-state (RS) functional MRI (fMRI) studies demonstrated that the regional coherence of the fMRI signal is significantly altered in patients with AD and amnestic mild cognitive impairment. Diffusion tensor (DT) MRI has made it possible to track fiber bundle projections across the brain, revealing a substantially abnormal interplay of “critical” white matter tracts in these conditions. The observed agreement between the results of RS fMRI and DT MRI tractography studies in healthy individuals is encouraging and offers interesting hypotheses to be tested in patients with AD, a MCI, and other dementias in order to improve our understanding of their pathobiology in vivo. In this review,we describe the major findings obtained in AD using RS fMRI and DT MRI tractography, and discuss how the relationship between structure and function of the brain networks in AD may be better understood through the application of MR-based technology. This research endeavor holds a great promise in clarifying the mechanisms of cognitive decline in complex chronic neurodegenerative disorders.
阿尔茨海默病（AD）患者的大脑网络会出现破裂，这反映了结构和功能系统层面的连接中断。静息态（RS）功能磁共振成像（fMRI）研究表明，AD 和遗忘型轻度认知障碍患者的 fMRI 信号的局部相干性显著改变。扩散张量（DT）MRI 使得在大脑中追踪纤维束投射成为可能，揭示了这些情况下“关键”白质束的实质性异常相互作用。在健康个体中，RS fMRI 和 DT MRI 轨迹追踪研究结果之间的观察到的一致性令人鼓舞，并为 AD、MCI 和其他痴呆症患者提供了有趣的假设，以帮助我们更好地了解其体内的病理生物学。在这篇综述中，我们描述了使用 RS fMRI 和 DT MRI 轨迹追踪在 AD 中获得的主要发现，并讨论了如何通过应用基于 MRI 的技术更好地理解 AD 中大脑网络的结构和功能关系。这项研究努力有望阐明复杂慢性神经退行性疾病中认知能力下降的机制。
