Brain Imaging and Analysis Center, Duke University Medical Center, Box 3918, Durham, NC 27710, USA; Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA; Center for Cognitive Neuroscience, Duke University, Durham, NC 27708, USA.
Brain Imaging and Analysis Center, Duke University Medical Center, Box 3918, Durham, NC 27710, USA.
Neuroimage. 2023 Nov 15;282:120401. doi: 10.1016/j.neuroimage.2023.120401. Epub 2023 Oct 5.
Quantitative susceptibility mapping (QSM) is a magnetic resonance imaging (MRI) technique that can assess the magnetic properties of cerebral iron in vivo. Although brain iron is necessary for basic neurobiological functions, excess iron content disrupts homeostasis, leads to oxidative stress, and ultimately contributes to neurodegenerative disease. However, some degree of elevated brain iron is present even among healthy older adults. To better understand the topographical pattern of iron accumulation and its relation to cognitive aging, we conducted an integrative review of 47 QSM studies of healthy aging, with a focus on five distinct themes. The first two themes focused on age-related increases in iron accumulation in deep gray matter nuclei versus the cortex. The overall level of iron is higher in deep gray matter nuclei than in cortical regions. Deep gray matter nuclei vary with regard to age-related effects, which are most prominent in the putamen, and age-related deposition of iron is also observed in frontal, temporal, and parietal cortical regions during healthy aging. The third theme focused on the behavioral relevance of iron content and indicated that higher iron in both deep gray matter and cortical regions was related to decline in fluid (speed-dependent) cognition. A handful of multimodal studies, reviewed in the fourth theme, suggest that iron interacts with imaging measures of brain function, white matter degradation, and the accumulation of neuropathologies. The final theme concerning modifiers of brain iron pointed to potential roles of cardiovascular, dietary, and genetic factors. Although QSM is a relatively recent tool for assessing cerebral iron accumulation, it has significant promise for contributing new insights into healthy neurocognitive aging.
定量磁化率映射（QSM）是一种磁共振成像（MRI）技术，可评估脑内铁的磁特性。尽管脑铁对于基本的神经生物学功能是必需的，但过量的铁含量会破坏体内平衡，导致氧化应激，最终导致神经退行性疾病。然而，即使在健康的老年人群中，也存在一定程度的脑铁升高。为了更好地了解铁积累的地形模式及其与认知老化的关系，我们对 47 项关于健康衰老的 QSM 研究进行了综合回顾，重点关注了五个不同的主题。前两个主题集中在与年龄相关的大脑深部灰质核中铁积累的增加与皮质相比。总的来说，深部灰质核中的铁含量高于皮质区域。深部灰质核在与年龄相关的影响方面存在差异，其中壳核最为明显，在健康衰老过程中，额叶、颞叶和顶叶皮质区域也观察到与年龄相关的铁沉积。第三个主题侧重于铁含量的行为相关性，并表明深部灰质核和皮质区域的铁含量越高，与流体（速度依赖性）认知能力下降有关。在第四个主题中回顾的少数几项多模态研究表明，铁与大脑功能、白质退化和神经病理学积累的影像学测量相互作用。最后一个主题涉及大脑铁的修饰物，指出心血管、饮食和遗传因素可能发挥作用。虽然 QSM 是评估脑内铁积累的相对较新的工具，但它在为健康神经认知老化提供新的见解方面具有很大的潜力。
