Upgrading our view of Growing Older: Mapping Brain Changes across the Lifespan with Ultra High Field Multi-Spectral MRI

升级我们对变老的看法：利用超高场多光谱 MRI 绘制整个生命周期中的大脑变化图

• 批准号: BB/X018954/1
• 负责人: Mara Cercignani
• 金额: $ 109.58万
• 依托单位: CARDIFF UNIVERSITY
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FX018954%2F1
• 关键词: Upgrading; our; view; Growing; Older

The initial data transmitted from the James Webb Space Telescope have recently dramatically reminded the world that scientific understanding can be transformed by the improvement of image spatial resolution. Since the invention of magnetic resonance imaging (MRI) in 1973, similar breakthroughs in its spatial and temporal resolution have been key to its use in discovery science. Until we have access to the fine details of any process, we have no idea of the level of granularity that will be required in its modelling to provide satisfactory explanations and testable predictions.It has recently been recognized that the human brain's axons continue to become myelinated after birth and into adulthood; that this myelination is largely driven in a bootstrapping process by each neuron's experience; that the pattern of myelination in each cortical area defines the most important microcircuits in that area, where horizontal myelinated fibres are likely to carry inhibitory signals; and that brain MRI contrast is conveniently almost entirely dependent on the amount of myelin within each image voxel. In consequence, the generation of in-vivo MR brain images with a spatial resolution sufficient to distinguish and quantify myeloarchitecture has become a uniquely important goal in the study of human brain function. General population-wide trends in myelogenesis during development, and individual differences, may become key explanatory observations for cognitive psychology and the basis of empirical biomarkers in psychiatric disorders. At the same time, we have started to understand that the mechanisms of brain energy supply and consumption vary with age, and they may be closely related with changes in synaptogenesis and myelination across the lifespan.The attainable resolution in MRI depends on three main factors: the strength of the applied magnetic field, the efficiency of the radiofrequency receiver coil and its electronics, and the ingenuity of the sequences of RF and gradient field pulses employed in capturing the magnetic resonance signal. Currently the highest MRI field strength for which the engineering requirements are tractable is 7 Tesla, introduced for human-size scanners in about 2000, and the number of such scanners installed globally is approaching 100. Like many other medical technologies, MRI continues to undergo rapid development driven by Moore's Law, optoelectronics, maturing hardware design techniques, and strong market competition. Thus the first generation of 7T scanners, including the pioneering Siemens Magnetom scanner installed at CUBRIC in 2015, is now technologically far behind more recently marketed systems, such as the Siemens Terra scanner and the new GE 7T Signa. While the CUBRIC 7T scanner continues to outperform comparable 3T scanners in many respects, its ancillary hardware, computer equipment, and software environment leave it unable to deliver the feasible goal of acquiring isotropic 0.5 mm resolution images of brain quantitative microstructure and functional activity. This makes it unsuitable for cutting-edge studies (for example) of cortical changes in adult subjects learning new skills, of myeloarchitectural abnormalities in the brains of schoolchildren with behavioural problems, and of the sequence of cortical area maturation in the development of new visual skills, and to relate all of these changes to the changes in brain metabolism and the maintenance of healthy perfusion with age. The proposed upgrade will enable CUBRIC to investigate how the brain develops and maintains healthy function across the lifespan, a crucial research question as the world population live longer than ever.

从詹姆斯·韦伯（James Webb）太空望远镜传输的最初数据最近大大提醒世界，科学理解可以通过改善图像空间分辨率来改变。自1973年发明磁共振成像（MRI）以来，其空间和时间分辨率的类似突破是其在发现科学中使用的关键。在我们访问任何过程的细节之前，我们都不了解其建模中需要的粒度水平，以提供令人满意的解释和可测试的预测。最近，人们已经认识到，人脑的轴突继续变得骨髓出生和成年后；每种神经元的经验都在引导过程中驱动了这种髓鞘。每个皮质区域中的髓鞘化模式定义了该区域中最重要的微电路，其中水平的髓载纤维可能携带抑制性信号。并且大脑MRI对比度几乎完全取决于每个图像体素内的髓磷脂量。因此，具有空间分辨率足以区分和量化骨髓结构的空间分辨率的体内MR脑图像的产生已成为研究人脑功能的独特目标。发育过程中骨髓生成和个体差异的一般人口范围的趋势可能成为认知心理学的关键解释性观察和精神疾病经验生物标志物的基础。同时，我们已经开始了解，大脑能量供应和消费的机制随着年龄的增长而有所不同，并且它们可能与整个寿命的突触发生和髓鞘变化密切相关。MRI的可实现分辨率取决于三个主要因素：施加的磁场的强度，射频接收器线圈及其电子设备的效率以及RF和梯度场脉冲序列的创造力，用于捕获磁共振信号。目前，工程要求可容纳的最高MRI野外强度是7特斯拉，在2000年左右为人类大小的扫描仪引入，全球安装的此类扫描仪的数量接近100。由摩尔定律，光电子，成熟的硬件设计技术和强大的市场竞争驱动的发展。因此，第一代7T扫描仪，包括2015年在Cubric安装的先锋磁铁扫描仪，现在在技术上远远落后于最近推销的系统，例如Siemens Terra扫描仪和新的GE 7T Signa。在许多方面，Cubric 7T扫描仪继续胜过可比较的3T扫描仪，但其辅助硬件，计算机设备和软件环境使其无法实现获得各向同性0.5 mm分辨率的大脑定量微结构和功能活动的可行目标。这使得成人受试者的皮质变化不适合学习新技能的皮质变化，具有行为问题的学童的骨髓结构异常，以及在新的视觉技能发展中的皮质区域成熟的顺序，并将所有这些变化与大脑代谢的变化以及随着年龄的增长的维持。拟议的升级将使Cubric能够研究大脑在整个生命周期中如何发展和保持健康功能，这是世界人口比以往任何时候都更长的关键研究问题。