Assessing arterial stiffness and cardiac pulsations in the brain at sub-millimetre resolution using MRI

使用 MRI 以亚毫米分辨率评估大脑中的动脉僵硬度和心脏搏动

• 批准号: 468695332
• 负责人: Joseph Whittaker, Ph.D.
• 金额: --
• 依托单位: Methoden- und Entwicklungsgruppe Magnetresonanztomographie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2022
• 资助国家: 德国
• 起止时间: 2021-12-31 至 无数据
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/468695332?language=en
• 关键词: Assessing; arterial; stiffness; cardiac; pulsations

The human brain requires a constant smooth flow of blood to maintain good neurological health. As the heart beats it causes blood to ‘pulsate’ through the large arteries, speeding up when the heart contracts, and slowing down when it relaxes. It is the elastic structure of the walls of large arteries that modify this pulsatile flow, and it is important as it protects the cerebral microcirculation from excessive pulsatile energy. However, as we age, changes occur in the structure of the artery wall that cause them to stiffen. As the brain is a high-flow organ, it is unsurprising that increased arterial stiffness is associated with cerebrovascular disease. For this reason, assessing the stiffness and pulsatility of arteries is highly clinically desirable, however there are currently very few methods to do this in the brain. In this project we propose to develop a novel ultra-high field magnetic resonance imaging (MRI) method for assessing both stiffness and pulsatility of cerebral arteries. Existing MRI methods ‘encode’ blood flow velocity into the MRI signal, but this requires additional magnetic fields to be generated by the scanner, which takes time. Our new approach is based on exploiting the strong sensitivity to blood flow velocity inherent in the MRI signal under certain conditions, and thus allows us to measure pulsatile flow in cerebral arteries with high temporal resolution.The proposed project includes an MRI sequence development theme and an applications theme. For the sequence development theme, we will develop a new method for assessing cerebral large arterial stiffness by measuring the speed of the cardiac pressure wave (i.e. pulse wave velocity). This measurement technique will provide a quantitative measure of stiffness in the internal carotid and middle cerebral artery segments. Then we will focus on measuring the pulsatility in the small lenticulostriate arteries that branch directly from the middle cerebral artery. These newly developed techniques will allow us to explore the relationship between the stiffness of large cerebral arteries and the associated pulsatility downstream in the small arteries. In the applications theme we will apply these new measurement techniques in a cohort of healthy individuals across a broad age range and in a cohort of patients with cerebral small vessel disease. This programme of experiments will allow us to characterise how cerebral large artery stiffness and downstream pulsatility evolve with age, and how this process is altered in patients with small vessel pathology.

人脑需要恒定的血液流动以维持良好的神经系统健康。当心脏跳动时，它会导致血液通过大动脉“脉动”，当心脏收缩时加速，并在放松时放慢脚步。它是大动脉壁的弹性结构来改变这种脉动流动，这很重要，因为它可以保护脑微循环免受过量的脉动能量。但是，随着年龄的增长，动脉壁的结构发生变化，导致它们变硬。由于大脑是高流量器官，因此增加动脉僵硬与脑血管疾病有关，这不足为奇。因此，评估动脉的刚度和脉动性在临床上是高度可取的，但是目前在大脑中很少有方法可以做到这一点。在这个项目中，我们建议开发一种新型的超高场磁共振成像（MRI）方法，用于现有的MRI方法将血流速度“编码”到MRI信号中，但这需要由扫描仪产生的其他磁场，这需要时间。我们的新方法是基于利用在某些条件下MRI信号固有的对血流速度的强烈敏感性，因此使我们能够测量具有高临时分辨率的脑动脉中的脉动流动。拟议项目包括MRI序列开发主题和应用主题。对于序列开发主题，我们将通过测量心脏压力波的速度（即脉冲波速度）来开发一种新方法来评估脑大动脉刚度。这种测量技术将对内部颈动脉和中部动脉段中的刚度进行定量测量。然后，我们将专注于测量直接从大脑中部动脉分支的小胸膜纤维结构动脉中的脉动性。这些新开发的技术将使我们能够探索大脑动脉的刚度与小动脉下游相关的脉动性之间的关系。在应用主题中，我们将在广泛的年龄范围内以及一系列脑小血管疾病的患者中应用这些新的测量技术。该实验计划将使我们能够表征大脑大动脉刚度和下游搏动性随着年龄的增长以及小血管病理患者的这种过程如何改变。