Wen Qiuting, Wright Adam, Tong Yunjie, Zhao Yi, Risacher Shannon L, Saykin Andrew J, Wu Yu-Chien, Limaye Kaustubh, Riley Kalen
Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, Indiana, USA.
Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, USA.
NMR Biomed. 2024 Feb;37(2):e5048. doi: 10.1002/nbm.5048. Epub 2023 Oct 5.
Paravascular cerebrospinal fluid (pCSF) surrounding the cerebral arteries within the glymphatic system is pulsatile and moves in synchrony with the pressure waves of the vessel wall. Whether such pulsatile pCSF can infer pulse wave propagation-a property tightly related to arterial stiffness-is unknown and has never been explored. Our recently developed imaging technique, dynamic diffusion-weighted imaging (dynDWI), captures the pulsatile pCSF dynamics in vivo and can explore this question. In this work, we evaluated the time shifts between pCSF waves and finger pulse waves, where pCSF waves were measured by dynDWI and finger pulse waves were measured by the scanner's built-in finger pulse oximeter. We hypothesized that the time shifts reflect brain-finger pulse wave travel time and are sensitive to arterial stiffness. We applied the framework to 36 participants aged 18-82 years to study the age effect of travel time, as well as its associations with cognitive function within the older participants (N = 15, age > 60 years). Our results revealed a strong and consistent correlation between pCSF pulse and finger pulse (mean CorrCoeff = 0.66), supporting arterial pulsation as a major driver for pCSF dynamics. The time delay between pCSF and finger pulses (TimeDelay) was significantly lower (i.e., faster pulse propagation) with advanced age (Pearson's r = -0.44, p = 0.007). Shorter TimeDelay was further associated with worse cognitive function in the older participants. Overall, our study demonstrated pCSF as a viable pathway for measuring intracranial pulses and encouraged future studies to investigate its relevance with cerebrovascular functions.
类淋巴系统中围绕脑动脉的血管周围脑脊液（pCSF）呈脉动性，并与血管壁的压力波同步移动。这种脉动性pCSF是否能够推断脉搏波传播（一种与动脉僵硬度密切相关的特性）尚不清楚，且从未被探究过。我们最近开发的成像技术，动态扩散加权成像（dynDWI），能够在体内捕捉脉动性pCSF的动态变化，并可以探究这个问题。在这项研究中，我们评估了pCSF波与手指脉搏波之间的时间延迟，其中pCSF波通过dynDWI测量，手指脉搏波通过扫描仪内置的手指脉搏血氧仪测量。我们假设这种时间延迟反映了脑-手指脉搏波的传播时间，并且对动脉僵硬度敏感。我们将该框架应用于36名年龄在18 - 82岁的参与者，以研究传播时间的年龄效应，以及其与老年参与者（N = 15，年龄> 60岁）认知功能的关联。我们的结果显示pCSF脉冲与手指脉冲之间存在强烈且一致的相关性（平均相关系数= 0.66），支持动脉搏动是pCSF动态变化的主要驱动因素。随着年龄增长，pCSF与手指脉冲之间的时间延迟（TimeDelay）显著降低（即脉搏传播更快）（Pearson相关系数r = -0.44，p = 0.007）。在老年参与者中，较短的TimeDelay进一步与较差的认知功能相关。总体而言，我们的研究表明pCSF是测量颅内脉搏的可行途径，并鼓励未来的研究探讨其与脑血管功能的相关性。
