Levendovszky Swati Rane, Flores Jaqueline, Peskind Elaine R, Václavů Lena, van Osch Matthias J P, Iliff Jeffrey
Department of Radiology, University of Washington School of Medicine, 1959 NE Pacific Street, Seattle, WA 98195.
Mental Illness Research, Education, and Clinical Center, Veterans Affairs Puget Sound Systems, 1660 S Columbian Way, Seattle, WA 98108.
bioRxiv. 2023 Aug 29:2023.08.28.555150. doi: 10.1101/2023.08.28.555150.
We discuss two potential non-invasive MRI methods to cross-sectionally study two distinct facets of the glymphatic system and its association with sleep and aging. We apply diffusion-based intravoxel incoherent motion (IVIM) imaging to evaluate pseudodiffusion coefficient, , or cerebrospinal fluid (CSF) movement across large spaces like the subarachnoid space (SAS). We also performed perfusion-based multi-echo, Hadamard encoded multi-delay arterial spin labeling (ASL) to evaluate whole brain cortical cerebral blood flow (CBF) and transendothelial exchange (T) of water from the vasculature into the perivascular space and parenchyma. Both methods were used in young adults (N=9, 6F, 23±3 years old) in the setting of sleep and sleep deprivation. To study aging, 10 older adults, (6F, 67±3 years old) were imaged after a night of normal sleep only and compared with the young adults. in SAS was significantly (p<0.05) lesser after sleep deprivation (0.014±0.001 mm/s) than after normal sleep (0.016±0.001 mm/s), but was unchanged with aging. Cortical CBF and T on the other hand, were unchanged after sleep deprivation but were significantly lower in older adults (37±3 ml/100g/min, 476±66 ms) than young adults (42±2 ml/100g/min, 624±66 ms). IVIM was thus, sensitive to sleep physiology and multi-echo, multi-delay ASL was sensitive to aging.
我们讨论了两种潜在的非侵入性磁共振成像（MRI）方法，用于横断面研究淋巴系统的两个不同方面及其与睡眠和衰老的关系。我们应用基于扩散的体素内不相干运动（IVIM）成像来评估伪扩散系数，即脑脊液（CSF）在蛛网膜下腔（SAS）等大空间中的移动情况。我们还进行了基于灌注的多回波、哈达玛编码多延迟动脉自旋标记（ASL），以评估全脑皮质脑血流量（CBF）以及水从血管系统进入血管周围间隙和实质的跨内皮交换（T）。这两种方法均用于年轻成年人（N = 9，6名女性，23±3岁）的睡眠和睡眠剥夺研究。为了研究衰老，对10名老年人（6名女性，67±3岁）仅在正常睡眠一晚后进行成像，并与年轻成年人进行比较。睡眠剥夺后（0.014±0.001 mm/s），SAS中的 显著低于正常睡眠后（0.016±0.001 mm/s）（p<0.05），但衰老过程中无变化。另一方面，睡眠剥夺后皮质CBF和T无变化，但老年人（37±3 ml/100g/min，476±66 ms）显著低于年轻成年人（42±2 ml/100g/min，624±66 ms）。因此，IVIM对睡眠生理敏感，多回波、多延迟ASL对衰老敏感。
