Kiviniemi Vesa, Helakari Heta, Raitamaa Lauri, Huotari Niko, Rajna Zalan, Järvelä Matti, Elabasy Ahmed, Tuunanen Johanna, Poltojainen Valter, Väyrynen Tommi, Tuovinen Timo, Kananen Janne, Korhonen Vesa
Oulu Functional NeuroImaging, HST/Oulu University, Oulu, Finland.
Diagnostics/MRC, Oulu University Hospital, Oulu, Finland.
NMR Biomed. 2025 Aug;38(8):e70092. doi: 10.1002/nbm.70092.
Over the past decade, novel in vivo imaging techniques have revealed that physiological pulsations drive the transport of brain solutes and that impairment of fluid flow precedes certain neuropathologies. Although the pioneering investigations on brain solute transport mechanisms mainly employed imaging of exogenous tracers, novel advanced ultrafast functional MRI sequences enable critical sampling of propagating physiological pulsations driving the brain fluids devoid of aliased mixing of signals. In this review, we summarize the emerging magnetic resonance encephalography (MREG) technique, beginning with a historical perspective and physiological background of the phenomena of brain pulsatility as measured in the parenchyma and cerebrospinal fluid (CSF). We give a detailed account of how functional contrast mechanisms evident in the T2(*)-weighted MREG signal enable the simultaneous mapping of three distinct physiological signals. Our narrative review continues with an account of signal analysis and methodological considerations arising from 12 years of experience in ultrafast brain scanning. Our review concludes with a presentation of how sleep-related physiological changes in the driving pulsations influence solute transport in a healthy brain and our perspective on the potential of these pulsations as emerging biomarkers for predictive, diagnostic, and treatment monitoring in the context of Alzheimer's disease and other central nervous system (CNS) conditions.
在过去十年中，新型体内成像技术揭示了生理脉动驱动脑溶质的运输，并且流体流动受损先于某些神经病理学出现。尽管对脑溶质运输机制的开创性研究主要采用外源性示踪剂成像，但新型先进的超快功能磁共振成像序列能够对驱动脑液的传播生理脉动进行关键采样，避免信号的混叠混合。在这篇综述中，我们总结了新兴的磁共振脑成像（MREG）技术，首先从历史角度和在脑实质及脑脊液（CSF）中测量的脑脉动现象的生理背景说起。我们详细阐述了T2（*）加权MREG信号中明显的功能对比机制如何能够同时绘制三种不同的生理信号。我们的叙述性综述接着介绍了信号分析以及基于12年超快脑扫描经验所产生的方法学考量。我们的综述最后呈现了驱动脉动中与睡眠相关的生理变化如何影响健康大脑中的溶质运输，以及我们对于这些脉动作为阿尔茨海默病及其他中枢神经系统（CNS）疾病背景下预测、诊断和治疗监测的新兴生物标志物潜力的看法。
