Human subarachnoid space width oscillations in the resting state

Marcin Gruszecki,Aneta Stefanovska,Wojciech Guminski,Andrzej F Frydrychowski,J Patrick Neary,Jacek Kot,Pawel J Winklewski,Ryan T Dech,Gemma Lancaster

doi:10.1038/s41598-018-21038-0

Abstract

Abnormal cerebrospinal fluid (CSF) pulsatility has been implicated in patients suffering from various diseases, including multiple sclerosis and hypertension. CSF pulsatility results in subarachnoid space (SAS) width changes, which can be measured with near-infrared transillumination backscattering sounding (NIR-T/BSS). The aim of this study was to combine NIR-T/BSS and wavelet analysis methods to characterise the dynamics of the SAS width within a wide range of frequencies from 0.005 to 2 Hz, with low frequencies studied in detail for the first time. From recordings in the resting state, we also demonstrate the relationships between SAS width in both hemispheres of the brain, and investigate how the SAS width dynamics is related to the blood pressure (BP). These investigations also revealed influences of age and SAS correlation on the dynamics of SAS width and its similarity with the BP. Combination of NIR-T/BSS and time-frequency analysis may open up new frontiers in the understanding and diagnosis of various neurodegenerative and ageing related diseases to improve diagnostic procedures and patient prognosis.

Highlights

The scalp and the skull lie the dura mater, the arachnoid, and the pia mater
Three signals were recorded simultaneously from 36 subjects: blood pressure (BP), TQLEFT (SAS width in left hemisphere) and TQRIGHT (SAS width in right hemisphere)
We investigated the dynamics of sub-arachnoid space (SAS) width oscillations, and how they are related to the blood pressure and, indirectly, blood flow

Summary

Introduction

The scalp and the skull lie the dura mater, the arachnoid, and the pia mater. The space between the arachnoid and the pia mater is known as the subarachnoid space (SAS) and is filled with translucent cerebrospinal fluid (CSF). As the brain is enclosed in a rigid skull, any increase in blood volume needs to be accompanied by a displacement of an approximately equal amount of CSF into the compliant spinal compartment to prevent an increase in intracranial pressure[1,3]. This induces oscillations in the CSF with the same frequency as the heartbeat. Considering that the SAS width is directly affected by the volume of cerebral vessels, it is likely that signatures of these blood flow oscillations will be transmitted to the CSF, and be observable as SAS width changes. Signatures of much lower frequency oscillations in SAS width were observed by Frydrychowski et al.[17] during the development of a novel method for the measurement of SAS width known as near-infrared transillumination-backscattering sounding (NIR-T/BSS) but were not investigated further

Objectives

Methods

Results

Conclusion