Subarachnoid Space: New Tricks by an Old Dog

Andrzej F Frydrychowski,Pawel J Winklewski,Arkadiusz Szarmach,Bartosz Czaplewski,Wang Zhan

doi:10.1371/journal.pone.0037529

Andrzej F Frydrychowski, Pawel J Winklewski + Show 3 more

Open Access

https://doi.org/10.1371/journal.pone.0037529

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Abstract

PurposeThe purpose of the study was to: (1) evaluate the subarachnoid space (SAS) width and pial artery pulsation in both hemispheres, and (2) directly compare magnetic resonance imaging (MRI) to near-infrared transillumination/backscattering sounding (NIR-T/BSS) measurements of SAS width changes in healthy volunteers.MethodsThe study was performed on three separate groups of volunteers, consisting in total of 62 subjects (33 women and 29 men) aged from 16 to 39 years. SAS width was assessed by MRI and NIR-T/BSS, and pial artery pulsation by NIR-T/BSS.ResultsIn NIR-T/BSS, the right frontal SAS was 9.1% wider than the left (p<0.01). The SAS was wider in men (p<0.01), while the pial artery pulsation was higher in women (p<0.01). Correlation and regression analysis of SAS width changes between the back- and abdominal-lying positions measured with MRI and NIRT-B/SS demonstrated high interdependence between both methods (r = 0.81, p<0.001).ConclusionsNIR-T/BSS and MRI were comparable and gave equivalent modalities for the SAS width change measurements. The SAS width and pial artery pulsation results obtained with NIR-T/BSS are consistent with the MRI data in the literature related to sexual dimorphism and morphological asymmetries between the hemispheres. NIR-T/BSS is a potentially cheap and easy-to-use method for early screening in patients with brain tumours, increased intracranial pressures and other abnormalities. Further studies in patients with intracranial pathologies are warranted.

Highlights

The subarachnoid space (SAS) refers to the space between the arachnoid and the pia mater, the innermost membrane surrounding the central nervous system
The arachnoid is named for its delicate, spider-web-like filaments that extend from its undersurface through the cerebrospinal fluid (CSF) in the subarachnoid space to the pia mater. ‘‘Arachnoid’’ comes from the Greek ‘‘arachne’’ meaning spider or cobweb and ‘‘eidos’’ meaning resemblance, which in turn translates into spider-web-like
magnetic resonance imaging (MRI) measurements were performed by an experienced radiologist (AS), while NIR-T/BSS recordings were acquired by a different operator (AFF)

Summary

Introduction

The subarachnoid space (SAS) refers to the space between the arachnoid and the pia mater, the innermost membrane surrounding the central nervous system. The arachnoid is named for its delicate, spider-web-like filaments that extend from its undersurface through the cerebrospinal fluid (CSF) in the subarachnoid space to the pia mater. The SAS has been measured by various methods in children, mostly by ultrasonography [1,2]. For infants, an SAS width less than 4 mm is considered normal [3]. The SAS has been studied much less frequently in adults. There is one study in alcohol-dependent patients, where the mean SAS width was very close to 3 mm in the control group consisting of 10 healthy subjects [6]

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