Subarachnoid space: new tricks by an old dog

Area of Science:

• Neuroimaging
• Medical Physics
• Cerebrovascular Physiology

Background:

• The subarachnoid space (SAS) plays a crucial role in protecting the brain and regulating cerebrospinal fluid dynamics.
• Assessing SAS width and pial artery pulsation is important for diagnosing various neurological conditions.
• Existing methods like MRI are valuable but can be costly and time-consuming.

Purpose of the Study:

• To evaluate subarachnoid space (SAS) width and pial artery pulsation in both cerebral hemispheres.
• To directly compare magnetic resonance imaging (MRI) with near-infrared transillumination/backscattering sounding (NIR-T/BSS) for measuring SAS width changes in healthy volunteers.

Main Methods:

• Sixty-two healthy volunteers (16-39 years) were studied in three groups.
• Subarachnoid space (SAS) width was measured using both MRI and NIR-T/BSS.
• Pial artery pulsation was assessed using NIR-T/BSS.

Main Results:

• The right frontal SAS was found to be 9.1% wider than the left using NIR-T/BSS (p<0.01).
• SAS was wider in men, while pial artery pulsation was higher in women (p<0.01 for both).
• High correlation (r=0.81, p<0.001) was observed between MRI and NIR-T/BSS for SAS width changes in different body positions.

Conclusions:

• Near-infrared transillumination/backscattering sounding (NIR-T/BSS) and MRI provide comparable and equivalent measurements of SAS width changes.
• NIR-T/BSS results align with MRI data regarding sexual dimorphism and hemispheric asymmetries.
• NIR-T/BSS is a promising, cost-effective, and user-friendly method for early screening of intracranial pathologies.