Biomarkers

Area of Science:

• Neuroimaging
• Biomedical Engineering
• Neurology

Background:

• Neurofluid exchange is crucial for brain health; disruptions are implicated in Alzheimer's disease and related dementias (ADRD).
• Amyloid-related imaging abnormalities (ARIA) are a clinical manifestation associated with ADRD.
• Assessing neurofluid dynamics is key to understanding neurodegenerative disease mechanisms.

Purpose of the Study:

• To discuss advances in non-contrast MRI for evaluating neurofluid exchange at multiple brain interfaces.
• To explore the application of these MRI techniques in the context of ADRD and ARIA.
• To highlight the potential of MRI in assessing blood-brain barrier (BBB) permeability, arterial integrity, and glymphatic function.

Main Methods:

• Utilizing non-contrast MRI to image blood-brain barrier (BBB) permeability to water.
• Employing MRI to assess arterial vessel integrity as a marker for microbleed and ARIA risk.
• Measuring water exchange between interstitial fluid (ISF) and perivascular space (PVS) using MRI to evaluate glymphatic function.

Main Results:

• Elevated BBB permeability to water was observed in mild cognitive impairment (MCI) patients, correlating with CSF biomarkers and cognitive scores.
• Animal models confirmed increased BBB permeability in Alzheimer's disease (AD) models, reversible with treatment.
• Long echo-time Arterial Spin-Labeling (ASL) MRI shows potential for identifying ARIA risks and assessing glymphatic function.

Conclusions:

• Advanced MRI techniques enable the assessment of neurofluid exchange across critical brain interfaces.
• These MRI methods offer valuable insights into the role of neurofluid dynamics in neurodegenerative disease pathogenesis.
• Non-contrast MRI holds promise for early detection and monitoring of conditions like ADRD and ARIA.