Molecular and Microstructural MRI of Neuroinflammation in Alzheimer's Disease.

INTRODUCTION

Alzheimer's disease (AD) is a leading cause of cognitive decline in older adults, often diagnosed late when pathology and symptoms are established, reducing treatment effectiveness. Both AD and mild cognitive impairment (MCI) trigger neuroinflammation, leading to molecular and microstructural changes, including oxidative stress, mitochondrial dysfunction, glial activation, synaptic and neurotransmitter disturbances, myelin degradation, and white matter dysfunction. The blood-brain barrier (BBB) is also compromised.

METHODS

Advanced magnetic resonance imaging (MRI) techniques, such as magnetic resonance spectroscopy (MRS), diffusion tensor imaging (DTI), diffusion kurtosis imaging (DKI), magnetization- transfer imaging (MTI), chemical exchange saturation transfer (CEST), contrast-enhanced MRI (CE-MRI), and arterial spin labeling (ASL), offer promise for the early detection of Alzheimer's disease (AD)-related molecular and microstructural changes.

RESULTS

Based on recent studies, advanced MRI modalities-including magnetic resonance spectroscopy, diffusion imaging, contrast-enhanced imaging, and chemical shift imaging-can highlight metabolic dysfunction, white matter degradation, microstructural disruption, blood-brain barrier dysfunction, cerebral hypoperfusion, vascular dysfunction, and pH alterations caused by neuroinflammation in Alzheimer's patients.

DISCUSSION: The integration of advanced MRI modalities into clinical practice could improve the diagnosis and management of Alzheimer's disease (AD). Magnetic resonance spectroscopy and diffusion imaging can identify metabolic and microstructural changes years before brain atrophy occurs, aiding professionals in the early detection of AD. Additionally, perfusion imaging and magnetization transfer imaging can help distinguish between Alzheimer's disease, frontotemporal dementia (FTD), and vascular dementia. Finally, contrast-enhanced MRI can monitor the integrity of the blood-brain barrier to evaluate responses to drug treatments.

CONCLUSION

Despite challenges, such as longer scan times and limited specificity, advanced MRIbased approaches are at the forefront of identifying reliable biomarkers for early detection of Alzheimer's disease and determining optimal management and treatment strategies.