Advancements in Imaging Biomarkers for Early Diagnosis and Monitoring of Alzheimer's Disease: Comprehensive Review

Abstract

Background: Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline and memory loss. Increasing prevalence necessitates early and accurate diagnosis, as current treatment options are limited and primarily symptomatic.

Methods: This comprehensive review examines contemporary imaging biomarkers used for the early diagnosis and monitoring of AD. Emphasis is placed on structural and functional neuroimaging techniques, particularly magnetic resonance imaging (MRI) and positron emission tomography (PET). The review categorizes biomarkers according to the "A/T/N" classification system, which includes amyloid (A), tau (T), and neurodegeneration (N) components.

Results: Key findings indicate that amyloid deposition is often the earliest detectable change, while tau accumulation correlates more closely with clinical symptoms of cognitive decline. Innovative methodologies, such as voxel-based morphometry and diffusion tensor imaging, enhance the sensitivity of MRI in identifying structural brain changes. PET imaging with novel tracers, including those for synaptic density and iron accumulation, shows promise for early detection and monitoring disease progression. Despite advancements, existing biomarkers face challenges regarding specificity and reliability, which can hinder their clinical utility.

Conclusion: The review underscores the critical role of imaging biomarkers in the early detection and ongoing monitoring of Alzheimer's disease. While current imaging techniques provide valuable insights, further research is required to validate new biomarkers and improve existing methodologies. The development of robust, non-invasive biomarkers is essential for enhancing early diagnosis and facilitating timely therapeutic interventions.