Application of multimodal MR imaging on studying Alzheimer's disease: a survey

Area of Science:

• Neuroimaging
• Radiology
• Neurology

Background:

• Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline.
• Magnetic Resonance Imaging (MRI) is a crucial non-invasive tool for studying brain alterations in AD.
• Various advanced MRI techniques provide complementary information on AD pathophysiology.

Purpose of the Study:

• To comprehensively review current Magnetic Resonance Imaging (MRI) variants used in Alzheimer's disease (AD) research.
• To present experimental findings, advantages, disadvantages, and future prospects of each MRI technique.
• To highlight MRI's capability in assessing brain volume, function, white matter integrity, and metabolic changes in AD.

Main Methods:

• Volumetric and morphological MRI analysis to quantify brain structure changes.
• Functional MRI (fMRI) using Blood Oxygen Level Dependent (BOLD) signals to assess brain activity.
• Diffusion Tensor Imaging (DTI) to evaluate white matter tract integrity.
• Other advanced techniques including Magnetic Resonance Spectroscopy (MRS), Chemical Shift Imaging (CSI), Arterial Spin Labeling (ASL), Magnetic Resonance Elastography (MRE), and Susceptibility Weighted Imaging (SWI).

Main Results:

• Volumetric analysis shows significant annual hippocampal reduction (18%-24% or 3%-4%).
• fMRI indicates early-stage AD affects medial temporal lobe structures (hippocampus, entorhinal cortex) and later stages affect broader cortical regions.
• DTI results on white matter integrity are currently inconsistent across studies.

Conclusions:

• MRI techniques are vital for understanding the spatiotemporal progression of brain changes in Alzheimer's disease.
• Different MRI variants offer unique insights into structural, functional, and microstructural alterations in AD.
• Further research and standardization of advanced MRI methods are needed to enhance diagnostic and prognostic capabilities for AD.