Magnetic resonance spectroscopy in AD.

Area of Science:

• Neuroimaging
• Biochemistry
• Neurology

Background:

• Alzheimer's disease (AD) diagnosis relies on clinical assessment and biomarkers.
• Proton MR spectroscopy (MRS) offers a non-invasive method to investigate brain metabolite changes in vivo.
• Previous studies suggest alterations in specific metabolites in AD patients.

Purpose of the Study:

• To review the role of MRS in detecting and understanding Alzheimer's disease.
• To explore the diagnostic potential and pathophysiological insights provided by MRS in AD.

Main Methods:

• Analysis of proton MRS studies investigating metabolite changes in various brain regions of AD patients.
• Review of phosphorous MRS findings and their correlation with disease progression and pathology.
• Examination of automated MRS for AD diagnosis and its limitations.

Main Results:

• Consistent findings of decreased N-acetylaspartate (NAA) and increased myo-inositol in multiple brain regions of AD patients, even in early stages.
• NAA decline is independent of atrophy, suggesting reduced neurocellular viability.
• Emerging evidence of these metabolite changes in mild cognitive impairment (MCI) prodrome.
• Inconclusive results for in vivo neural choline quantitation due to repeatability issues.
• Phosphorous MRS shows phosphocreatine decline and phosphomonoester increments in early AD, which normalize with progression.
• Phosphodiester concentration correlates with AD plaque counts.

Conclusions:

• MRS provides valuable insights into AD pathophysiology, suggesting neurochemical changes precede significant atrophy.
• MRS shows potential for early AD detection, prediction of cognitive status, and monitoring therapeutic response.
• Further validation with prospective samples and multiple regions of interest is needed for automated MRS in AD diagnosis.