A systematic approach to MR spectroscopy of the brain: Indications, protocol, metabolites, and spectral analysis in neurologic diseases

Magnetic resonance spectroscopy (MRS) is a noninvasive imaging technique that complements conventional magnetic resonance imaging by providing in vivo metabolic and biochemical characterization of brain tissue. By quantifying metabolites such as N-acetylaspartate, choline, creatine, lactate, and myo-inositol (myo-Ins), MRS offers insight into neuronal integrity, membrane turnover, energy metabolism, inflammation, and necrosis, features that help distinguish between pathologies with greater specificity than anatomic imaging alone.This review presents a clinically focused, systematic approach to brain MRS, addressing indications, acquisition strategies, spectral interpretation, and characteristic metabolic patterns across a broad spectrum of neuropathologies. Key technical factors influencing spectral quality and reproducibility, such as voxel selection, field strength, echo time, and sequence choice, are highlighted. Metabolic signatures of neoplastic, infectious, inflammatory, demyelinating, metabolic, and neurodegenerative disorders are reviewed with an emphasis on practical differentiation in the setting of overlapping imaging appearances. Recognizing the limited specificity of isolated metabolite abnormalities, this review emphasizes integration of MRS findings with clinical context and conventional MRI. A structured interpretive framework is proposed to promote consistent analysis and enhance diagnostic confidence, reinforcing the role of MRS as a valuable adjunct in contemporary neuroradiologic practice.