Background <p>Idiopathic Parkinson disease (IPD) is a progressive neurodegenerative disorder (NDD) characterized by dopaminergic neuronal loss. Magnetic Resonance Spectroscopy (MRS) is a non-invasive imaging tool that permits in vivo detection of metabolic changes in brain tissue.</p> Objective <p>This study aimed to evaluate the diagnostic and prognostic value of magnetic resonance spectroscopy metabolite ratios in cases with IPD and to investigate their correlation with disease severity.</p> Methods <p>A case observational study was conducted on 71 patients with clinically diagnosed IPD and 71 age- and sex-matched healthy controls. Proton magnetic resonance spectroscopy was performed using a 1.5&#xa0;T Magnetic Resonance Imaging (MRI) scanner, and metabolite ratios: N-Acetyl Aspartate (NAA)/Creatine (Cr), NAA/Choline (Cho), and Cho/Cr were analyzed in the caudate nucleus, lentiform nucleus, and substantia nigra (SN). Clinical severity was evaluated using the Unified Parkinson Disease Rating Scale (UPDRS) and Hoehn and Yahr (H and Y) staging.</p> Results <p>Patients with disease showed significantly diminished NAA/Cr and NAA/Cho ratios, and elevated Cho/Cr ratios in all examined regions (<i>p</i> &lt; 0.001). NAA-based ratios had a strong negative relationship with the Unified Parkinson Disease Rating Scale scores and Hoehn and Yahr stage. Receiver Operating Characteristic (ROC) analysis demonstrated high diagnostic accuracy of magnetic resonance spectroscopy metabolite ratios, particularly in the substantia nigra.</p> Conclusions <p>Magnetic resonance spectroscopy is a valuable adjunct in evaluating IPD severity and may support diagnosis, especially with advanced imaging protocols. The NAA/Cr ratio in the substantia nigra shows promise as a biomarker for disease progression. Further studies using higher field strength and drug-naïve patients are warranted.</p>