Creatine-weighted imaging in patients with Parkinson's disease.

Background: Parkinson's disease (PD) is a progressive neurodegenerative disorder involving impaired bioenergetics and mitochondrial dysfunction. Creatine (Cr) supplementation has been suggested as a pathophysiology-targeted therapy, yet human studies have yielded heterogeneous results. This study employs guanidino chemical exchange saturation transfer (GuanCEST) magnetic resonance imaging (MRI), a novel Cr-weighted imaging technique, to evaluate Cr level changes in patients with PD (PwPD) compared to healthy controls (HCs). Methods: 25 PwPD and 24 age- and sex-matched HCs underwent standardized clinical assessments and GuanCEST MRI. Region-of-interest (ROI) and voxel-wise analyses were conducted to assess group differences. Kendall's correlation and ANCOVA were used to explore associations between GuanCEST signals, disease presence, and clinical severity. Results: GuanCEST signals in the caudate nucleus were significantly lower in PwPD (1.67 ± 0.26%) than in HCs (1.82 ± 0.16%; p = 0.023). Signal reduction correlated with increasing PD severity, particularly in thalamic subregions. In the internal medullary lamina, GuanCEST values negatively correlated with MDS-UPDRS-III scores (r = -0.44, p = 0.03) and a trend was also seen in the lateral thalamic nuclei (r = -0.39, p = 0.06). ANCOVA indicated GuanCEST values in the internal medullary lamina decreased by ∼0.01% per point increase in MDS-UPDRS-III (p = 0.007), adjusted for age and sex. Conclusion: GuanCEST MRI shows promise as a non-invasive tool for detecting Cr alterations in PD. This technique may enhance our understanding of Cr metabolism in PD and support the development of targeted therapeutic strategies.