The combination of the 18F-FDG PET and susceptibility-weighted imaging for diagnosis of cerebral glucose metabolism and iron deposition in Parkinson's disease

Abstract

This study aimed to evaluate the diagnostic potential of combining ¹⁸F-FDG PET and susceptibility-weighted imaging (SWI) to assess cerebral glucose metabolism and iron deposition patterns in Parkinson's disease (PD), and to determine their correlations with clinical progression and diagnostic accuracy. Forty-nine PD patients and 70 age-/sex-matched healthy controls underwent standardized ¹⁸F-FDG PET and SWI. Metabolic activity (SUVR) and SWI phase values were quantified in cortical/subcortical regions. Statistical analyses included Mann-Whitney U tests, Pearson/Spearman correlations, and ROC curve analysis to evaluate biomarker-clinical relationships and diagnostic performance. PD patients exhibited hypometabolism in frontal, parietal, and temporal cortices (P < 0.05) and hypermetabolism in the putamen, globus pallidus, and cerebellum (P < 0.05). Cortical hypometabolism correlated with Hoehn-Yahr (H-Y) stages (e.g., temporal lobe: r = - 0.405, P = 0.004) and UPDRS III scores (e.g., frontal cortex: r = - 0.364, P = 0.011). SWI revealed reduced phase values in the substantia nigra, red nucleus, and basal ganglia (P < 0.001), with substantia nigra phase values strongly correlating with H-Y stages (r = - 0.525) and UPDRS III scores (r = - 0.446). Multimodal integration of ¹⁸F-FDG PET and SWI achieved superior diagnostic accuracy (AUC = 0.844) compared to single-modality models (PET: AUC = 0.777; SWI: AUC = 0.780, P < 0.0001). The integration of ¹⁸F-FDG PET and SWI enhances PD diagnosis by capturing complementary metabolic and iron deposition biomarkers. Cortical hypometabolism may precede subcortical iron accumulation, aligning with Braak staging theory. Limitations include cross-sectional design and technical constraints in SWI quantification. Future studies should validate these findings with longitudinal cohorts and advanced techniques like QSM.

Keywords: 18F-FDG PET; Diagnostic accuracy; Iron deposition; Multimodal biomarkers; Parkinson’s disease; Susceptibility-weighted imaging.

Fig. 1

The images presented depict ¹⁸F-FDG uptakes in PET imaging of HC individual (A) and patient with PD (B). (A) HC group individual, man, 68 years. The ¹⁸F-FDG PET imaging show a symmetric distribution pattern of the cerebral cortex and nigrostriatal regions, with no apparent areas of increased or decreased radioactive uptake, or mild frontal cortex metabolic reduction caused by normal aging. (B) A 74-year-old male with PD. The FDG PET imaging revealed local cortical metabolism reduction in the frontal, parietal, or temporal cortical regions, and increased metabolism in the cerebellum.

Fig. 2

The correlation between the FDG uptake and H&Y stages and UPDRS III score.

Fig. 3

The images presented the SWI of an HC individual (A) and a patient with PD (B). (A) HC group individual, man, 68 years. The SWI clearly shows the bilateral caudate, putamen, globus pallidus, substantia nigra, and red nucleus, with no obvious abnormal signals. (B) A 74-year-old male with PD. The SWI revealed signal reduction in the bilateral caudate, putamen, globus pallidus, substantia nigra, and red nucleus caused by iron deposition.

Fig. 4

Comparative analysis of phase values for both the PD and HC subjects in the SWI imaging. HC, healthy control; PD, Parkinson’s disease; ASI, asymmetry index.

Fig. 5

The correlation between the SWI phase values and H&Y stages and UPDRS III score.

Fig. 6

ROC curve analysis of the ¹⁸F-FDG PET, SWI model and PET + SWI model in differentiating early PD from HC.