Abnormal metabolic covariance patterns associated with multiple system atrophy and progressive supranuclear palsy

•Metabolic brain imaging can help differentiate between parkinsonian syndromes.•Metabolic brain patterns are robust and reproducible biomarkers of MSA and PSP.•Heat-maps present individual brain region's contribution to the metabolic pattern. Differentiation between neurodegenerative parkinsonisms, whose early clinical presentation is similar, may be improved with metabolic brain imaging. In this study we applied a specific network analysis to 2-[18F]FDG PET brain scans to identify the characteristic metabolic patterns for multiple system atrophy (MSA) and progressive supranuclear palsy (PSP) in a new European cohort. We also developed a new tool to recognize and estimate patients’ metabolic brain heterogeneity. 20 MSA-P patients, 20 PSP patients and 20 healthy controls (HC) underwent 2-[18F]FDG PET brain imaging. The scaled subprofile model/principal component analysis was applied to identify MSA/PSP-related patterns; MSARP and PSPRP. Additional, 56 MSA, 45 PSP, 116 PD and 61 HC subjects were analyzed for validation. We innovatively applied heat-map analysis to extract and graphically display the pattern’s regional sub-scores in individual subjects. MSARP was characterized by hypometabolism in cerebellum and putamen, and PSPRP by hypometabolism in medial prefrontal cortices, nucleus caudatus, frontal cortices and mesencephalon. Patterns’ expression discriminated between MSA/PSP patients and HCs as well as between different parkinsonian cohorts (p