Cerebral metabolic trajectories alterations in multiple system atrophy: A longitudinal FDG-PET study

Area of Science:

• Neuroscience
• Nuclear Medicine
• Metabolic Imaging

Background:

• Multiple System Atrophy (MSA) is a progressive neurodegenerative disorder with distinct parkinsonian (MSA-P) and cerebellar (MSA-C) subtypes.
• Understanding the longitudinal metabolic changes in these subtypes is crucial for early diagnosis and tracking disease progression.

Purpose of the Study:

• To characterize longitudinal changes in glucose metabolism and network connectivity in MSA subtypes using 18F-FDG-PET.
• To correlate metabolic decline with clinical progression measured by the Unified Multiple System Atrophy Rating Scale (UMSARS).

Main Methods:

• Retrospective analysis of 29 MSA patients (17 MSA-P, 12 MSA-C) and 28 healthy controls using 18F-FDG-PET.
• Assessment of regional glucose uptake (Standardized Uptake Value Ratios) and inter-regional connectivity via correlation analysis.
• Modeling metabolic decline using nonlinear mixed-effects models and correlating with UMSARS scores.

Main Results:

• MSA-P showed progressive hypometabolism in the putamen, cerebellum, and frontal cortex.
• MSA-C exhibited declines primarily in the cerebellum and frontal regions.
• Longitudinal modeling revealed faster putaminal decline in MSA-P and cerebellar decline in both subtypes, correlating with UMSARS progression. Significant connectivity disruptions were observed.

Conclusions:

• Longitudinal FDG-PET imaging demonstrates distinct metabolic decline patterns in MSA subtypes: putamen in MSA-P and cerebellum in MSA-C.
• These patterns are linked to clinical severity and progression.
• FDG-PET can aid in biological staging, disease monitoring, and evaluating treatment efficacy in MSA clinical trials.