Different loss of dopamine transporter according to subtype of multiple system atrophy.

Purpose: The aim of this study was to evaluate whether striatal dopamine transporter (DAT) loss as measured by F-fluorinated- N-3-fluoropropyl-2-b-carboxymethoxy-3-b-(4-iodophenyl) nortropane ([F]FP-CIT) PET differs according to the metabolic subtype of multiple system atrophy (MSA) as assessed by [F]FDG PET. Methods: This retrospective study included 50 patients with clinically diagnosed MSA who underwent [F]FP-CIT and [F]FDG brain PET scans. The PET images were analysed using 12 striatal subregional volume-of-interest templates (bilateral ventral striatum, anterior caudate, posterior caudate, anterior putamen, posterior putamen, and ventral putamen). The patients were classified into three metabolic subtypes according to the [F]FDG PET findings: MSA-P (striatal hypometabolism only), MSA-mixed (both striatal and cerebellar hypometabolism), and MSA-C (cerebellar hypometabolism only). The subregional glucose metabolic ratio (MR), subregional DAT binding ratio (BR), and intersubregional ratio (ISR; defined as the BR ratio of one striatal subregion to that of another striatal subregion) were compared according to metabolic subtype. Results: Of the 50 patients, 13 presented with MSA-P, 16 presented with MSA-mixed, and 21 presented with MSA-C. The BR of all striatal subregions in the MSA-P and MSA-mixed groups were significantly lower than those in the MSA-C group. The posterior putamen/anterior putamen ISR and anterior putamen/ventral striatum ISR in the MSA-P and MSA-mixed groups were significantly lower than those in the MSA-C group. Conclusion: Patients with MSA-P and MSA-mixed showed more severe DAT loss in the striatum than patients with MSA-C. Patients with MSA-C had more diffuse DAT loss than patients with MSA-P and MSA-mixed. [ABSTRACT FROM AUTHOR]