Variability of FP-CIT PET Patterns Associated With Clinical Features of Multiple System Atrophy

Abstract

Objective: To validate the role of the dopamine transporter (DAT) imaging as a biomarker in multiple system atrophy (MSA), we analyzed the association between spatial patterns of [¹⁸F]fluoro-propyl-carbomethoxy-iodophenyl-tropane ([¹⁸F]FP-CIT) PET and the clinical characteristics of MSA.

Methods: Sixty-five patients with MSA who underwent [¹⁸F]FP-CIT PET between 2009 and 2018 were retrospectively enrolled. To identify spatial patterns of [¹⁸F]FP-CIT PET, principal component (PC) analysis was used and correlated with the clinical presentation.

Results: Of the 65 patients, 42 presented with parkinsonian subtype of MSA, and 23 presented with cerebellar subtype of MSA (mean age 63.7 ± 9.3 years; disease duration, 1.8 ± 1.8 years). Each PC represents a specific pattern of degeneration: PC1 and PC2 were associated with the DAT binding of the entire putamen and the posterior putamen, respectively. PC3 was associated with increased [¹⁸F]FP-CIT uptake of the caudate and decreased uptake of the dorsal pons. PC2 was significantly correlated with the presence of parkinsonism (p = 5.34 × 10^-5) and a positive levodopa response (p = 0.044), with age as a cofactor. PC3 was correlated with the presence of urinary incontinence (p = 0.036). Onset age was significantly correlated with both PC2 (R = 0.48, p = 5.0 × 10^-5) and PC3 (R = -0.39, p = 0.0013).

Conclusions: The spatial pattern of DAT binding can reflect distinct clinical features of MSA and provides insight into the underlying pathophysiology of a broad spectrum of clinical features in MSA.