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

Abstract

<h3>Objective</h3> 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. <h3>Methods</h3> 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. <h3>Results</h3> 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 (<i>p</i> = 5.34 × 10⁻⁵) and a positive levodopa response (<i>p</i> = 0.044), with age as a cofactor. PC3 was correlated with the presence of urinary incontinence (<i>p</i> = 0.036). Onset age was significantly correlated with both PC2 (<i>R</i> = 0.48, <i>p</i> = 5.0 × 10⁻⁵) and PC3 (<i>R</i> = −0.39, <i>p</i> = 0.0013). <h3>Conclusions</h3> 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.