Presynaptic Striatal Dopaminergic Function in Atypical Parkinsonism: A Metaanalysis of Imaging Studies

The purpose of this study was to determine whether striatal positron emission tomography (PET) and single-photon emission computed tomography (SPECT) imaging could be used to differentiate the atypical parkinsonian disorders multiple-system atrophy (MSA), progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS) from the typical Parkinson disease (PD) for clinical and differential diagnostic purposes. Presynaptic tracers for dopamine transporter (DAT), aromatic amino acid decarboxylase (AADC) and vesicular monoamine type 2 (VMAT2) were investigated. A metaanalysis of 35 published presynaptic dopaminergic brain imaging studies of parkinsonian disorder patients and healthy controls was performed. PubMed was screened for eligible studies, and studies that fulfilled inclusion criteria determined by the study group were identified and included. Available striatal tracer binding values, disease severity scores as well as data concerning imaging methodology were extracted manually from the included studies. Collected data was synthesized using Meta-Essentials, with a statistical significance cut-off at 2-tailed P