title: The difference of apparent diffusion coefficient in the middle cerebellar peduncle among parkinsonian syndromes: Evidence from a meta-analysis.
abstract: The measurement of middle cerebellar peduncle (MCP) width allows for differential diagnosis between Parkinson's disease (PD) and multiple system atrophy with predominant parkinsonian features (MSA-P). However, it remains controversial whether apparent diffusion coefficient (ADC) value in the MCP of MSA-P is elevated or not. In the present study, we aimed to assess the usefulness of ADC value in the MCP for differential diagnosis between PD and MSA-P. An on-line literature search yielded 5 eligible studies. We expressed between-group difference of ADC value as the standardized mean difference (SMD). The proportion of variation due to heterogeneity was computed and expressed as I(2). ADC in the MCP of MSA-P was significantly increased compared with PD with heterogeneous studies (P=0.0007, I(2)=81%). A meta-regression analysis of MSA-P was conducted for "UPDRS III", and revealed a significant correlation between UPDRS III and SMD (P=0.01). Our meta-regression analysis has clarified the contribution of severity of MSA-P to heterogeneity of the included studies for ADC in the MCP. This finding raised the possibility that ADC in the MCP depended on severity of MSA-P, and less severe patients with MSA-P should be mainly enrolled in future study to assess the ability for differential diagnostic tool.
authors.affiliation: Department of Clinical Neuroscience, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan. Electronic address: dwsako@yahoo.co.jp.
authors.forename: Wataru
authors.initials: W
authors.lastname: Sako
authors.affiliation: Department of Clinical Neuroscience, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: Nagahisa
authors.initials: N
authors.lastname: Murakami
authors.affiliation: Department of Clinical Neuroscience, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: Yuishin
authors.initials: Y
authors.lastname: Izumi
authors.affiliation: Department of Clinical Neuroscience, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: Ryuji
authors.initials: R
authors.lastname: Kaji
mesh_terms: D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D006801:Humans; D065837:Middle Cerebellar Peduncle / Q000000981:diagnostic imaging* / Q000378:metabolism; D019578:Multiple System Atrophy / Q000000981:diagnostic imaging* / Q000378:metabolism; D020734:Parkinsonian Disorders / Q000000981:diagnostic imaging* / Q000378:metabolism
keywords: Apparent diffusion coefficient; Meta-analysis; Middle cerebellar peduncle; Multiple system atrophy; Parkinson's disease; Progressive nuclear palsy