title: Patterns of gray matter atrophy in atypical parkinsonism syndromes: a VBM meta-analysis.
abstract: OBJECTIVE
  Accurate diagnosis of Atypical Parkinsonian Syndromes (APS) is important due to differences in prognosis and management, but remains a challenge in the clinical setting. The purpose of our meta-analysis was to identify characteristic patterns of gray matter atrophy in Corticobasal Degeneration (CBD), Progressive Supranuclear Palsy (PSP), Multisystem-Atrophy Parkinsonian type (MSA-P), and Idiopathic Parkinson's Disease (IPD).
  
  
  METHODS
  Whole-brain meta-analysis was performed on 39 published voxel-based morphometry (VBM) articles (consisting of 404 IPD, 87 MSA-P, 165 CBD, and 176 PSP subjects) using the modified Anatomic Likelihood Estimation method. Based on these results, contrast analyses were then utilized to determine areas of atrophy shared by as well as unique to each disorder.
  
  
  RESULTS
  CBD was characterized by asymmetric gray matter atrophy in multiple cortical regions, while the thalamus-midbrain and insula were predominantly involved in PSP. The striatum and superior cerebellum were affected in MSA-P, while IPD demonstrated an anterior cerebral pattern. Although there was a mild overlap among PSP, CBD, and MSA-P, significant regions of atrophy unique to each disorder were identified, including (1) the superior parietal lobule in CBD (2) putamen in MSA-P (3) insula and medial dorsal nucleus in PSP.
  
  
  CONCLUSIONS
  Our results suggest that there are characteristic patterns of atrophy in APS. Guided by these findings, future studies on the individual subject level may lead to the development of robust imaging biomarkers.
authors.affiliation: Department of Radiology, University of Texas Health Science Center San Antonio, Texas ; Research Imaging Institute San Antonio, Texas.
authors.forename: Fang
authors.initials: F
authors.lastname: Yu
authors.affiliation: Department of Radiology, University of Texas Health Science Center San Antonio, Texas ; Research Imaging Institute San Antonio, Texas.
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Barron
authors.affiliation: Department of Radiology, University of Texas Health Science Center San Antonio, Texas ; Research Imaging Institute San Antonio, Texas.
authors.forename: Bundhit
authors.initials: B
authors.lastname: Tantiwongkosi
authors.affiliation: Department of Radiology, University of Texas Health Science Center San Antonio, Texas ; Research Imaging Institute San Antonio, Texas.
authors.forename: Peter
authors.initials: P
authors.lastname: Fox
mesh_terms: D003937:Diagnosis, Differential; D066128:Gray Matter / Q000473:pathology*; D006801:Humans; D016013:Likelihood Functions; D019578:Multiple System Atrophy / Q000175:diagnosis*; D009929:Organ Size; D020734:Parkinsonian Disorders / Q000175:diagnosis*; D013223:Statistics as Topic; D013494:Supranuclear Palsy, Progressive / Q000175:diagnosis*
keywords: Neurodegenerative diseases; Parkinson's disease; neuroimaging