title: Brain magnetic resonance imaging in multiple-system atrophy and Parkinson disease: a diagnostic algorithm.
abstract: BACKGROUND
  Brain magnetic resonance (MR) imaging offers the potential for objective criteria in the differential diagnosis of multiple system atrophy with predominant parkinsonism (MSA-P) and Parkinson disease (PD), since it frequently shows characteristic abnormalities in patients with MSA-P and is believed to be normal in patients with PD.
  
  
  OBJECTIVE
  To determine concordance between clinical and MR imaging-based diagnoses of MSA-P and PD.
  
  
  METHODS
  Two neuroradiologists identified and rated striatal and infratentorial abnormalities in 39 brain MR images and assigned a diagnosis of PD, MSA-P, or MSA with additional marked cerebellar ataxia (MSA-C).
  
  
  METHODS
  Academic medical center.
  
  
  METHODS
  Thirty-nine patients with parkinsonism, including 21 with a clinical diagnosis of PD, 14 with MSA-P, and 4 with MSA-C.
  
  
  RESULTS
  All patients with MSA and 14 (67%) of 21 patients with PD had some abnormality on brain MR imaging. Brainstem atrophy was seen in patients with MSA-P and MSA-C. Putaminal atrophy was seen only in MSA-P. Putaminal hypointensity and lateral slitlike hyperintensity were seen in both PD and MSA-P but were always mild in PD. Cerebellar abnormalities, seen in all patients with MSA-C and 11 patients with MSA-P, were also identified in 6 patients with PD, albeit always rated as mild. Nonconcordance between clinical and radiological diagnosis occurred in 2 patients with PD, 5 with MSA-P, and 1 with MSA-C.
  
  
  CONCLUSIONS
  Since several features on brain MR imaging are seen only in MSA-P, a simple diagnostic algorithm may improve the MR imaging diagnosis of MSA-P and PD.
authors.affiliation: Department of Neurology, Mount Sinai School of Medicine, Campus Box 1052, New York, NY 10029, USA.
authors.forename: Kirsty
authors.initials: K
authors.lastname: Bhattacharya
authors.forename: Daniela
authors.initials: D
authors.lastname: Saadia
authors.forename: Barbara
authors.initials: B
authors.lastname: Eisenkraft
authors.forename: Melvin
authors.initials: M
authors.lastname: Yahr
authors.forename: Warren
authors.initials: W
authors.lastname: Olanow
authors.forename: Burton
authors.initials: B
authors.lastname: Drayer
authors.forename: Horacio
authors.initials: H
authors.lastname: Kaufmann
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D001933:Brain Stem / Q000473:pathology; D002531:Cerebellum / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019578:Multiple System Atrophy / Q000473:pathology*; D010300:Parkinson Disease / Q000473:pathology*; D013378:Substantia Nigra / Q000473:pathology