title: Differentiating multiple system atrophy from Parkinson's disease: contribution of striatal and midbrain MRI volumetry and multi-tracer PET imaging.
abstract: OBJECTIVE
  The differential diagnosis between typical idiopathic Parkinson's disease (PD) and the striatonigral variant of multiple system atrophy (MSA-P) is often difficult because of the presence of signs and symptoms common to both forms of parkinsonism, particularly at symptom onset. This study investigated striatal and midbrain findings in MSA-P and PD patients in comparison with normal controls with the use of positron emission tomography (PET) and three dimensional magnetic resonance imaging (3D MRI) based volumetry to increase the differential diagnostic accuracy between both disease entities.
  
  
  METHODS
  Nine patients with MSA-P, 24 patients with PD, and seven healthy controls were studied by MRI and PET with 6-[(18)F]-fluoro-L-dopa (FDOPA), [(18)F]fluoro-deoxyglucose (FDG), and 11-C-Raclopride (RACLO). Striatal and extrastriatal volumes of interest (VOI) were calculated on the basis of the individual MRI data. The PET data were transferred to the VOI datasets and subsequently analysed.
  
  
  RESULTS
  MSA-P differed significantly from PD patients in terms of decreased putaminal volume, glucose metabolism, and postsynaptic D2 receptor density. The striatal FDOPA uptake was equally impaired in both conditions. Neither MRI volumetry nor PET imaging of the midbrain region further contributed to the differential diagnosis between PD and MSA-P.
  
  
  CONCLUSIONS
  The extent and spatial distribution of functional and morphological changes in the striatum permit the differentiation of MSA-P from PD. Both, multi-tracer PET and 3D MRI based volumetry, may be considered equivalent in the assessment of different striatal abnormality in both disease entities. In contrast, MRI and PET imaging of the midbrain does not provide a further gain in diagnostic accuracy.
authors.affiliation: Neurology Department, University Hospital, Cologne, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Ghaemi
authors.forename: R
authors.initials: R
authors.lastname: Hilker
authors.forename: J
authors.initials: J
authors.lastname: Rudolf
authors.forename: J
authors.initials: J
authors.lastname: Sobesky
authors.forename: W-D
authors.initials: WD
authors.lastname: Heiss
mesh_terms: D001284:Atrophy / Q000473:pathology; D003342:Corpus Striatum / Q000378:metabolism* / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008636:Mesencephalon / Q000378:metabolism* / Q000473:pathology*; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis*; D011699:Putamen / Q000378:metabolism / Q000473:pathology; D019275:Radiopharmaceuticals; D014055:Tomography, Emission-Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18