title: 18F-FDG PET Is an Early Predictor of Overall Survival in Suspected Atypical Parkinsonism.
abstract: Early prognostic stratification is desirable in patients with suspected atypical parkinsonian syndromes (APSs) for optimal treatment and counseling. We investigated the prognostic value of imaging disease-specific metabolism patterns with 18F-FDG PET compared with that of clinical diagnosis.
  
  
  METHODS
  Seventy-eight patients with suspected APS at study inclusion underwent a follow-up of up to 5.9 y after prospective 18F-FDG PET imaging. Survival data were analyzed by Kaplan-Meier and Cox regression analyses according to diagnostic classifications provided by 18F-FDG PET at baseline and clinical diagnoses after a median follow-up of 1 y after PET.
  
  
  RESULTS
  Forty-four of 78 patients were alive 4.7±0.6 y after PET. Patients diagnosed with an APS by PET or 1-y clinical follow-up showed a significantly shorter median survival time (4.1 y, age-adjusted hazard ratios [HRs]=3.8 for both classifiers) than those diagnosed with Lewy-body diseases (LBDs; majority Parkinson disease [PD]; median survival time not reached). Subgroup classifications of progressive supranuclear palsy/corticobasal degeneration (PSP/CBD) or multiple-system atrophy (MSA) by PET and clinical follow-up were associated with significantly shorter survival than PD. Age-adjusted mortality was significantly increased for PSP/CBD (HR=5.2) and MSA (HR=5.6) classified by PET, but for PSP/CBD only when diagnosed by clinical follow-up (HR=4.5). Patients with a PET pattern suggestive of PD with dementia/dementia with Lewy bodies (PDD/DLB) exhibited a trend toward shorter survival than those with PD (P=0.07), whereas patients classified as PDD/DLB by clinical follow-up did not (P=0.65).
  
  
  CONCLUSIONS
  18F-FDG PET is an early predictor of survival in patients with clinically suspected APS. Detection of cortical or subcortical hypometabolism by 18F-FDG PET is an unfavorable predictor. Risk stratification by 18F-FDG PET appears to be at least as predictive as the 1-y follow-up clinical diagnosis. This finding strongly supports the early inclusion of PET imaging in patient care.
authors.affiliation: Department of Neurology, University Hospital of Freiburg, Freiburg, Germany Centre of Geriatrics and Gerontology, University Hospital of Freiburg, Freiburg, Germany sabine.hellwig@uniklinik-freiburg.de.
authors.forename: Sabine
authors.initials: S
authors.lastname: Hellwig
authors.affiliation: Centre of Geriatrics and Gerontology, University Hospital of Freiburg, Freiburg, Germany Department of Nuclear Medicine, University Hospital of Freiburg, Freiburg, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Frings
authors.affiliation: Department of Neurology, University Hospital of Freiburg, Freiburg, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Amtage
authors.affiliation: Department of Nuclear Medicine, Charité, Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Ralph
authors.initials: R
authors.lastname: Buchert
authors.affiliation: Department of Nuclear Medicine, University Hospital of Freiburg, Freiburg, Germany.
authors.forename: Timo S
authors.initials: TS
authors.lastname: Spehl
authors.affiliation: Department of Neurology, University Hospital of Freiburg, Freiburg, Germany.
authors.forename: Michel
authors.initials: M
authors.lastname: Rijntjes
authors.affiliation: Department of Neurology, University Hospital of Freiburg, Freiburg, Germany Department of Psychiatry, University Hospital Mainz, Mainz, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Tüscher
authors.affiliation: Department of Neurology, University Hospital of Freiburg, Freiburg, Germany.
authors.forename: Cornelius
authors.initials: C
authors.lastname: Weiller
authors.affiliation: Molecular Imaging and Therapy Service, Memorial Sloan Kettering Cancer Center, New York, New York; and.
authors.forename: Wolfgang A
authors.initials: WA
authors.lastname: Weber
authors.affiliation: Clinical Epidemiology, Institute of Medical Biometry and Medical Informatics, University of Freiburg, Freiburg, Germany.
authors.forename: Werner
authors.initials: W
authors.lastname: Vach
authors.affiliation: Department of Nuclear Medicine, University Hospital of Freiburg, Freiburg, Germany.
authors.forename: Philipp T
authors.initials: PT
authors.lastname: Meyer
mesh_terms: D000368:Aged; D005260:Female; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D020961:Lewy Body Disease / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000209:etiology / Q000503:physiopathology; D020734:Parkinsonian Disorders / Q000000981:diagnostic imaging* / Q000401:mortality; D049268:Positron-Emission Tomography / Q000379:methods*; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D019275:Radiopharmaceuticals; D013494:Supranuclear Palsy, Progressive / Q000000981:diagnostic imaging; D016019:Survival Analysis
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: 18F-FDG PET; atypical parkinsonian syndrome; parkinsonism; prognosis; survival