title: Hypertension increases cerebral 6-18F-fluorodopa-derived radioactivity.
abstract: 6-(18)F-fluorodopa PET depicts the striatal dopaminergic lesion characterizing Parkinson disease (PD); however, striatal uptake of 6-(18)F-fluorodopa-derived radioactivity can be normal. Supine hypertension (SH) might increase 6-(18)F-fluorodopa uptake.
  
  
  METHODS
  We measured putamen, caudate, and occipital cortex 6-(18)F-fluorodopa-derived radioactivity and supine blood pressure in patients with PD + SH (systolic pressure >/= 180 mm Hg, n = 8), patients with PD without SH (PD - SH, n = 19), patients with pure autonomic failure (n = 8), and controls (n = 16).
  
  
  RESULTS
  Peak putamen radioactivity correlated with supine systolic pressure across all subjects and among PD patients and was higher in PD + SH than in PD - SH (P = 0.01). Both subgroups had rapid fractional declines in radioactivity between the peak and late values (P < 0.0001, compared with controls). Arterial 6-(18)F-fluorodopa concentrations were similar in the compared groups.
  
  
  CONCLUSIONS
  In PD, SH is associated with augmented striatal 6-(18)F-fluorodopa-derived radioactivity. Regardless of SH, retention of 6-(18)F-fluorodopa-derived radioactivity is markedly reduced. A model-independent approach can identify striatal dopaminergic denervation in PD.
authors.affiliation: Clinical Neurocardiology Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA. goldstein@ninds.nih.gov
authors.forename: David S
authors.initials: DS
authors.lastname: Goldstein
authors.forename: Courtney
authors.initials: C
authors.lastname: Holmes
authors.forename: Latoya
authors.initials: L
authors.lastname: Sewell
authors.forename: Irwin J
authors.initials: IJ
authors.lastname: Kopin
mesh_terms: D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism*; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000000981:diagnostic imaging / Q000378:metabolism*; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications / Q000000981:diagnostic imaging / Q000378:metabolism*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D014018:Tissue Distribution
chemical_list: D019275:Radiopharmaceuticals; C043437:fluorodopa F 18; D004295:Dihydroxyphenylalanine
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