title: Cardiac 123I-MIBG scintigraphy can assess the disease severity and phenotype of PD.
abstract: OBJECTIVE
  Cardiac (123)I-metaiodobenzylguanidine (MIBG) scintigraphy studies of patients with idiopathic Parkinson's disease (PD) found decreased uptake. Whether this decrease is associated with clinical severity as assessed by the Unified Parkinson's Disease Rating Scale (UPDRS) and the phenotypes of PD has not been determined.
  
  
  METHODS
  Cardiac MIBG scintigraphy was performed on 34 patients with PD, 7 with multiple system atrophy (MSA), 4 with dementia with Lewy bodies (DLB), and 11 normal controls (NCs). Early and delayed MIBG heart/mediastinum (H/M) ratios were evaluated. PD severity was assessed by the Hoehn and Yahr (H-Y) stage and UPDRS. Patients were grouped in two phenotypes, tremor and postural instability gait difficulty (PIGD)-dominant groups based on UPDRS components. Associations between MIBG uptake and age at onset, UPDRS, and disease phenotype were analyzed in each group.
  
  
  RESULTS
  The early H/M ratio was significantly lower in patients with PD (1.45+/-0.207) than in the NCs (2.08+/-0.231), and in those with MSA (1.99+/-0.284), but not in those with DLB (1.29+/-0.0435). The delayed H/M ratio for PD (1.33+/-0.276) also was significantly decreased as compared to the ratios for NCs (2.17+/-0.286) and MSA (2.16+/-0.414) but not DLB (1.16+/-0.0949). The early H/M ratio was significantly correlated with both UPDRS score and age at onset, whereas the delayed H/M ratio only was significantly correlated with age at onset. The PIGD-dominant group had significantly higher UPDRS scores and lower H/M ratios than the tremor-dominant group.
  
  
  CONCLUSIONS
  Cardiac MIBG scintigraphy can be used to differentiate PD from MSA and NC, and to determine the disease severity and phenotypes of PD.
authors.affiliation: Department of Neurology, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Kahoku, Ishikawa 920-0923, Japan. saibon@kanazawa-med.ac.jp
authors.forename: Shinji
authors.initials: S
authors.lastname: Saiki
authors.forename: Genjiro
authors.initials: G
authors.lastname: Hirose
authors.forename: Koichiro
authors.initials: K
authors.lastname: Sakai
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kataoka
authors.forename: Ariyuki
authors.initials: A
authors.lastname: Hori
authors.forename: Misuzu
authors.initials: M
authors.lastname: Saiki
authors.forename: Muichi
authors.initials: M
authors.lastname: Kaito
authors.forename: Kotaro
authors.initials: K
authors.lastname: Higashi
authors.forename: Suzuka
authors.initials: S
authors.lastname: Taki
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kakeshita
authors.forename: Susumu
authors.initials: S
authors.lastname: Fujino
authors.forename: Miho
authors.initials: M
authors.lastname: Miaki
mesh_terms: D019797:3-Iodobenzylguanidine / Q000493:pharmacokinetics; D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D016022:Case-Control Studies; D004791:Enzyme Inhibitors / Q000493:pharmacokinetics; D005260:Female; D020234:Gait Ataxia / Q000175:diagnosis / Q000503:physiopathology; D006321:Heart / Q000187:drug effects*; D006801:Humans; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics; D020961:Lewy Body Disease / Q000175:diagnosis / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D019578:Multiple System Atrophy / Q000175:diagnosis / Q000503:physiopathology; D009460:Neurologic Examination; D010300:Parkinson Disease / Q000175:diagnosis* / Q000503:physiopathology; D010641:Phenotype; D011877:Radionuclide Imaging / Q000379:methods; D012044:Regression Analysis; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D014202:Tremor / Q000175:diagnosis / Q000503:physiopathology
chemical_list: D004791:Enzyme Inhibitors; D007457:Iodine Radioisotopes; D019797:3-Iodobenzylguanidine