title: Follow-up study of cardiac ¹²³I-MIBG scintigraphy in idiopathic REM sleep behavior disorder.
abstract: BACKGROUND
  Cardiac (123) I-metaiodobenzylguanidine ((123) I-MIBG) uptake in patients with idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD) is markedly reduced, as in Parkinson's disease (PD).
  
  
  METHODS
  We performed (123) I-MIBG scintigrams on patients with iRBD and PD. After the initial (123) I-MIBG scintigram, we retested subjects after a mean of 2.8 years.
  
  
  RESULTS
  The delayed heart-to-mediastinum (H/M) ratio of cardiac (123) I-MIBG uptake was not significantly reduced between the first and second study in either group (P = 0.050, P = 0.091, respectively). Follow-up imaging revealed a mean decline of 4.21 ± 9.06% or 6.40 ± 19.02% in the delayed H/M ratio in those with iRBD or PD, respectively.
  
  
  CONCLUSIONS
  The (123) I-MIBG uptake findings might indicate progression early in the course of iRBD or PD, but the progression is heterogeneous and independent of development of motor symptoms.
authors.affiliation: Department of Neurology, Center of Sleep Medicine, Dokkyo Medical University School of Medicine, Tochigi, Japan. sandra.olsson@neuro.gu.se
authors.forename: T
authors.initials: T
authors.lastname: Miyamoto
authors.forename: M
authors.initials: M
authors.lastname: Miyamoto
authors.forename: M
authors.initials: M
authors.lastname: Iwanami
authors.forename: K
authors.initials: K
authors.lastname: Hirata
mesh_terms: D019797:3-Iodobenzylguanidine; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000000981:diagnostic imaging / Q000209:etiology / Q000378:metabolism*; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D009206:Myocardium / Q000378:metabolism*; D020187:REM Sleep Behavior Disorder / Q000150:complications / Q000000981:diagnostic imaging / Q000378:metabolism*
chemical_list: D007457:Iodine Radioisotopes; D019797:3-Iodobenzylguanidine