title: [Validation of an optimal analysis method and reproducibility to calculate the heart-to-mediastinum ratio and washout rate in the iodine-123-labeled metaiodobenzylguanidine myocardial scintigraphy].
abstract: OBJECTIVE
  The aim of this study was to investigate an appropriate analysis method and multicenter reproducibility of heart-to-mediastinum ratio (H/M) and washout rate (WR) in iodine-123-labeled metaiodobenzylguanidine (123I-MIBG) myocardial scintigraphy with a phantom.
  
  
  METHODS
  We evaluated the optimal region of interest (ROI) setting method about the mediastinum and heart by varying the position and shape of the ROI. The mathematical method was changed to a combination of decay time correction (DTC) and background correction (BC). We evaluated the reproducibility of the H/M and WR between institutions.
  
  
  RESULTS
  H/M decreased to 23.49% and WR increased to 20.68% by changing the mediastinum ROI position from upper to lower. H/M increased to 26.03% by changing the heart ROI position from base to apex. H/M decreased to 38.36% with BC, and WR was reduced up to 48.51% with DTC. Reproducibility of the H/M and WR between institutions was improved by performing optimization of the ROI setting and unification of the mathematical method.
  
  
  CONCLUSIONS
  The position of the mediastinum ROI should be set on the upper mediastinum. The position of the heart ROI should be set on the apex of the heart. WR should be calculated with DTC and BC. Our results suggest that the reproducibility of the H/M and WR between institutions was improved by performing optimization of the ROI setting and unification of the mathematical method.
authors: Department of Image Diagnosis, Okayama Saiseikai General Hospital; Program in Health and Welfare, Graduate School of Comprehensive Scientific Research, Prefectural University of Hiroshima.
authors: Daisuke
authors: D
authors: Hasegawa
authors: Hideo
authors: H
authors: Onishi
authors: Norikazu
authors: N
authors: Matsutomo
authors: Yoshiharu
authors: Y
authors: Kangai
mesh_terms: D019797:3-Iodobenzylguanidine; D006321:Heart / Q000000981:diagnostic imaging*; D007457:Iodine Radioisotopes; D008432:Mathematical Computing; D008482:Mediastinum / Q000000981:diagnostic imaging; D019047:Phantoms, Imaging; D011877:Radionuclide Imaging / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results
chemical_list: D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine