title: New semi-quantitative 123I-MIBG estimation method compared with scoring system in follow-up of advanced neuroblastoma: utility of total MIBG retention ratio versus scoring method.
abstract: OBJECTIVE
  The purpose of this study is to evaluate a new semi-quantitative estimation method using (123)I-MIBG retention ratio to assess response to chemotherapy for advanced neuroblastoma.
  
  
  METHODS
  Thirteen children with advanced neuroblastoma (International Neuroblastoma Risk Group Staging System: stage M) were examined for a total of 51 studies with (123)I-MIBG scintigraphy (before and during chemotherapy). We proposed a new semi-quantitative method using MIBG retention ratio (count obtained with delayed image/count obtained with early image with decay correction) to estimate MIBG accumulation. We analyzed total (123)I-MIBG retention ratio (TMRR: total body count obtained with delayed image/total body count obtained with early image with decay correction) and compared with a scoring method in terms of correlation with tumor markers.
  
  
  RESULTS
  TMRR showed significantly higher correlations with urinary catecholamine metabolites before chemotherapy (VMA: r(2) = 0.45, P < 0.05, HVA: r(2) = 0.627, P < 0.01) than MIBG score (VMA: r(2) = 0.19, P = 0.082, HVA: r(2) = 0.25, P = 0.137). There were relatively good correlations between serial change of TMRR and those of urinary catecholamine metabolites (VMA: r(2) = 0.274, P < 0.001, HVA: r(2) = 0.448, P < 0.0001) compared with serial change of MIBG score and those of tumor markers (VMA: r(2) = 0.01, P = 0.537, HVA: 0.084, P = 0.697) during chemotherapy for advanced neuroblastoma.
  
  
  CONCLUSIONS
  TMRR could be a useful semi-quantitative method for estimating early response to chemotherapy of advanced neuroblastoma because of its high correlation with urine catecholamine metabolites.
authors.affiliation: Department of Radiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan. yukyo-18@koto.kpu-m.ac.jp
authors.forename: Yuko
authors.initials: Y
authors.lastname: Sano
authors.forename: Chio
authors.initials: C
authors.lastname: Okuyama
authors.forename: Tomoko
authors.initials: T
authors.lastname: Iehara
authors.forename: Shigenori
authors.initials: S
authors.lastname: Matsushima
authors.forename: Kei
authors.initials: K
authors.lastname: Yamada
authors.forename: Hajime
authors.initials: H
authors.lastname: Hosoi
authors.forename: Tsunehiko
authors.initials: T
authors.lastname: Nishimura
mesh_terms: D019797:3-Iodobenzylguanidine / Q000493:pharmacokinetics*; D014408:Biomarkers, Tumor / Q000378:metabolism; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D009367:Neoplasm Staging; D009447:Neuroblastoma / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology*; D015203:Reproducibility of Results; D012107:Research Design; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; D019797:3-Iodobenzylguanidine