title: Inter-observer reproducibility in reporting on renal drainage in children with hydronephrosis: a large collaborative study.
abstract: OBJECTIVE
  The goal of this study was to evaluate the inter-observer reproducibility in reporting on renal drainage obtained during (99m)Tc MAG3 renography in children, when already processed data are offered to the observers.
  
  
  METHODS
  Because web site facilities were used for communication, 57 observers from five continents participated in the study. Twenty-three renograms, including furosemide stimulation and posterect postmicturition views, covering various patterns of drainage, were submitted to the observers. Images, curves and quantitative parameters were provided. Good or almost good drainage, partial drainage and poor or no drainage were the three possible responses for each kidney.
  
  
  RESULTS
  An important bias was observed among the observers, some of them more systematically reporting the drainage as being good, while others had a general tendency to consider the drainage as poor. This resulted in rather poor inter-observer reproducibility, as for more than half of the kidneys, less than 80% of the observers agreed on one of the three responses. Analysis of the individual cases identified some obvious causes of discrepancy: the absence of a clear limit between partial and good or almost good drainage, the fact of including or neglecting the effect of micturition and change of patient's position, the underestimation of drainage in the case of a flat renographic curve, and the difficulties of interpretation in the case of a small, not well functioning kidney.
  
  
  CONCLUSIONS
  There is an urgent need for better standardisation in estimating the quality of drainage.
authors.affiliation: Département des Radio-Isotopes, CHU Saint-Pierre, Rue Haute 322, Brussels, Belgium. Marianne_Tondeur@stpierre-bru.be
authors.forename: Marianne
authors.initials: M
authors.lastname: Tondeur
authors.forename: Diego
authors.initials: D
authors.lastname: De Palma
authors.forename: Isabel
authors.initials: I
authors.lastname: Roca
authors.forename: Amy
authors.initials: A
authors.lastname: Piepsz
authors.forename: Hamphrey
authors.initials: H
authors.lastname: Ham
mesh_terms: D002648:Child; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D006869:Hydronephrosis / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D008297:Male; D015588:Observer Variation; D011866:Radioisotope Renography / Q000706:statistics & numerical data*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017263:Technetium Tc 99m Mertiatide
chemical_list: D019275:Radiopharmaceuticals; D017263:Technetium Tc 99m Mertiatide