title: WWSSF - a worldwide study on radioisotopic renal split function: reproducibility of renal split function assessment in children.
abstract: OBJECTIVE
  The split or differential renal function is the most widely accepted quantitative parameter derived from radionuclide renography. To examine the intercenter variance of this parameter, we designed a worldwide round robin test.
  
  
  METHODS
  Five selected dynamic renal studies have been distributed all over the world by e-mail. Three of these studies are anonymized patient data acquired using the EANM standardized protocol and two studies are phantom studies. In a simple form, individual participants were asked to measure renal split function as well as to provide additional information such as data analysis software, positioning of background region of interest, or the method of calculation.
  
  
  RESULTS
  We received the evaluation forms from 34 centers located in 21 countries. The analysis of the round robin test yielded an overall z-score of 0.3 (a z-score below 1 reflecting a good result). However, the z-scores from several centers were unacceptably high, with values greater than 3. In particular, the studies with impaired renal function showed a wide variance.
  
  
  CONCLUSIONS
  A wide variance in the split renal function was found in patients with impaired kidney function. This study indicates the ultimate importance of quality control and standardization of the measurement of the split renal function. It is especially important with respect to the commonly accepted threshold for significant change in split renal function by 10%.
authors.affiliation: aDepartment of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna bCenter for Medical Physics and Biomedical Engineering, Vienna, Austria cInstitute of Nuclear Medicine, Charles University Prague, Prague, Czech Republic.
authors.forename: Barbara Katharina
authors.initials: BK
authors.lastname: Geist
authors.forename: Georg
authors.initials: G
authors.lastname: Dobrozemsky
authors.forename: Martin
authors.initials: M
authors.lastname: Samal
authors.forename: Michael P
authors.initials: MP
authors.lastname: Schaffarich
authors.forename: Helmut
authors.initials: H
authors.lastname: Sinzinger
authors.forename: Anton
authors.initials: A
authors.lastname: Staudenherz
mesh_terms: D002648:Child; D006801:Humans; D038622:Internationality; D007668:Kidney / Q000000981:diagnostic imaging* / Q000502:physiology*; D007677:Kidney Function Tests / Q000379:methods*; D011868:Radioisotopes; D011877:Radionuclide Imaging; D015203:Reproducibility of Results
chemical_list: D011868:Radioisotopes