title: Maximizing the sensitivity of the indirect radionuclide cystogram: a retrospective audit.
abstract: BACKGROUND
  The indirect radionuclide cystogram (IRC) has generally been reported as being less sensitive for detecting vesico-ureteric reflux (VUR) than the micturating cystourethrogram (MCUG), so we modified it in an attempt to increase its sensitivity.
  
  
  METHODS
  We altered our routine IRC protocol by including the data obtained during failed voids, adding extra imaging sequences at intervals during bladder filling, and by using simple mathematical criteria to determine if VUR was present when visual imaging results were equivocal. We then retrospectively compared the VUR detection rates using the standard and modified techniques.
  
  
  RESULTS
  We assessed 707 renal units in 356 children over 3 years. We identified 91 cases of VUR using standard methodology, and 134 (47% more) with the modified technique. Of the extra 43 cases detected, 11 were noted during failed voids, ten were seen within a filling sequence, and 22 were inferred because the renal pelvic activity increased during an interval between two imaging sequences, while the bladder was filling. Mathematical evaluation was helpful in the 39 cases where the increase in activity due to VUR was ≤6 standard deviations greater than the level of background variation in activity.
  
  
  CONCLUSIONS
  Additional imaging and mathematical assessment can significantly increase the sensitivity of the IRC for detecting VUR, possibly to equal that of the MCUG.
authors.affiliation: Regional Medical Physics Department, Royal Victoria Infirmary, Newcastle upon Tyne, NE1 4LP, UK, michael.keir@ncl.ac.uk.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Keir
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Lambert
authors.forename: Malcolm G
authors.initials: MG
authors.lastname: Coulthard
mesh_terms: D002675:Child, Preschool; D005260:Female; D015902:Gamma Cameras; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008485:Medical Audit; D015233:Models, Statistical; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000652:urine; D012189:Retrospective Studies; D017263:Technetium Tc 99m Mertiatide / Q000652:urine; D001743:Urinary Bladder / Q000000981:diagnostic imaging*; D014718:Vesico-Ureteral Reflux / Q000000981:diagnostic imaging*
chemical_list: D019275:Radiopharmaceuticals; D017263:Technetium Tc 99m Mertiatide