title: Diagnostic efficacy of parametric clearance images in detection of renal scars in children with recurrent urinary tract infections.
abstract: OBJECTIVE
  Static renal scintigraphy with Tc-99m dimercaptosuccinic acid (DMSA) is considered a scintigraphic gold standard in detection of post-inflammatory renal scars. Reports on usefulness of conventional summed (SUM) Tc-99 m mercaptoacetyltriglycine (MAG3) or Tc-99m ethylene dicysteine (EC) dynamic scintigraphic images in detection of renal scarring are ambiguous and some authors emphasize low sensitivity of this method. The work aimed at assessment of a diagnostic efficacy of parametric clearance images (PAR) generated from a dynamic renal scintigraphy in detection of renal scars.
  
  
  METHODS
  A study group consisting of 80 children (56 girls, 24 boys, age 5-18 years) with recurrent urinary tract infections (UTI) and documented one to five incidents of APN-28 children, and with recurrent UTI of the lower part of the urinary tract only-52 children. Altogether 160 kidneys were evaluated. Static renal Tc-99m DMSA SPECT scintigraphy and after 2-4 days Tc-99m EC dynamic renal scintigraphy were performed in every patient not earlier than 6 months after the last documented incident of UTI. PAR images generated from a dynamic renal scintigraphy acquired between 40 and 140 s. generated by in-house developed software and SUM images obtained in the same time period were compared with a reference Tc-99m DMSA SPECT study.
  
  
  RESULTS
  For all kinds of images (SPECT, PAR and SUM), high indices of reproducibility were obtained-89 % (κ = 0.80), 88 % (κ = 0.78) and 89 % (κ = 0.73). Agreement in a Howard scale of a reference method (SPECT) with PAR and SUM methods amounted to 83 and 64 %, respectively (p = 0.004). Sensitivity and accuracy of PAR method as compared with SUM method were significantly higher: 89 vs. 49 % (p < 0.0001) and 88 vs. 73 % (p = 0.002), and specificity was slightly lower: 88 vs. 93 % (p = 0.043). SPECT and PAR methods revealed higher incidence of renal scars than a SUM method in patients with documented incident(s) of APN-64, 68 and 39 %, p = 0.009 and 0.008, respectively.
  
  
  CONCLUSIONS
  PAR images generated from a dynamic renal scintigraphy improved sensitivity of detection of renal scars as compared with SUM images, providing a high reproducibility and diagnostic efficacy, similar to that of Tc-99m DMSA, in detection of post-inflammatory renal scarring.
authors.affiliation: Department of Nuclear Medicine, Inter-Faculty Chair of Medical Imaging and Radiology, Medical University, Łódź, Poland.
authors.forename: Jacek
authors.initials: J
authors.lastname: Kuśmierek
authors.forename: Ewa
authors.initials: E
authors.lastname: Pietrzak-Stelmasiak
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Bieńkiewicz
authors.forename: Wojciech
authors.initials: W
authors.lastname: Woźnicki
authors.forename: Marian
authors.initials: M
authors.lastname: Surma
authors.forename: Izabela
authors.initials: I
authors.lastname: Frieske
authors.forename: Anna
authors.initials: A
authors.lastname: Płachcińska
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003545:Cysteine / Q000031:analogs & derivatives; D005260:Female; D005998:Glycine / Q000031:analogs & derivatives; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007668:Kidney / Q000000981:diagnostic imaging*; D008297:Male; D015609:Organotechnetium Compounds; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D012008:Recurrence; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012984:Software; D019783:Technetium Tc 99m Dimercaptosuccinic Acid; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D014552:Urinary Tract Infections / Q000175:diagnosis / Q000000981:diagnostic imaging*
chemical_list: D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C073806:technetium Tc 99m-ethylenedicysteine; C096273:N-(mercaptoacetyl)glycine; D019783:Technetium Tc 99m Dimercaptosuccinic Acid; D003545:Cysteine; D005998:Glycine