Diagnostic efficacy of parametric clearance images in detection of renal scars in children with recurrent urinary tract infections

Ann Nucl Med. 2015 Apr;29(3):313-8. doi: 10.1007/s12149-014-0944-4. Epub 2015 Jan 7.

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.

Conclusion: 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.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Child
  • Child, Preschool
  • Cysteine / analogs & derivatives
  • Female
  • Glycine / analogs & derivatives
  • Humans
  • Image Processing, Computer-Assisted
  • Kidney / diagnostic imaging*
  • Male
  • Organotechnetium Compounds
  • Prospective Studies
  • Radiopharmaceuticals
  • Recurrence
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Software
  • Technetium Tc 99m Dimercaptosuccinic Acid
  • Tomography, Emission-Computed, Single-Photon / methods
  • Urinary Tract Infections / diagnosis
  • Urinary Tract Infections / diagnostic imaging*

Substances

  • Organotechnetium Compounds
  • Radiopharmaceuticals
  • technetium Tc 99m-ethylenedicysteine
  • N-(mercaptoacetyl)glycine
  • Technetium Tc 99m Dimercaptosuccinic Acid
  • Cysteine
  • Glycine