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. 2017 Jan;47(1):65-73.
doi: 10.1007/s00247-016-3721-9. Epub 2016 Oct 10.

Conversion and reliability of two urological grading systems in infants: the Society for Fetal Urology and the urinary tract dilatation classifications system

Miran Han  1 , Hyun Gi Kim  2 , Jung-Dong Lee  3 , Seon Young Park  1 , Young Keun Sur  1
Affiliations

Conversion and reliability of two urological grading systems in infants: the Society for Fetal Urology and the urinary tract dilatation classifications system

Miran Han et al. Pediatr Radiol. 2017 Jan.

Abstract

Background: The urinary tract dilation (UTD) classification system was proposed in 2014.

Objective: To evaluate the correspondence and reliability of two US grading systems for postnatal urinary tract dilatation in infants: the Society for Fetal Urology (SFU) and the UTD systems.

Materials and methods: We assessed 180 kidneys in infants younger than 1 year. Four radiologists assessed the kidneys twice using both the SFU system (grades 0 to 4) and the UTD system (grades normal, P1, P2, P3). The SFU system was re-categorized into SFU-A (grades 0, 1-2, 3, 4) and into SFU-B (grades 0-1, 2, 3, 4). The Cohen kappa statistic was used for estimating agreement of both UTD-SFU-A and UTD-SFU-B.

Results: The Cohen kappa was significantly higher between UTD and SFU-B as compared to the UTD and SFU-A (0.75 vs. 0.50, P < 0.001). Intra-observer agreement was similar for the two grading systems (SFU 0.64-0.88 vs. UTD 0.48-0.92, P = 0.050-0.885). SFU grades 2 and 3 showed fair to moderate inter-observer agreement and corresponding UTD grades P1 and P2 showed moderate to substantial agreement. The overall inter-observer agreement was significantly higher for the UTD system than for the SFU system during the first assessment (95% confidence interval [CI]: right kidney, -0.069 to -0.062; left kidney, -0.048 to -0.043).

Conclusion: Correspondence between the systems was poor using a recommended re-categorization (SFU-A). An alternative re-categorization (SFU-B) was found to be more appropriate for establishing correspondence between the systems. Both systems were reliable, with good intra- and inter-observer agreement for the assessment of infant kidneys, but the UTD system had better inter-observer agreement.

Keywords: Infants; Postnatal hydronephrosis; Reliability; Society for Fetal Urology classification system; Ultrasound; Urinary tract dilatation classification system.

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Comment in

  • Urinary tract dilation illustrations.
    Phelps AS, Chow JS, Back SJ, Nguyen HT, Koning JL, Darge K. Phelps AS, et al. Pediatr Radiol. 2017 Aug;47(9):1214-1215. doi: 10.1007/s00247-017-3916-8. Epub 2017 Aug 4. Pediatr Radiol. 2017. PMID: 28779205 No abstract available.

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