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Pediatr Radiol. 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.

Author information

1
Department of Radiology, Ajou University School of Medicine, Ajou University Medical Center, 164 World cup-ro, Yeongtong-gu, Suwon, Korea, 443-380.
2
Department of Radiology, Ajou University School of Medicine, Ajou University Medical Center, 164 World cup-ro, Yeongtong-gu, Suwon, Korea, 443-380. catharina315@aumc.ac.kr.
3
Office of Biostatistics, Ajou University School of Medicine, Suwon, Korea.

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

Comment in

PMID:
27725992
DOI:
10.1007/s00247-016-3721-9
[Indexed for MEDLINE]

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