Inter- and Intra-observer Reliability of the Urinary Tract Dilation (UTD) Classification System in Neonates: A Multi-Center Study

AbstractPURPOSE:The Urinary Tract Dilation (UTD) classification system was designed to be more objective and reproducible than currently available grading systems. We sought to evaluate reliability and consistency of the UTD system in newborns.METHODS:Of 1046 infants age 0-90 days undergoing ultrasound for hydronephrosis, 243 were randomly selected. Seven readers (4 radiologists and 3 urologists) at four different institutions classified complete, de-identified ultrasound studies on a web-based platform. Inter- and intra-observer agreement was evaluated using Fleiss Kappa statistic.RESULTS:Inter-observer agreement for UTD risk score was moderate among 7 readers (Kappa=0.421 [95%CI: 0.404-0.438]). Inter-observer agreement using the SFU scale was worse than with UTD (Kappa = 0.344 [95%CI: 0.330-0.359]. All 7 readers assigned the same UTD score in 19.3% of cases (47/243). In 38.7% of cases (94/243), at least three readers assigned a UTD score different from that assigned by the other readers. In 7% of cases ...