Nephrocalcinosis in premature infants: variability in ultrasound detection

To measure variability among radiologists in the ultrasound diagnosis of nephrocalcinosis in premature infants. In this prospective multicenter study, renal ultrasounds were performed on 54 very low birth weight infants using a 5.0- and 7.5-MHz transducer, and these ultrasounds were read independently by three radiologists. kappa coefficients were calculated to assess variability in identification of nephrocalcinosis among the radiologists. The kappa coefficient (+/- confidence intervals) using a 5.0-MHz transducer was 0.143 (0.108, 0.178); using the 7.5-MHz transducer, the kappa coefficient was 0.268 (0.243, 0.293). All three radiologists agreed in their identification of nephrocalcinosis on 3 of 54 ultrasounds using a 5.0-MHz transducer; a total of 6 of 54 ultrasounds obtained using a 7.5-MHz transducer were read as positive by all three radiologists. There is significant variability among radiologists in the ultrasound identification of nephrocalcinosis in premature infants; a 7.5-MHz ultrasound transducer is associated with less variability in recognizing this lesion.