Nephrocalcinosis in premature infants: variability in ultrasound detection

UMMS Affiliation

Department of Pediatrics



Document Type


Medical Subject Headings

Evaluation Studies as Topic; Humans; Infant, Newborn; *Infant, Premature; Nephrocalcinosis; Observer Variation; Prospective Studies




OBJECTIVE: To measure variability among radiologists in the ultrasound diagnosis of nephrocalcinosis in premature infants.

METHODOLOGY: 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.

RESULTS: 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.

CONCLUSION: 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.

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Citation: J Perinatol. 1999 Oct-Nov;19(7):498-500.

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