CT urograms in pediatric patients with ureteral calculi: do adult criteria work?

Background: Secondary signs of urinary obstruction associated with ureteral calculi are useful adjuncts to diagnosis in adults with renal colic evaluated by unenhanced helical CT.
Objective: Our purpose was to evaluate the frequency of secondary signs of obstruction in children with renal colic undergoing unenhanced helical CT.
Materials and Methods: Ureteral calculi were identified in 20 of 61 children with acute flank pain examined by unenhanced helical CT. Each imaging study was evaluated for the presence of secondary signs of urinary obstruction. The frequencies of individual signs were compared with each other by means of the McNemar test.
Results: Six children had no secondary sign identified. In the remaining 14 children, proximal ureteral dilatation was seen in 10, renal enlargement in 10, hydronephrosis in 9, tissue rim sign in 6, decreased kidney attenuation in 5, and perinephric stranding in 1. Comparison of the frequencies strongly suggested that perinephric stranding occurs less frequently than proximal ureteral dilatation (P = 0.004), hydronephrosis (P = 0.008), or renal enlargement (P = 0.012).
Conclusion: Perinephric stranding, a common secondary sign in adults with ureteral calculi, occurs less frequently in children than other reported secondary signs.