UTIs: What’s the best imaging study? ▸

Many radiographic studies are available to evaluate infants with urinary tract infections (UTIs), including ultrasound, voiding cystourethrogram (VCUG), and renal scans, but few well-designed trials have examined the effects of these techniques on management and outcome. As part of a multicenter, randomized trial of different antibiotic regimens, 309 children (age range, 1 to 24 months) who had a first febrile UTI underwent ultrasound and a renal scan within 48 hours of diagnosis, VCUG 1 month later, and a second renal scan 6 months after that.

Ultrasound results were normal in 88% of children, and the identification of abnormalities, including dilated pelvis and pelvocaliectasis, did not lead to changes in management. The initial renal scan demonstrated pyelonephritis in 61% of children. Of 302 children who underwent VCUG, 39% had vesicoureteral reflux (VCR). Of 55 children with grade III or IV VCR, 7 had an abnormal ultrasound. Renal scarring was more likely to have developed in children with VCR (16 of 109 [15%]) than in those without (10 of 166 [6%]).

Comment ▸ The goal of imaging studies in children with UTIs is to identify those at risk for renal parenchymal injury and to preserve renal function. In this study, ultrasound did not contribute to the managment or prediction of VCR. An editorialist (the editor-in-chief of Journal Watch Pediatrics and Adolescent Medicine) states that VCUG remains the most important radiographic study for infants with UTIs. Ultrasound is probably unnecessary, particularly in infants who show no evidence of obstructive lesions of the genital urinary tract on prenatal ultrasonography.

Howard Bauchner, MD

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