Ultrasound Fails to Delineate Significant Renal Pathology in Children With Urinary Tract Infections: A Case for Dimercapto-Succinic Acid Scintigraphy

Purpose: Routine radiological evaluation in children with urinary tract infections includes ultrasound. Additional dimercapto-succinic acid scintigraphy in this setting is a common but not routine practice to determine whether there is parenchymal injury. Because dimercapto-succinic acid scintigraphy involves further time, expense and radiation, we determined whether ultrasound findings could substitute for dimercapto-succinic acid scintigraphy. Therefore, in children with urinary tract infections we researched the incidence of discordant findings between dimercapto-succinic acid scintigraphy and normal ultrasound. Materials and Methods: A retrospective review of children with a history of urinary tract infections who had normal ultrasound and dimercapto-succinic acid scintigraphy within 6 weeks of each other was performed through a chart review. Children with pyelonephritis within 4 months of the radiological tests were excluded. Dimercapto-succinic acid scintigraphy was considered abnormal if there was less than 40% differential function, global atrophy or focal defects. Results: From January 2005 to December 2006, 100 children met inclusion criteria. Median patient age was 4.5 years (range 4 months to 19 years) and 84% were female. Of the 100 children 74 (74%) demonstrated vesicoureteral reflux and 18 (18%) showed abnormal dimercapto-succinic acid scintigraphy despite normal ultrasound. Children with vesicoureteral reflux showed an increased incidence of abnormal dimercapto-succinic acid scintigraphy compared to those without vesicoureteral reflux (20.3% vs 11.5%), although this did not attain statistical significance (p = 0.04). Conclusions: Although dimercapto-succinic acid scintigraphy is not part of routine practice in all children with urinary tract infections and/or vesicoureteral reflux, it is frequently abnormal despite normal ultrasound. Therefore, dimercapto-succinic acid scintigraphy should be considered in these patients to evaluate cortical defects and possibly guide further management.