Kidney Ultrasonography and Dimercaptosuccinic Acid Scans for Revealing Vesicoureteral Reflux in Children With Pyelonephritis: A 7-Year Prospective Cohort Study of 1500 Pyelonephritic Patients and 2986 Renal Units

Abstract

Background: The presence of vesicoureteral reflux (VUR) has been documented in 1.3% of the general population, 70% of infants with urinary tract infection (UTI), and 15–25% of children with UTI. Objectives: The main aims of this prospective cohort study were to compare the efficiency of different imaging techniques [renal ultrasonography, cortical scintigraphy with technetium-99m dimercaptosuccinic acid (99mTc DMSA)] in detecting VUR in patients with acute pyelonephritis. Patients and Methods: Between June 2003 and March 2010, we recruited a prospective cohort of patients aged 1 month to 14 years. Pediatric patients with documented urinary tract infections and imaging evidence of upper tract involvement were examined by DMSA scintigraphy, renal ultrasonography, and voiding cystourethrography (VCUG). The assessments included UTI profiling, kidney ultrasonography, and DMSA scans. Data were expressed as mean ± SD. Statistical tests were two-tailed and were considered significant when P ≤ 0.05. Results: A total of 1500 pediatric patients were eligible to receive treatment for pyelonephritis. DMSA scans were normal in 20.2% of the patients and abnormal in the remaining 79.8%, and the kidney ultrasonographies yielded normal results in 68.5% of the patients and abnormal results in the remaining 31.5%. There was a significant difference between the ultrasonography reports of patients with normal and abnormal DMSA scans. The VCUG results were normal in 74.1% of the patients and indicated VUR in the remaining 25.9% (VUR grade I in 10.7%, grade II in 7.3%, grade III in 4.7%, grade IV in 1.7%, and grade V in 1.5%). The refluxes were unilateral in 62.9% of the patients and bilateral in the remaining 37.1%. We found a significant correlation between the presence of VUR in VCUG and urological abnormality in ultrasonography (r = 0.14, P < 0.001). The incidence of VUR among patients showing severe abnormalities in DMSA scintigraphy, was significantly higher than that among patients with normal DMSA results or those showing mild to moderate changes in DMSA scintigraphy. Conclusions: We concluded that kidney ultrasonography and DMSA scans can be performed before VCUG in children with UTI. In addition, we recommend performing VCUG in cases of pyelonephritis only when the patients show abnormal kidney ultrasonography or DMSA scan results.