Imaging in pediatric urinary tract infection: a 9-year local experience

Urinary tract infection (UTI) is a common disease entity in children, and a number of imaging options are offered for these patients. The purpose of our study was to retrospectively describe the (99m)Tc-labeled dimer captosuccinic acid (DMSA) renal scintigraphy, ultrasound, and micturating cystourethrography (MCU) findings over a 9-year period.

All children younger than 10 years old who presented to a local hospital in Hong Kong between July 1, 1997, and June 30, 2006, with culture-confirmed UTI and who subsequently underwent DMSA scintigraphy, ultrasound, and MCU were identified. For the purpose of this study, patients with underlying major congenital urinary tract abnormalities were excluded. DMSA scintigraphy was regarded as the gold standard for the diagnosis of renal scarring. DMSA scintigraphy, ultrasound, and MCU findings and clinical outcomes were reviewed and analyzed.

A total of 583 children were included in the study. Of these, 432 children (74.1%) had normal findings on ultrasound and on MCU. Only 13 children (3%) of this group had renal scarring as shown on DMSA scintigraphy. The overall negative predictive value (NPV) for excluding renal scarring of combined ultrasound and MCU reached 97%. The NPV was 97.7% in the subgroup of patients 0 to 2 years old.

For children younger than 2 years with UTI in the absence of underlying major congenital urinary tract abnormalities, we recommend that DMSA scintigraphy may be withheld if findings on both ultrasound and MCU examinations are normal.