Comparison of Tc-DMSA Renal SPECT and Ultrasonography for Diagnosis of Acute Pyelonephritis in Children

Received 2/5/2003; revised 6/13/2003; accepted 6/17/2003. For correspondence or reprints contact: Bi-Fang Lee, M.D., Department of Nuclear Medicine, National Cheng Kung University Hospital, 138 Sheng-Li Road, Tainan 704, Taiwan. Tel: (886)6-2766109, Fax: (886)6-2766609, E-mail: [email protected] Introduction: It is often difficult, especially in children, to accurately diagnose acute pyelonephritis (APN) through clinical and laboratory testing. The main goal of this retrospective study was to compare the values of renal ultrasonography (US) and technetium-99m dimercaptosuccinic acid (Tc-DMSA) single photon emission computed tomography (SPECT) in detecting APN in children. Methods: We studied 37 children (26 boys, 11girls; age range, 2 weeks to 9 years; mean, 11 months) with culture-documented febrile urinary tract infection. They were referred consecutively to our department for TcDMSA renal SPECT. The scintigraphic and sonographic results were recorded to evaluate the values of US and Tc-DMSA renal SPECT. The Wilcoxon signed ranks test was performed to analyze the difference in detection rates of the two imaging modalities. Results: Tc-DMSA scans showed changes consistent with APN in 51% (19/37) of the patients. US showed changes consistent with APN in 32% (12/37) of the whole group and in only 47% (9/19) of the patients with scintigraphically documented APN. There is a significant difference (P < 0.05) between the detection rates of these two imaging modalities. Dilatation of the collecting system was noted in 16 patients (43%) by US. Conclusions: Tc-DMSA renal SPECT is a more sensitive method than US in detecting APN. However, US is useful in depicting anatomical abnormalities that may be associated with UTI.