Implications of 99mTc-DMSA scintigraphy performed during urinary tract infection in neonates.

Objective: To evaluate prospectively whether normal scintigraphic results during urinary tract infections (UTIs) in neonates were predictive of the absence of dilating vesicoureteral reflux (VUR) (grade > or =III) and permanent renal damage (PRD).

Methods: Term neonates with a first symptomatic, community-acquired UTI participated in the study. Urinary tract ultrasonography and technetium-99m-labeled dimercaptosuccinic acid ((99m)Tc-DMSA) scintigraphy were performed within 72 hours after diagnosis and voiding cystourethrography within 1 to 2 months. DMSA scintigraphy, to determine the development of PRD, was repeated 6 months after UTI.

Results: Seventy-two neonates (144 renal units) were enrolled. Acute pyelonephritis was diagnosed through early DMSA scintigraphy in 19% of renal units, VUR in 22%, and grade > or =III VUR in 13%. The majority (71%) of renal units with grade > or =III VUR had normal early DMSA scintigraphic results. The sensitivity and specificity of abnormal early DMSA scintigraphic results to predict grade > or =III VUR were 29% (95% confidence interval: 11%-55%) and 82% (95% confidence interval: 74%-88%), respectively. PRD was found in 7% of renal units, all of which had abnormal early DMSA scintigraphic results. PRD was significantly more frequent among renal units with grade > or =III VUR than among nonrefluxing renal units (P < .05).

Conclusions: Normal early DMSA scintigraphic results for neonates with symptomatic UTIs were helpful in ruling out later development of PRD but were not predictive of the absence of dilating VUR. To rule out dilating VUR, voiding cystourethrography may be required.