Ectopic ureteroceles in infants with prenatal hydronephrosis: use of renal cortical scintigraphy

This study assesses the contribution of renal cortical scintigraphy in the diagnostic evaluation of infants with ectopic ureteroceles.

The records of 20 infants (age range, 3 weeks to 4 months) who were referred for renal cortical scintigraphy after an ectopic ureterocele associated with a duplex kidney was found during follow-up of prenatal hydronephrosis were reviewed retrospectively. All infants underwent voiding cystourethrography, ultrasonography, and Tc-99m DMSA scintigraphy.

All upper moieties showed absent or depressed Tc-99m DMSA uptake. Upper moiety functional impairment was associated with structural abnormalities shown by ultrasonography. The degree of functional impairment was reflective of ultrasonographically defined cortical thickness relative to pelvic diameter, but this relation varied. Eight of 20 (40%) lower moieties had diffusely depressed relative Tc-99m DMSA uptake. Focal defects were also present in three of these eight (38%) lower moieties. Lower moiety functional impairment was associated with higher degrees of pelvic dilatation and with vesicoureteral reflux. Ultrasonography revealed diffuse parenchymal thinning in four of the eight (50%) lower moieties with depressed uptake. Ultrasonography did not define focal parenchymal loss in any lower moiety.

The degree to which function is impaired in the upper moieties of duplex kidneys with ureters terminating in ectopic ureteroceles is not highly predictable by ultrasonography. Lower moiety functional impairment and cortical defects are frequently present in these kidneys and often occur without ultrasonographic evidence of parenchymal damage. Use of renal cortical scintigraphy in the diagnostic evaluation of infants with ectopic ureteroceles is supported.