American Journal of Roentgenology, Vol 167, 897-900, Copyright © 1996 by American Roentgen Ray Society
Antenatal renal pelvis dilatation: a predictor of vesicoureteral reflux?
G Walsh and PA Dubbins
Department of Diagnostic Imaging, Derriford Hospital, Plymouth, United Kingdom.
OBJECTIVE: The purpose of our study was to evaluate the role of antenatally
diagnosed renal pelvis dilatation (RPD) as a predictor of vesicoureteral
reflux (VUR) in infants. SUBJECTS AND METHODS: All cases of RPD (i.e.,
those with a renal pelvis diameter equal to or greater than 5 mm) detected
on routine antenatal sonography at our institution over a 3-year period
were followed throughout infancy with serial sonographic evaluation.
Infants with moderate to severe RPD on the initial postnatal study (i.e.,
those with a renal pelvis diameter greater than 15 mm) were further
evaluated with voiding cystography or nuclear scintigraphy
(99mTc-2,3-dimercaptosuccinic acid or 99mTc-
benzoylmercaptoacetyltriglycerine). We have now reviewed all postnatal
imaging on these infants. In addition, the records of all infants who
presented to our institution with clinically symptomatic VUR during this
same period have been retrieved. Antenatal sonograms were available for
review in most of these cases. RESULTS: Seventy-six cases of RPD were
detected on antenatal sonography at our institution over a 3-year period.
Eight cases were lost to follow-up in early infancy. The remaining 68
infants had serial sonography performed throughout infancy. Twenty-five
infants showed no evidence of urinary tract dilatation on postnatal
sonography. Extrarenal pelves were present in eight cases, and 35 infants
had moderate to severe RPD at 72 hr. On further evaluation of this last
group with voiding cystography or nuclear scintigraphy, diagnoses were VUR
(n = 6), pelvic-ureteric junction obstruction (n = 5), renal dysplasia (n =
1), and congenital megaureter (n = 1). VUR was detected in five male
infants and one female infant. Twenty-two infants with moderate to severe
RPD had neither an obstructive uropathy nor VUR. During this same period
(July 1988-June 1991), 20 cases of VUR were detected at our institution.
Antenatal sonograms were available for review in 16 of these cases. These
showed evidence of RPD in five fetuses, whereas the remaining 11 antenatal
studies were unremarkable. Our results show the positive predictive value
of RPD for VUR to be 17%. CONCLUSION: Antenatally detected RPD, in
isolation, is a weak predictor of VUR. Postnatal sonographic evaluation is,
however, important in this group. Further investigation of infants showing
moderate to severe RPD in the neonatal period is merited, as such
investigation will lead to early detection of VUR in a significant number
of cases (17% of RPD).