Evaluation of imaging studies for vesicoureteral reflux in infants with first urinary tract infection

Background: Routine imaging studies following first urinary tract infection(UTI) in infancy are clinically used to identify who has vesicoureteral reflux (VUR) and acute pyelonephritis or renal scars. The potential value of these images in avoiding children acquiring renal complication and whether the children benefited from these examinations were not well justified. Methods: Analysis was undertaken of 114 infants (228 renal units) at the time of first documented UTI. All underwent renal ultrasound, voiding cystourethrography (VCUG) and dimercaptosuccinic acid (DMSA) renal scan on admission and repeated follow-up VCUG, DMSA or both after 4-6 months if initial examinations showed abnormal at first time. The VUR on VCUG when UTI and its statistical correlations with both acute and follow-up DMSA renal scan revealing renal scar were calculated. Results: Seventeen children (14.9%) had VUR detected by VCUG. Forty-six patients (40.4%) had abnormal findings on acute DMSA renal scans (acute pyelonephritis or renal scars). The sensitivity, specificity, positive prediction rate and negative prediction rates of DMSA for VUR were 63%, 82. 6%, 32.7% and 94.3%, respectively. The initial identified VUR versus renal scarring on follow-up DMSA showed little correlation. Conclusions: There is limited effectiveness of routine investigation by VCUG in infants with first confirmed UTI. VCUG may be withheld in a child who presents with first UTI before the age of one year if there has been no demonstrable abnormal DMSA scan.