Prediction of vesicoureteral reflux in children with febrile urinary tract infection using relative uptake and cortical defect in DMSA scan.

BACKGROUND: Vesicoureteral reflux (VUR) is an important urologic anomaly that causes renal injury in children with febrile urinary tract infection (UTI). The present study aimed to evaluate the associations of abnormalities detected on technetium-99m-labeled dimercaptosuccinic acid (DMSA) scans, focusing on the association with VUR of the levels of relative decrease in kidney function and cortical defects after a first febrile UTI in children.

METHODS: All 171 children underwent ultrasonography, DMSA scan and voiding cystourethrography (VCUG). The features of ultrasound and DMSA scans were compared between patients with (n = 48) and without VUR (n = 123). The relative uptake (RU) by each kidney was derived from the absolute value of the differences between the value for RU of radionuclide in the right kidney and that in the left kidney. The extent of cortical defects (ECD) was graded according to the number of compartments that contained cortical defect in both kidneys (right upper/right lower, left upper/left lower). Receiver operating characteristic curves were constructed to examine the diagnostic value of these parameters of ultrasound and DMSA scans for predicting VUR.

RESULTS: The ratio of patients having hydronephrosis on ultrasound or cortical defects on DMSA scan did not differ significantly between VUR and non-VUR groups. However, the absolute values of the RU and the scores for ECD were significantly higher in the VUR group than in the non-VUR group. The area under the curves for these two parameters were higher than those for the presence of hydronephrosis or the presence of cortical defects or both.

CONCLUSION: Decreased relative function and increased extents of cortical defects on DMSA scan may be associated with the presence of VUR. These findings may assist pediatricians to decide whether febrile UTI children need to undergo VCUG.