Reappraisal of Tc-99m DMSA scintigraphy for follow up in children with vesicoureteral reflux

We reviewed Tc-99m DMSA scintigraphy in children with vesicoureteral reflux (WR) in order to assess whether repeated Tc-99m DMSA scans are necessary f or the follow up of these patients. Ninety-seven children who were followed up for more than one year (1-7.4 years, average 2.8 years) after the first DMSA scan were included in the study. Fifty-one patients had been diagnose d as primary VUR and 46 as secondary VUR. Age at the first examination rang ed from 0 to 14 years (average 5.1 years). Planar images were taken 2 hours after injection. The % renal uptake per injected dose (%RU) was calculated from posterior images. Kidneys in Il patients (11.3%) changed morphologica lly during the follow up. Of these, new photon deficient areas (PD) were de tected in only 4 patients (4.1%). All of these 4 patients had neurogenic bl adder and were managed with self-catheterization. Of the remaining 7 patien ts, cortical thinning progressed in 5 patients (5.2%) and PDs resolved in 3 patients (3.1%). In one of these 7 patients, PD resolved in one kidney and cortical thinning progressed in the contralateral kidney. Of 97 patients r eviewed, % RU decreased more than 20% during the follow up in 6 patients (6 .2%). All were diagnosed as secondary VUR due to neurogenic bladder. % RU d ecreased only in the contracted kidneys at the initial scan. Two of them un derwent renal transplantation because of severe renal failure. In conclusio n, new PD rarely developed and % RU decreased in only a few patients during the follow up of children with VUR. Repeated Tc-99m DMSA scintigraphy ther efore seems to have little benefit in the follow up of children with VUR. I t should be performed in selected patients with high risk of urinary tract infection or renal failure.