Comparison of three different diuretic renal scintigraphy protocols in patients with dilated upper urinary tracts

PURPOSE: To compare 3 different diuretic renal scintigraphy protocols in patients with dilated upper urinary tract. MATERIALS AND METHODS: Three diuresis renography protocols were performed in 22 adult patients (28 kidneys) with upper urinary tract dilatation. The diuretic was given 20 minutes after (F+20), at the same time as (F+0), and 15 minutes before (F-15) radionuclide administration. The mean age was 29.8 years (range, 18-43 years). The 3 protocols were identical, except for the time of injection of furosemide. The F+0 protocol could not be performed in 1 and F-15 in 2 of the patients. Each of the 3 protocols was performed for the rest of the patients. The results were classified as nonobstructive, equivocal, and obstructive according to the renogram images and curves. RESULTS: None of the patients showed equivocal results in both F+0 and F-15 protocols. In the F+20 studies, 7 of the 28 kidneys were evaluated as equivocal. Of these, 5 kidneys showed nonobstructive and 2 kidneys revealed obstructive renogram patterns with the other 2 protocols (F+0 and F-15). Moreover, one kidney, which was evaluated as nonobstructive in the F+20 protocol, showed an obstructive pattern in both F+0 and F-15 protocols. All of the kidneys showing obstructive patterns in the F+20 study also revealed obstruction in the F+0 and F-15 investigations. We could not find any difference between the renogram patterns of F+0 and F-15 investigations. CONCLUSIONS: F+0 and F-15 protocols allow clarification in cases of equivocal F+20 studies. Because the F+0 study is more practical and shorter, we suggest the F+0 method when equivocal results are obtained by an F+20 study or as a single test when there is only one opportunity to confirm or exclude the presence of obstruction.