99mTc-MAG3 diuretic renography in children: a comparison between F0 and F+20

The aim of this work was to compare the quality of renal drainage obtained with two well-described procedures of diuretic renography (F+20 and F0 tests). We selected 36 clinically stable children, aged 10 days to 17 years, with unilateral (25) or bilateral (11) hydronephrosis, in whom both F+20 and F0 tests were successively performed. In all cases, a late image (PM) was acquired after micturition and after changing the position of the patient. The following parameters were calculated: the time to the maximum of the basic renogram (Tmax); and the normalized residual activity (NORA) and output efficiency (OE) at the end of the 20 min renogram, at the end of the furosemide test (35 min) and on the PM image. In F+20, the renal drainage was better on the PM image than at the end of the diuretic renogram, whereas, in F0, the renal drainage was better on the PM image than at the end of the 20 min diuretic renogram. When comparing F0 and F+20, both OE and NORA parameters revealed slightly better drainage at the end of the 20 min F0 renogram than at the end of the 35 min F+20 diuretic renogram. The drainage obtained on the late post-voiding image was comparable for both F0 and F+20 tests. In conclusion, the quality of drainage obtained during the F+20 and F0 procedures can easily be compared using both OE and NORA. A very similar quality of drainage was reached for both procedures when considering only the PM image. This PM view remains mandatory irrespective of the timing of the furosemide injection and despite the use of tracers with a high extraction rate.