Position of the Dynamic Renal Scintigraphy with the Furosemide Test in the Diagnosis of ObstructiveUropathies in Childhood

Overview

Administration of a diuretic substance during dynamic renal scintigraphy is widely accepted as a useful testfor differentiation between mechanical obstruction and functional disorders of the upper urinary tract. The papershows the advantages and the pitfalls of thismethod in the diagnosis of subrenal obstruction in the examined groupof patients.54 children (12 girls and 42 boys) aged 3 weeks - 2 years with suspicion of urinary tract obstruction accordingto sonography were examined in 1999 - 2001. Half of them had repeated examinations to evaluate the developmentof obstruction. Dynamic renal scintigraphy using 99mTc-MAG 3 (benzoylmercaptoacetyltriglycrine) was done ona planar Gamma camera MB 9200 (Gamma Budapest) with the patient in a supine position. The amount ofradioactivity administered was calculated according to the tables of EANM (European Association of NuclearMedicine).Furosemide was usually administered intravenously during 15th - 20th minute of the study, of 0.5 mg/kg.Mathematical analysis was performed using the programme Octnucline version 3.3 with semiquantitative estimationof 99mTc-MAG3 blood clearance (tubularmarker) assessing separate function of the kidneys (%) and half-timeof diuretic excretion (min). Marked signs of subrenal obstruction were detected in 10 children (19 %). Subrenal obstruction could not beexcluded in 13 children (24 %). A negative test for obstruction was recorded in 31 children (57 %). The maincontribution of the method are the determination of separate renal function and the evaluation of subrenalobstruction by using the furosemide test. The follow-up static images of the kidneys after the basal investigation isvery helpful in the evaluation of the equivocal findings of obstruction.Conservative treatment predominated in the examined group of patients, especially in children with equivocalfindings of obstruction. Dynamic renal scintigraphy with the furosemide test is very important in the diagnosis ofobstructive uropathies in newborns and infants.

Key words:
dynamic renal scintigraphy using 99mTc-MAG 3, furosemide test, uropathy, childhood