DETERMINATION OF THE NORMAL RANGE OF FUROSEMIDE HALF-CLEARANCE TIMES WHEN USING TC-99M MAG3

In radionuclide diuresis renography, furosemide half-clearance times h ave been established using Tc-99m DTPA but have not been verified when Tc-99m MAG3 is used. One hundred and six consecutive diuretic renogra ms using Tc-99m MAG3 for the evaluation of unilateral renal abnormalit ies were assessed. The furosemide half-clearance times of the normal k idneys were all less than 9.8 minutes, with a mean of 3.4 minutes. In 18 patients, the half-clearance times of the normal kidney were artifi cially prolonged because urine had drained before the administration o f the diuretic. The normal furosemide half-clearance time values obtai ned using Tc-99m MAG3 were found to be similar to those established fo r Tc-99m DTPA. Prolonged half-clearance times of Tc-99m MAG3 must be c onfirmed by visual evidence of obstruction.