99mTc-MAG–3 Renogram Normal Values
Furosemide Half Time
No Obstruction = < 10 min
This value is defined as the time it takes the kidney to excrete the radiotracer starting at the peak in the renogram -and that is taken as 100%- to reach 50% of that value. Usually the diuretic is given intravenously at min 15 (T15). Half time values higher than 20 min are considered clearly prolonged and correlate to obstructive pattern. Those between 10 min and 20 min are indeterminate and should be interpreted taking into consideration the complete clinical picture (See illustrative renographic curves).
References:
1 Rossleigh MA et al. Determination of the normal range of furosemide half-clearance times when using Tc-99m MAG3. Clin Nucl Med. 1994 Oct;19(10):880-2.