Diuretic renal scintigraphy in normal dogs

Area of Science:

• Veterinary Radiology
• Nuclear Medicine
• Renal Physiology

Background:

• Diuretic renal scintigraphy is a standard diagnostic tool in human medicine for evaluating pyelectasia.
• Establishing normal physiological parameters in canine subjects is essential for accurate interpretation of renal scintigraphy.
• 99mTc-DTPA (technetium-99m diethylenetriamine pentaacetic acid) is a commonly used radiopharmaceutical for assessing glomerular filtration rate.

Purpose of the Study:

• To determine normal parameters for diuretic renography in healthy adult dogs using 99mTc-DTPA.
• To evaluate the physiological effects of furosemide on canine renal excretion dynamics.
• To establish reference values for key scintigraphic parameters following diuretic administration.

Main Methods:

• 20 healthy adult Mongrel dogs underwent two sessions of 99mTc-DTPA renal scintigraphy.
• In one session, dogs received furosemide (3.0 mg/kg); in the other, they received an equivalent volume of saline as a control.
• Evaluated parameters included glomerular filtration rate (GFR), time-activity curve (TAC) characteristics (time of peak, shape, excretion half-time T1/2), and diuretic effect onset and duration.

Main Results:

• Significant differences in excretion half-time (T1/2) and percentage of maximum activity at 8 minutes were observed between diuretic and saline groups.
• Diuretic renograms showed a steeper decline in TAC post-furosemide compared to the gradual slope in saline controls.
• Median onset of diuretic effect was 1.10 minutes, with a median duration of 0.83 minutes.

Conclusions:

• Furosemide significantly alters renal excretion dynamics in dogs, as evidenced by changes in T1/2 and TAC.
• The study successfully established reference ranges for diuretic renography parameters in healthy dogs.
• These findings provide a basis for differentiating obstructive from non-obstructive pyelectasia in canine patients.