Determination of kidney function with 99mTc-DTPA renography using a dual-head camera

Area of Science:

• Nuclear Medicine
• Renal Physiology

Background:

• Single-head gamma camera renography is a long-standing method for estimating kidney function.
• Glomerular filtration rate (GFR) is typically assessed using technetium-diethylenetriaminepentaacetic acid (Tc-DTPA).
• Discrepancies in kidney depth or size can introduce errors in single-head renography due to differing attenuation.

Purpose of the Study:

• To compare the accuracy of single-head versus dual-head gamma camera renography in assessing individual kidney function.
• To evaluate the utility of geometric mean data from dual-head renography in reducing errors associated with kidney depth and size variations.

Main Methods:

• Thirty-four patients underwent both single-head and dual-head renography using Tc-DTPA.
• Single kidney GFR was estimated using both methods (GFRcam1 and GFRcam2).
• Results were compared against GFR determined from plasma samples (GFRps).

Main Results:

• No significant difference was found in the prediction intervals between single-head (GFRcam1) and dual-head (GFRcam2) GFR estimates when compared to plasma-based GFR (GFRps).
• The standard deviations of the differences were 17.6 ml/min for GFRcam1-GFRps and 15.5 ml/min for GFRcam2-GFRps.
• Coefficients of variation were 16.5% for single-head and 14.7% for dual-head estimation.

Conclusions:

• The variance in GFR estimation is comparable between single-head and dual-head renography.
• Dual-head camera renography presents potential benefits for daily practice, offering improved assessment of absolute and relative kidney function.
• This method is particularly advantageous for patients with differential kidney depths or malformed kidneys.