Glomerular filtration rate estimation by gamma camera technique using various methods of kidney depth measurement: A...

Area of Science:

• Nuclear Medicine
• Renal Physiology
• Medical Imaging

Background:

• Renal scintigraphy with [99mTc]Tc-DTPA Gates' protocol is standard for glomerular filtration rate (GFR) estimation.
• Accuracy of GFR estimation is highly dependent on renal depth measurement techniques.
• This study compares three depth correction methods against plasma sample analysis.

Purpose of the Study:

• To systematically compare GFR estimation using Gates' protocol with three different renal depth estimation techniques.
• To evaluate the accuracy and reliability of Tonnesen formula, lateral depth, and CT scan methods for GFR calculation.
• To identify the most accurate method for renal depth correction in GFR estimation.

Main Methods:

• [99mTc]Tc-DTPA renal scintigraphy performed on 40 voluntary renal donors.
• Renal depth measured using Tonnesen formula, lateral depth, and CT scan.
• GFR calculated via Gates' protocol and compared with gold standard double plasma sample analysis.

Main Results:

• All three methods showed statistically significant variations from plasma sample-derived GFR.
• Tonnesen formula demonstrated the closest agreement (ICC=0.759) but tended to underestimate GFR.
• Lateral depth and CT scan methods overestimated GFR, with varying degrees of correlation and agreement.

Conclusions:

• The choice of renal depth estimation technique significantly impacts GFR accuracy in Gates' protocol.
• The Tonnesen formula, despite underestimation, offers better agreement compared to lateral depth and CT scan methods.
• Further refinement of depth correction techniques is necessary for precise GFR determination.