[Parametric representation of kidney function using 99mTc-mercaptoacetyltriglycine (MAG3)].

Area of Science:

• Nuclear Medicine
• Radiopharmacology
• Renal Physiology

Background:

• 99mTc-mercaptoacetyltriglycine (MAG3) is a novel radiotracer for assessing kidney function.
• Lower radiation dose of MAG3 allows higher administered activity and improved counting statistics compared to 131I-ortho-iodo-hippurate (OIH).
• This facilitates advanced applications like parametric imaging of renal function.

Purpose of the Study:

• To compare the kinetics of MAG3 with the established tracer OIH in patients.
• To evaluate the utility of MAG3 for quantitative regional renal function assessment using parametric imaging.

Main Methods:

• Comparative kinetic study of MAG3 and OIH in 38 patients.
• Analysis of extrarenal and intrarenal tracer kinetics using deconvolution analysis.
• Generation of parametric images (perfusion, uptake, extraction, transport time) from MAG3 pixel-renograms.

Main Results:

• Good correlation observed between MAG3 and OIH for extrarenal kinetic parameters (distribution volumes, elimination times).
• MAG3 clearance rates were consistently lower than OIH.
• High correlation found for intrarenal kinetic parameters (amplitude, extraction fraction, mean transport time).
• Parametric images revealed characteristic alterations in various renal disorders, including renal artery stenosis and acute tubular necrosis.

Conclusions:

• MAG3 is a suitable tracer for parametric imaging of kidney function.
• Parametric imaging with MAG3 provides quantitative insights into regional renal function.
• This technique aids in the diagnosis and assessment of diverse renal pathologies.