(99m)Tc-DMSA absolute and relative renal uptake in cats: procedure and normal values

Area of Science:

• Veterinary Nuclear Medicine
• Diagnostic Imaging
• Renal Scintigraphy

Background:

• Accurate assessment of feline kidneys is vital for diagnosing renal diseases.
• 99mTechnetium labelled dimercaptosuccinic acid ((99m)Tc-DMSA) scintigraphy is used for evaluating renal function.
• Technical factors can influence the qualitative and quantitative results of these scans.

Purpose of the Study:

• To investigate the impact of technical factors on feline kidney imaging with (99m)Tc-DMSA.
• To evaluate the influence of positioning, background (BG) correction, and attenuation correction on quantitative uptake values (absolute (AU) and relative (RU)).

Main Methods:

• Eleven healthy adult cats underwent (99m)Tc-DMSA scintigraphy.
• Evaluated positioning (dorsal, ventral, lateral), BG correction, and depth correction (geometric mean and two standards methods).
• Qualitative visual assessment and quantitative analysis of AU and RU were performed.

Main Results:

• Dorsal and ventral positioning improved kidney separation for Region of Interest (ROI) placement compared to lateral views.
• BG correction was essential for accurate AU, preventing systematic overestimation, but did not significantly affect RU.
• Depth correction showed variable effects on RU and resulted in lower AU values when not applied.

Conclusions:

• Optimal positioning (dorsal/ventral) enhances image quality for feline renal scintigraphy.
• Background correction is critical for accurate absolute uptake quantification in (99m)Tc-DMSA studies of feline kidneys.
• Depth correction may be necessary for precise quantitative assessment, particularly for relative uptake values in some cases.