Role OF Geometric Mean in Estimation OF Differential Renal Function in DMSA Scintigraphy

Renal scintigraphy is an imaging method that uses small amount of radioactive materials called radiotracers, a Gamma camera and a computer to evaluate kidney functions and its anatomy.

The relative renal function (RRF), expressed as a percent of total renal function, is important in the initial assessment and treatment of patients having renal diseases. RRF has traditionally been measured by radionuclide renal scintigraphies using different tracers for a long time . Different radiopharmaceuticals such as technetium-99m-diethylenetriaminepentaacetic acid (99mTc-DTPA), technetium-99m-dimercaptosuccinic acid (99mTc-DMSA), technetium-99m-mercaptoacetyltriglycine (99mTc-MAG3).

99mTc-DMSA is a static agent that is actively taken up by the proximal and distal renal tubular cells, directly from the peritubular vessels and accumulates in the renal cortex. Its binding level to protein in mammals is 90% which prevents significant glomerular filtration. DMSA renal scan images provide a good definition of the cortical outline, as well as they show the relative distribution of functional tissue.

Determination of the left to right dimercaptosuccinic acid (DMSA) uptake ratio is theoretically one of the easiest quantitative procedures in nuclear medicine. The quantification can be performed on the posterior view, with or without the lateral view for correction of kidney depth. The geometric mean can also be determined using both the anterior and the posterior views.