DMSA Renal Scintigraphy assesses kidney function and displays viable kidney tissue. It is based upon the use of the radioactive tracer, Tc-99m dimercaptosuccinic acid (DMSA). This agent is delivered to the renal cortex and is retained for several hours. This allows measurement of relative left and right renal (kidney) function and is a very sensitive test to indicate the presence of renal scars or active infection in the kidney (pyelonephritis). Renal scars can form following chronic pyelonephritis, often associated with childhood reflux of urine from the bladder to kidney.