The basics of renal imaging and function studies.

Abstract

Many radiotracers are available for kidney studies. They are classified into glomerular tracers (DTPA, EDTA), tubular tracers (OIH, MAG3) and cortical tracers (DMSA, GHA). Renal function is best assessed by glomerular filtration rate. Camera studies provide a relative function assessment, whereas clearance techniques provide a precise and reliable assessment of absolute renal function. The combination of both therefore gives a comprehensive study of glomerular function. Attempts to assess absolute function from camera studies only resulted in gross inaccuracy. Tubular tracers have a higher extraction rate. This could be used to estimate renal plasma flow (by assessing the effective renal plasma flow), or to determine relative function when renal function is low, or to study the urine flow in the urinary tract. Cortical tracers provide a high imaging quality. They are more adapted to infection assessment and relative function measurements. This paper reviews the most commonly used tracers and their relationship with renal physiology. Techniques for camera static and dynamic studies and plasma and urinary clearances are detailed. Procedures follow the recommendations of the most recent international consensus conferences on the topics.