Renal Cortical Agents

While MAG-3 and to a lesser extent DTPA provide some visualization of the renal parenchyma, we need radiotracers that bind to the renal tubules for adequate cortical visualization. Two such agents are available: DMSA and glucoheptonate, both of which are bound to ^99mTc.

DMSA binds to the cortex better and provides greater activity, allowing better resolution of cortical defects, making it the preferred agent in small infants. The renal cortical exposure is about the same for DMSA and glucoheptonate, but DMSA provides lower gonadal and bladder exposure.

Renal cortical imaging is very sensitive for the diagnosis of renal parenchymal infection and is the imaging procedure of choice when there is an uncertain diagnosis of acute pyelonephritis in children. Acute pyelonephritis may present as a focal defect, multiple defects, or diffusely decreased uptake. Defects are also seen in areas of cortical scarring.

	DMSA	Glucoheptonate
Kinetics	40% concentrated in tubules by 6 hours and remainder excreted slowly.	Filtration and tubular excretion.
Renal function estimate	None	Early images can be used to assess renal perfusion
Ureters and bladder	-	+
Imaging	Immediate and 2-4 hours. Longer if impaired renal function.	Immediate.
Disadvantages	Short shelf-life.
Dose-limiting organ	Kidneys.	Bladder.
Dose	37-185 MBq (1-5 mCi)	370-740 MBq (10-20 mCi)

References

• Mettler FA and Guiberteau MJ. Chapter 10. In Essentials of Nuclear Medicine Imaging. Fifth Edition. Saunders, Philadelphia. 2006. pp 294-295.
• Mandell GA, et al. Society of Nuclear Medicine Procedure Guideline for Renal Cortical Scintigraphy in Children.