Rationale and objectives: The authors investigated whether gadolinium-ethoxybenzyl-DTPA (Gd-EOB-DTPA) can be eliminated in the absence of the two usual excretory pathways (urinary or biliary) and whether a remaining excretory pathway is able to compensate for impaired liver or kidney function.
Methods: The study was performed using two groups of animals: group A animals underwent ligation of the common bile duct, and group B animals underwent ligation of the renal blood vessels. A dose of 0.1 mmol/kg Gd-EOB-DTPA or Gd-DTPA (control) was injected via a tail vein. Bile or urine were collected in fractions of 0 to 1, 1 to 2, 2 to 4, and 4 to 8 hours after administration of either contrast agent. At the end of the experiments, detainment of the contrast agents was determined by measurement of Gd concentrations.
Results: Most of the Gd-EOB-DTPA was rapidly cleared from the body: 89.4% +/- 7.5% of the injected dose within 4 hours after bile duct ligation (group A) and 87.0% +/- 6.0% within 1 hour after ligation of renal vessels (group B). Eight hours after injection of Gd-EOB-DTPA, 3.0% +/- 2.4% of the administered dose of this contrast agent was found in the carcasses of group A animals, and 1.3% +/- 0.6% in carcasses of group B animals. By comparison, at 8 hours after injection, 1.9% +/- 3.2% of the injected Gd-DTPA was found in the carcasses of group A animals (no statistical significant difference as compared with Gd-EOB-DTPA), and 96.3% +/- 3.3% in carcasses of group B animals.
Conclusions: In the rat model, the magnetic resonance imaging contrast agent Gd-EOB-DPTA is rapidly and effectively eliminated by virtue of its dual-elimination pathway. The dysfunction of liver or kidney may be fully compensated by the remaining elimination pathway.