ELIMINATION OF GADOLINIUM-ETHOXYBENZYL-DTPA IN A RAT MODEL OF SEVERELY IMPAIRED LIVER AND KIDNEY EXCRETORY FUNCTION - AN EXPERIMENTAL-STUDYIN RATS

RATIONALE AND OBJECTIVES. The authors investigated whether gadolinium- ethoxybenzyl-DTPA (Gd-EOB-DTPA) can be eliminated in the absence of th e two usual excretory pathways (urinary or biliary) and whether a rema ining excretory pathway is able to compensate for impaired liver or ki dney function. METHODS. The study was performed using two groups of an imals: 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 ta il 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 i njected 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). E ight hours after injection of Gd-EOB-DTPA, 3.0% +/- 2.4% of the admini stered 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 comp arison, at 8 hours after injection, 1.9% +/- 3.2% of the injected Gd-D TPA was found in the carcasses of group A animals (no statistical sign ificant difference as compared with Gd-EOB-DTPA), and 96.3% +/- 3.3% i n carcasses of group B animals. CONCLUSIONS. In the rat model, the mag netic resonance imaging contrast agent Gd-EOB-DTPA is rapidly and effe ctively eliminated by virtue of its dual-elimination pathway. The dysf unction of liver or kidney may be fully compensated by the remaining e limination pathway.