Gd-EOB-DTPA and Yb-EOB-DTPA: two prototypic contrast media for CT detection of liver lesions in dogs.

Abstract

To characterize computed tomographic (CT) attenuation of iodine, gadolinium, and ytterbium in vitro and to study CT liver enhancement after administration of two prototypic hepatocyte-directed contrast media in dogs. Samples with increasing concentrations of iodine, gadolinium, and ytterbium were measured for CT attenuation in a water phantom at tube voltages of 80, 120, and 137 kV. Three groups of five adult beagle dogs each received a 0.5 mmol/kg dose of either gadoxetic acid disodium (gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid [EOB-DTPA]) or Yb-EOB-DTPA as intravenous infusions or Yb-EOB-DTPA as an intravenous bolus injection. At 120 kV, in vitro CT attenuation of gadolinium and ytterbium exceeded that of iodine by 41% and 45%, respectively, when measured at equal mass concentrations (in milligrams per milliliter of saline). In dogs, CT liver enhancement values above the precontrast liver attenuation were 32.6 HU +/- 2.3, 31.4 HU +/- 1.1, and 33.4 HU +/- 5.2 after 0.5 mmol/kg Gd-EOB-DTPA or Yb-EOB-DTPA infusion or Yb-EOB-DTPA bolus, respectively. The values were not significantly different (P > .05) Both Gd-EOB-DTPA and Yb-EOB-DTPA provide excellent CT liver enhancement in dogs. CT liver enhancement is not significantly altered by either the absorbing element (gadolinium vs ytterbium) or the mode of application (infusion vs bolus).