A COMPARISON OF 2 MR HEPATOBILIARY GADOLINIUM CHELATES - GD-BOPTA ANDGD-EOB-DTPA

Purpose: Two gadolinium chelates with partial hepatobiliary excretion, Gd-BOPTA and Gd-EOB-DTPA, and one gadolinium chelate with exclusively renal excretion, Gd-HP-DO3A, were compared on MRI at 1.5 T. The time course of enhancement for normal liver, gallbladder, spleen, kidney, a nd muscle was specifically examined in the rhesus monkey. Method: Four animals were evaluated with each agent for a total of 12 MR studies. Breath-hold and non-breath-hold T1-weighted scans were acquired prior to and 1, 2, 3, 4, 5, 15, 30, 45, 60, 75, and 90 min after intravenous contrast medium injection. The same contrast dose, 0.1 mmol/kg, was u sed for all studies. Images were analyzed by region-of-interest measur ements. Results: Both hepatobiliary gadolinium chelates achieved susta ined enhancement of normal liver parenchyma, superior in magnitude to that following Gd-HP-DO3A injection. On scans 45-90 min following inje ction, liver enhancement with Gd-BOPTA was superior to that with Gd-EO B-DTPA. This difference was, however, not statistically significant. L iver enhancement decreased more rapidly on delayed scans with Gd-EOB-D TPA than with Gd-BOPTA, a result that was statistically significant. E xcretion of contrast agent into the gallbladder was noted with both he patobiliary agents but not with Gd-HP-DO3A. Conclusion: Enhancement of normal liver parenchyma peaks at a later time after injection with Gd -BOPTA than with Gd-EOB-DTPA. However, the maximum percent enhancement is comparable when (as in the current evaluation) the two agents are compared at the same dose (0.1 mmol/kg). This finding supports the cho ice of optimal imaging time post contrast agent administration (for de layed scans) in clinical trials of 20-45 min post injection with Gd-EO B-DTPA and 60-120 min post injection with Gd-BOPTA.