COMPARISON OF GADOLINIUM CY(2)DOTA, A NEW HEPATOBILIARY AGENT, AND GADOLINIUM HP-DO3A, AN EXTRACELLULAR AGENT, IN HEALTHY LIVER AND METASTATIC DISEASE

RATIONALE AND OBJECTIVES. A new gadolinium (Gd) chelate with preferent ial hepatobiliary uptake, Gd Cy(2)DOTA, was compared in two animal spe cies with Gd HP-DO3A (gadoteridol), a clinically approved contrast age nt with extracellular distribution. Liver enhancement was evaluated fo r these two contrast agents using magnetic resonance imaging, whereas an experimental model of metastatic disease was used to evaluate the a gents' efficacy for liver-lesion delineation. METHODS. The two agents were compared in four healthy Rhesus monkeys (eight studies) and five New Zealand White rabbits with implanted VX-2 liver tumors (ten studie s). The contrast dose was 0.1 mmol/kg, with the agents given in random order and at least 72 hours between contrast injections. Breathhold T 1-weighted spin echo scans were obtained at 1.5 tesla (T) before and a fter contrast was administered. Postcontrast scans were obtained I to 90 minutes after injection in the monkeys and I to 240 minutes after i njection in the rabbits. RESULTS. Prolonged hepatic enhancement, super ior in degree to that with Gd HP-DO3A, was noted in both monkeys and r abbits after injection of Gd Cy(2)DOTA. Two minutes after contrast, li ver SI was 1.94 +/- 0.05 with Gd Cy(2)DOTA compared with 1.51 +/- 0.05 with Gd HP-DO3A in monkeys. Sixty minutes after contrast, liver SI wa s 1.60 +/- 0.09 compared with 1.20 +/- 0.02. The difference between ag ents was significant at all times from 2 to 60 minutes after contrast injection (P < 0.01). Excretion of contrast into the gall bladder was observed in both animal species with Gd Cy(2)DOTA but not with Gd HP-D O3A. The maximum improvement in lesion conspicuity (rabbit) occurred 4 5 minutes after injection of Gd Cy(2)DOTA and 5 minutes after injectio n of Gd HP-DO3A. Sixty minutes after injection, liver-lesion contrast was 246 +/- 61 with Gd Cy(2)DOTA and 106 +/- 28 with Gd HP-DO3A, with a significant difference (P < 0.02). CONCLUSIONS. Gd Cy(2)DOTA provide s greater enhancement of the liver parenchyma on immediate and delayed magnetic resonance scans than does Gd HP-DO3A. On delayed scans, Gd C y(2)DOTA provides superior delineation of metastatic liver lesions.