Combined hepatocyte-selective and blood-pool contrast agents for the CT detection of experimental liver tumors in rabbits

PURPOSE: To determine the imaging characteristics of a new computed tomogra phic (CT) contrast material with both hepatocyte-selective and blood-pool c omponents (iodinated triglyceride (ITG)-dual) versus standard iohexol. MATERIALS AND METHODS: VX2 carcinoma was inoculated in seven rabbits. Anima ls underwent nonenhanced, iohexol-enhanced (600 mg of iodine per kilogram o f body weight), and ITG-dual-enhanced (blood-pool moiety, 100 mg of iodine per kilogram; hepatocyte-selective moiety, 100 or 200 mg of iodine per kilo gram, injected 90 minutes apart) helical CT. Livers were removed, preserved in formalin, suspended in agar, and sectioned transversely at 3-mm interva ls. Attenuation values for normal liver and tumors were obtained, and blind ed readers evaluated images for lesions by using a modified free-response r eceiver operating characteristic (ROC) method. RESULTS: A total of 47 separate tumor sites were detected at pathologic exa mination. ITG-dual-enhanced scans obtained with 300 mg of iodine per kilogr am demonstrated similar liver opacification to iohexol-enhanced scans obtai ned with 600 mg of iodine per kilogram, but with less lesion enhancement, w hich resulted in better liver-to-lesion contrast. Blinded readers had a hig her sensitivity, accuracy, and area under the ROC curve for ITG-dual-enhanc ed scans as compared with iohexol-enhanced scans (P < .01). CONCLUSION: ITG-dual-enhanced CT quantitatively and qualitatively improved liver lesion detection versus iohexol-enhanced CT. Future clinical trials w ith various human tumor types after potential approval for human use are ne eded to determine the ultimate role of this or other dual-mechanism contras t materials.