Computed tomography scanning of morris hepatomas with liver-specific polyiodinated triglycerides

Abstract

We compared the computed tomography (CT) scanning characteristics of a polyiodinated triglyceride analog with those of a urographic agent to distinguish Morris-7777 hepatoma (MH) cells from normal hepatocytes in rats. Eighteen Buffalo rats were laparotomized and MH cells injected directly into the hepatic parenchyma or introduced via the portal vein to produce, respectively, focal or diffuse lesions in the liver. Baseline CT scans were obtained 21 days after implantation and prior to intravenous administration of either the polyiodinated triglyceride (45-100 mg I/kg) or the nonionic contrast agent, iohexol (560 mg I/kg). Images were obtained at 0-3 hr and 24 hr. Gross pathologic inspection was performed to validate the imaging results. Hepatomas were nearly isodense with normal liver parenchyma in many of the animals, rendering lesion detection difficult with no contrast agent. The bolus administration of iohexol improved lesion detection in many cases. Lesion conspicuity, however, was significantly improved with the polyiodinated triglyceride at less than one eighth the dose of iohexol. Because of their biochemical nature, polyiodinated triglyceride analogs are specifically cleared by the liver. Consequently, they offer several advantages over nonspecific urographic agents in their ability to enhance lesion conspicuity in this hepatoma model.