Computed tomography of the liver in rhesus monkeys following losefamate meglumine administration.

Iosefamate meglumine was evaluated for potential use as a contrast agent for hepatic computed tomography (CT) in rhesus monkeys. Iosefamate meglumine in doses of 150, 300, and 450 mg I/kg was injected into four rhesus monkeys and hepatic CT attenuation values, blood iodine levels, serum enzyme levels, and hepatic histology were monitored. The hepatic CT number increased by 19 to 30 HU following a 150 mg I/kg dose and remained elevated for 15 to 45 minutes. Peak blood iodine values occurred 2 minutes postinjection but fell rapidly to less than 40% of the peak value by 45 minutes and less than 20% of peak by 4 hours. Transient elevations in serum enzyme levels were found but no histologic abnormalities were detected. Iosefamate meglumine is a potentially valuable hepatic CT contrast agent, as it produces a significant, prolonged increase in hepatic attenuation values and selectively opacifies functioning hepatocytes.