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In order to evaluate CT findings with time and to confirm the capsular structure correlating with its histopathologic findings, we experimentally induced ischemic necrosis of liver in 20 rabbits. Incision of the abdomen was performed under anesthesia. Ligation of hepatic artery, portal vein and hepatic duct of right inferior posterior lobe of the liver after injection of macroaggregated albumin into right inferior posterior portal vein in order to prevent from developing collateral circulation as possible. Precontrast and postcontrast enhanced CT images were obtained at 1. 2. 4 days and 1, 2. 4. 6 weeks after induction of ischemic necrosis. Necrotic area in the liver showed homogeneous low density compared to normal liver, and no contrast enhancement after contrast material administration, and marked volume loss with time. CT attenuation value of necrotic area at 1 day(36.7±6.4 M±SD, Hounsfield unit) approached to two third of that of normal liver(56.3±7.3) and showed no significant change until two weeks but increased significantly after four weeks. On contrast enhanced CT images, capsular structure was obsereved as a high density rim along the liver surface of the necortic area in 8 of 15 cases. From the first day on, homogenous ischemic or coagulation necrosis was observed but rarely findings of edema, hemorrhage and cystic change were observed on histopathologic specimen. In all of the histologic samples taken from 10 cases during th 2nd to 6th week, fibrous thickening with rich vascularity was observed along the surface of the necrotic area. In conclusion, ischemic necrosis of the liver showed homogeneous low density and no contrast enhancement. CT attenuation value of necrotic area increased significantly with time associated with markedly decrease in volume. Capsular structure attributed to the hypertrophy of the liver capsule and rich vascularity within it.
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