IODIZED-OIL RETENTION WITHIN HEPATIC HEMANGIOMA - CHARACTERISTICS ON IODIZED-OIL CT

Objective: The purpose of this study was to describe the characteristi c computed tomographic (CT) appearance of iodized-oil retention in hep atic hemangioma and to evaluate the duration of the retention of iodiz ed oil on follow-up CT. Methods: Seventeen hepatic hemangiomas of 14 p atients were studied with CT performed 1-3 weeks after injection of 2- 9 mi of iodized oil (iodized-oil CT) for the characterization of focal hepatic lesions, which needed differential diagnosis with hepatocellu lar carcinoma in 10 patients, for therapy in two patients, and for che moembolization therapy of accompanying hepatocellular carcinomas in tw o. Twelve patients had 1-7 follow-up CT scans within an interval of 1- 38 months. Result: In all cases, iodized-oil CT showed iodized-oil ret ention within the tumor, regardless of turner size, shape, location, a nd amount of injected iodized oil. The distribution was incomplete and predominantly peripheral in all cases. Central retention was also see n in seven cases, in which a relatively large amount, of iodized oil w as injected, but retention of iodized oil in the tumor was incomplete even in two cases in which a large amount of iodized oil was injected to relieve symptoms and in three cases in which prominent uptake of su rrounding liver parenchyma was seen. Patterns of retention were predom inantly spotty in five, predominantly nodular in four, and mixed in ei ght patients. Retention materials slowly washed out but persisted for at least 3 months and up to 38 months (mean = 18.1 months), and comple te washout was not seen in any cases at follow-up CT. Conclusion: In a ll cases of hepatic hemangiomas, iodized oil was retained, and retenti on persisted over several months. Distribution and patterns of retenti on were characteristically peripheral: spotty, and nodular at iodized- oil CT. Knowledge of the iodized-oil CT appearance of hepatic hemangio ma would be helpful to interpret follow-up CT studies of patients who have undergone iodized-oil chemoembolization procedures.