Carbon dioxide enhanced ultrasonography of hepatic haemangiomas.

The purpose of this study was to characterize the imaging manifestations of carbon dioxide enhanced ultrasonography (CO2US) in hepatic haemangiomas. CO2US was performed for 52 haemangiomas in 25 patients and for 352 various hepatic nodules in 192 patients. Characteristic enhancement patterns for hepatic haemangiomas were noted. All 39 large haemangiomas (> 1 cm) demonstrated peripheral nodular enhancement in the early and parenchymal phases associated with delayed washout character (> 30 min). Centripetal fill-in of CO2 was noted in 82.1% of large haemangiomas. Two enhancing patterns were noted in 13 small haemangiomas (< 1 cm): peripheral nodular (69.2%) and homogeneous (30.8%). Delayed washout was also noted in all small haemangiomas. Centripetal fill-in of CO2 was hard to define in small haemangiomas. None of the other 352 hepatic nodules had the same imaging features. In conclusion we found that CO2US is valuable in differentiating hepatic haemangiomas from other liver tumours in clinically doubtful cases.