ENHANCED MR-IMAGING OF THE LIVER AFTER ETHANOL TREATMENT OF HEPATOCELLULAR-CARCINOMA - EVALUATION OF AREAS OF HYPERPERFUSION ADJACENT TO THE TUMOR

OBJECTIVE. In the arterial phase of dynamic contrast-enhanced MR image s, we observed areas of increased contrast enhancement adjacent to hep atocellular carcinomas treated by percutaneous ethanol injection. The purpose of this study was to assess the frequency, appearance, and loc ation of this hyperperfusion abnormality. it is important not to mista ke this finding for other pathologic conditions. SUBJECTS AND METHODS. Multisection dynamic MR images obtained in 33 consecutive patients wi th hepatocellular carcinoma treated with percutaneous ethanol injectio n were reviewed. Hepatic parenchymal hyperperfusion abnormalities were diagnosed when areas of early enhancement were seen in the hepatic pa renchyma adjacent to the treated tumor. The location, appearance, and frequency of the findings were recorded. RESULTS. Hepatic parenchymal hyperperfusion abnormalities were observed in 15 (45%) of the 33 patie nts on arterial-dominant-phase images. Of these 15 patients, 10 (67%) had MR imaging within 1 month after percutaneous ethanol injection. Hy perperfusion abnormalities were located in liver parenchyma adjacent t o the lesion with wedge shaped appearances. In two patients, early opa cification of the peripheral portal branch was seen within the area of hyperperfusion abnormalities. CONCLUSION. Hepatic hyperperfusion abno rmalities are commonly seen adjacent to a treated hepatocellular carci noma on contrast-enhanced MR images. Awareness of this hyperperfusion abnormality, which is caused by increased blood flow after percutaneou s ethanol injection, is important because such a finding may be misint erpreted as another pathologic condition such as tumor progression or tumor thrombosis of the portal vein branches.