Enhanced MR imaging of the liver after ethanol treatment of hepatocellular carcinoma: evaluation of areas of hyperperfusion adjacent to the tumor.

Abstract

In the arterial phase of dynamic contrast-enhanced MR images, we observed areas of increased contrast enhancement adjacent to hepatocellular carcinomas treated by percutaneous ethanol injection. The purpose of this study was to assess the frequency, appearance, and location of this hyperperfusion abnormality. It is important not to mistake this finding for other pathologic conditions. Multisection dynamic MR images obtained in 33 consecutive patients with hepatocellular carcinoma treated with percutaneous ethanol injection were reviewed. Hepatic parenchymal hyperperfusion abnormalities were diagnosed when areas of early enhancement were seen in the hepatic parenchyma adjacent to the treated tumor. The location, appearance, and frequency of the findings were recorded. Hepatic parenchymal hyperperfusion abnormalities were observed in 15 (45%) of the 33 patients on arterial-dominant-phase images. Of these 15 patients, 10 (67%) had MR imaging within 1 month after percutaneous ethanol injection. Hyperperfusion abnormalities were located in liver parenchyma adjacent to the lesion with wedge-shaped appearances. In two patients, early opacification of the peripheral portal branch was seen within the area of hyperperfusion abnormalities. Hepatic hyperperfusion abnormalities are commonly seen adjacent to a treated hepatocellular carcinoma on contrast-enhanced MR images. Awareness of this hyperperfusion abnormality, which is caused by increased blood flow after percutaneous ethanol injection, is important because such a finding may be misinterpreted as another pathologic condition such as tumor progression or tumor thrombosis of the portal vein branches.