Copper concentration in hyperintense hepatocellular carcinomas of Long-Evans cinnamon rats on T1-weighted images.

The Long-Evans Cinnamon (LEC) rat has abnormal intrahepatic copper accumulation and spontaneously develops hepatocellular carcinomas following hereditary hepatitis. The hepatocellular carcinomas are very similar to human well-differentiated hepatocellular carcinoma in histopathological features and on MR images. Copper is believed to be one of the causes of hyperintensity of hepatocellular carcinomas compared to surrounding non-cancerous tissues on T1-weighted MR image. Eight LEC rats were studied by MR imaging. We measured copper concentrations from the hepatocellular carcinomas and surrounding non-cancerous liver tissues. Signal intensity of hepatocellular carcinomas without cystic areas was iso- to slightly hyperintense relative to surrounding non-cancerous tissues on T1-weighted images. Histopathologically, most of the tumors resembled human highly or well-differentiated hepatocellular carcinomas. Copper concentrations of the hepatocellular carcinomas were lower than the surrounding non-cancerous liver tissues. Copper may not be the cause of increased signal intensity typically observed on T1-weighted images of hepatocellular carcinomas.