Hepatocellular nodules in liver cirrhosis: contrast-enhanced MR.

Nowadays, the diagnosis of hepatocellular carcinoma (HCC) is increasingly demanded to imaging techniques. Anyway, imaging cirrhotic patients still remains a challenging issue, since pre-neoplastic hepatocellular lesions, as dysplastic nodules (DNs), may frequently mimic small neoplasms. Differently from other imaging modalities, magnetic resonance (MR) can give an accurate evaluation of both intracellular and vascular changes occurring during the carcinogenetic pathway from dysplasia to full malignancy. Both DNs and HCC may in fact show a large variety of signal intensities, strictly reflecting nodules' characteristics, such as lesion architecture, grading, stromal components, as well as intracellular contents. In these last years, the introduction of dedicated contrast media has increased MR diagnostic efficacy, permitting to explore both vascular as well as the pathological changes occurring in the biliary and reticuloendothelial systems during the carcinogenetic process. MR performed with tissue specific contrast agents (hepatobiliary and reticulo-endothelial) may thus give an insight on this "gray area", in whom significant histological changes are already present without an evident nodule arterial supply. This peculiar MR prerogative permits to give predictive information about the evolution trend in a cirrhotic parenchyma and to identify patients at high risk for developing carcinoma who would benefit from well-timed treatments.