The powerful "lens" of magnetic resonance imaging in the diagnosis of hepatic nodules in patients with cirrhosis: diagnosis of hepatocellular carcinoma without the need of histopathological confirmation - fact!

Radiol Bras. 2017 Jan/Fev;50(1):VII–VIII Chronic liver inflammation, which is responsible for various stages of parenchymal fibrosis and, especially end-stage liver disease (cirrhosis), is the main cause of hepatocarcinogenesis and therefore of hepatocellular carcinoma (HCC), the most common primary malignant neoplasm of the liver. The causes of chronic liver inflammation include not only viral hepatitis but also chronic alcoholism, nonalcoholic steatohepatitis, and several other, less common, conditions. It is extraordinary to realize that with the technological advancement of the devices—mainly those of computed tomography (CT) and, especially, magnetic resonance imaging (MRI), through quantitative techniques and the various types of sequences available—radiologists have powerful noninvasive tools that function as “magnifying glasses” for the indirect study and precise evaluation of the cytoarchitecture of the organs of the body, with special attention to the liver. As detailed and demonstrated by Ramalho et al., in their article published in this issue of Radiologia Brasileira, MRI findings indirectly reproduce histopathological and hemodynamic changes, including altered hepatic morphology, fibrosis, and nodules, the spectrum of which ranges from regenerative nodules to dysplastic nodules of varying grades (from low to high) and, ultimately, HCC. The authors described the various advantages of MRI in relation to CT, including the fact that the former does not involve the use of ionizing radiation, has higher tissue resolution (which can facilitate the identification of intralesional fat components), and allows the use of extracellular and liver-specific contrast agents, as well as an excellent evaluation of the biliary tree by cholangiography. They also demonstrated the superiority of MRI over CT in the diagnosis of small HCCs, as well as in the detection of dysplastic nodules and diffuse HCC. Despite the importance of the abovementioned characteristics in the MRI sequences, the key tool for the diagnosis of HCC— and therefore for the evaluation of nodules in chronic liver diseases— is undoubtedly the study of the hemodynamic behavior against the