HCC diagnosis with liver-specific MRI--close to histopathology.

Thanks to the sensible and continuous improvements achieved, magnetic resonance imaging (MRI) can nowadays be considered the most accurate modality to image the liver. Moreover, the technique is the only one able to provide at the same time information about intracellular and vascular changes occurring in parenchymas. For these reasons, MRI plays a major role in the surveillance and follow-up of patients with cirrhosis. If a baseline MR study investigates the progressive alteration of lesion architecture, grading, stromal component, as well as intracellular content of fat, glycogen, or metal ions, thus leading to a frequent confident diagnosis of lesion nature, a dynamic study provides additional information about lesion vascular enhancement, which may represent the only clue for the differential diagnosis between premalignant and malignant lesions. In addition, the introduction of hepatobiliary contrast agents has further implemented the diagnostic confidence of the technique, permitting to explore the so-called grey area in which significant histological changes are already present without an evident arterial supply of the nodule. Although in the evaluation of liver pathologies MRI is mainly applied in the study of cirrhosis, the technique also plays a fundamental role in the assessment of other primitive liver malignancies, such as fibrolamellar carcinoma or cholangiocarcinoma. In these cases in particular, MRI is required to pose a differential diagnosis with other liver malignancies (such as metastases), and, once the nature of the neoplasm is assessed, to give an accurate locoregional staging. Copyright 2009 S. Karger AG, Basel.