Nodules in Liver Cirrhosis

Regenerative Nodules Regenerative nodules result from grossly distorted hepatic architecture, heterogeneous regeneration and hepatocellular dysplasia. Cirrhosis can be divided by gross pathology into micronodular, macronodular, and mixed form according to appearances of regenerative nodules. The typical appearance of regenerative nodules on MR images includes isointensity or relatively hyperintensity on T1-weighted images and iso or low signal intensity on T2-weighted images. These appearances may be due to the prolonged T1 and T2 values of fibrous septa, because of infiltration by inflammatory cells and development of pseudo bile ducts in the fibrous septa surrounding the regenerative nodules. Regenerative nodules often accumulate iron more than the surrounding hepatic parenchyma. As gradient-echo MR imaging is particularly susceptible to magnetic field heterogeneity, siderotic regenerative nodules may cause artifactual enlargement of the regenerative nodules with low signal intensity. It is controversial whether the detection of siderotic regenerative nodules at MR imaging should be considered a significant risk factor for HCC. However, pathologic observations suggest a role for iron-accumulated regenerative nodules in carcinogenesis. The findings of studies published in the pathology literature have suggested that the presence of iron in large (> 8mm) regenerative nodules is a significant risk factor for the presence of dysplastic or frank malignant changes.