In this study, we have first described the normal liver structure including the hepatic acinus that is characterized by its structural and functional heterogeneity. Second, we have addressed the pathogenesis of liver fibrosis: the major source of excess extracellular matrix appears to be perisinusoidal stellate cells. The concept of reversibility of liver fibrosis opens the way for new therapeutic perspectives. We have then analyzed the different methods of assessment of liver fibrosis. Liver biopsy is the current reference standard. However, it is invasive and subject to sampling error. Consequently, many attempts are made to develop non-invasive tests: biochemical tests and imaging methods, including functional MR imaging with perfusion, diffusion or spectroscopy, have been proposed. Among the imaging methods, elastography by measuring directly the liver stiffness appears as one of the most promising techniques. Lastly, we have described our research that was focused on MR elastography. Our results show that MR elastography is a feasible, accurate and reproducible method to stage liver fibrosis, and that it is superior to biochemical testing with aspartate-to-platelets ratio index and ultrasound elastography to stage liver fibrosis. Further studies remain to be done to decrease the long examination time of MR elastography and, consequently, to integrate it into a comprehensive hepatic MR protocol.