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[email protected] Quantitative Elastography Methods in Liver Disease: Current STATE OF THE ART STATE 1 n Evidence and Future Directions Y r Paul Kennedy, PhD Chronic liver diseases often result in the development of Mathilde Wagner, MD, PhD liver fibrosis and ultimately, cirrhosis. Treatment strat- Laurent Castéra, MD egies and prognosis differ greatly depending on the sever- REVIEWS AND COMMENTA Cheng William Hong, MD ity of liver fibrosis, thus liver fibrosis staging is clinically Curtis L. Johnson, PhD relevant. Traditionally, liver biopsy has been the method Claude B. Sirlin, MD of choice for fibrosis evaluation. Because of liver biopsy Bachir Taouli, MD limitations, noninvasive methods have become a key re- search interest in the field. Elastography enables the non- invasive measurement of tissue mechanical properties Online SA-CME through observation of shear-wave propagation in the See www.rsna.org/education/search/ry tissue of interest. Increasing fibrosis stage is associated Learning Objectives: with increased liver stiffness, providing a discriminatory After reading the article and taking the test, the reader will be feature that can be exploited by elastographic methods. able to: Ultrasonographic (US) and magnetic resonance (MR) im- n Describe the basic principles of elastography methods aging elastographic methods are commercially available, n Describe the current performance of elastography in liver each with their respective strengths and limitations. Here, disease the authors review the technical basis, acquisition tech- n Identify pitfalls and confounders of liver stiffness niques, and results and limitations of US- and MR-based measurements using US and MR imaging elastography techniques.