New and improved imaging modalities for NAFLD

Non-invasive detection and quantitative assessment of NAFLD is important as it is associated with obesity, metabolic syndrome and insulin resistance. Differentiation of isolated steatosis (IS) from steatohepatitis (NASH) is critical as a NASH can progress to cirrhosis and develop associated complications such as portal hypertension and hepatocellular carcinoma. Current imaging techniques such as ultrasound and CT are useful for detection and can perform limited quantification of hepatic steatosis. Magnetic resonance imaging (MRI) techniques and MR spectroscopy (MRS) are accurate for fat quantification. Newer imaging techniques are emerging, which can provide more accurate fat quantification and differentiation of subtypes of NAFLD. Proton density fat fraction (PDFF) is an emerging MR based biomarker demonstrating promise for accurate fat quantification. Elastography techniques and in particular, magnetic resonance elastography (MRE) may be able to differentiate IS from NASH, although further studies are needed to confirm. MRI with MRE can provide a one-stop comprehensive evaluation of NAFLD including fat quantification and differentiation of NASH from IS.