**3. Imaging**

Although histological evaluation of liver biopsies and calculation of values that are based on the determination of serum markers and measurement of body features are extremely helpful to get information on inflammation and fibrosis, these methods have also some limitation. In particular, liver biopsy is invasive, relative costly and associated with relevant biopsy-related complications including bleeding, pain and infections. Moreover, it has been known for decades that the procedure has a high inter-observer variability and may not be representative for the whole organ [101]. In addition, it is impossible to apply liver biopsy to monitor changes in fibrosis stages because this would require multiple repetition of the procedure. Similarly, single or combination of biomarker measurements, which meet all the diagnostic criteria required for widespread, cost-effective, and reliable use are not available. A major pitfall in all these measurements is that the evaluation of any new biomarker is hindered by the lack of reference tests and the inter-technique analytical variability and performance of individual parameters. Therefore, individual biomarkers or multiparametic panels of biomarkers have reached only limited clinical application. Imaging techniques, providing direct information about the health status of the liver, have therefore emerged as attractive alternatives to assess steatosis, steatohepatitis, fibrosis, cirrhosis or hepatic cancer. In the following we will briefly summarize of imaging-based methods for diagnosing NASH and NAFLD.
