Non-invasive methods for the diagnosis of nonalcoholicfatty liver disease

Nonalcoholic fatty liver disease （NAFLD） is thecommonest chronic liver disease and includes simplesteatosis and nonalcoholic steatohepatitis （NASH）.Since NASH progresses to cirrhosis more frequentlyand increases liver-related and cardiovascular diseaserisk substantially more than simple steatosis, there is agreat need to differentiate the two entities. Liver biopsyis the gold standard for the diagnosis of NAFLD butits disadvantages, including the risk of complicationsand sampling bias, stress the need for developingalternative diagnostic methods. Accordingly, severalnon-invasive markers have been evaluated for thediagnosis of simple steatosis and NASH, including bothserological indices and imaging methods. The presentreview summarizes the current knowledge on the roleof these markers in the diagnosis of NAFLD. Currentdata suggest that ultrasound and the fibrosis-4 scoreare probably the most appealing methods for detectingsteatosis and for distinguishing NASH from simplesteatosis, respectively, because of their low cost andrelatively high accuracy. However, currently availablemethods, both serologic and imaging, cannot obviatethe need for liver biopsy for diagnosing NASH dueto their substantial false positive and false negativerates. Therefore, the current role of these methods isprobably limited in patients who are unwilling or havecontraindications for undergoing biopsy.