Nonalcoholic fatty liver disease (NAFLD) is currently the most common chronic liver disease, and there has been a rapid increase in cases worldwide. NAFLD is rapidly becoming the leading cause of hepatocellular carcinoma and is also associated with an increased risk of cardiovascular disease or exacerbation of other organ diseases, thus posing a significant health problem from both a medical and a socioeconomic perspective. NAFLD is a systemic disease and requires the involvement of numerous medical professionals. Multidisciplinary collaboration, in which different professionals within different specialties come together and work together toward a common goal, supports better patient care by integrating perspectives of multiple experts and facilitating the exchange of opinions. Due to the large number of potential patients, gastroenterologists and hepatologists cannot manage the patients alone, and collaboration between specialists in various fields, including family doctors, dentists, nutritionists, and pharmacists is required for treatment of NAFLD. This review will discuss NAFLD from the perspective of various specialties and introduce multidisciplinary collaboration.

Non-alcoholic fatty liver disease is currently the most common chronic liver disease, affecting up to 25% of the global population. Simple fatty liver, in which fat is deposited in the liver without fibrosis, has been regarded as a benign disease in the past, but it is now known to be prognostic. In the future, more emphasis should be placed on the quantification of liver fat. Traditionally, fatty liver has been assessed by histological evaluation, which requires an invasive examination; however, technological innovations have made it possible to evaluate fatty liver by non-invasive imaging methods, such as ultrasonography, computed tomography, and magnetic resonance imaging. In addition, quantitative as well as qualitative measurements for the detection of fatty liver have become available. In this review, we summarize the currently used qualitative evaluations of fatty liver and discuss quantitative evaluations that are expected to further develop in the future.