Diffuse fatty liver shows generalized hypodensity of the whole liver on CT, and focal fatty liver shows hypodensity of one or several liver segments. In diffuse fatty liver, the density of the whole liver is reduced under CT scanning, the density of liver is smaller than spleen, the liver/spleen ratio is less than 0.85, and the blood vessels in the liver are not shown due to the reduction of the density of liver, so-called “vascular obliteration sign”. The so-called “vascular obliteration sign” occurs when the density continues to decrease and is smaller than the blood vessels. In focal steatohepatitis, one or more segments of the liver become less dense. Usually diffuse fatty liver is more obvious on imaging and easy to diagnose. Focal fatty liver is often confused with hepatic cavernous hemangioma and hepatic metastases, which can be further diagnosed by MRI if necessary.