Pictorial Review of Hepatic Steatosis on MRI, CT and Ultrasound

Fatty liver disease or hepatic steatosis affects more than three million people in the U.S. every year. It is one of the most common abnormalities of the liver seen on ultrasound, CT and MRI. The most common conditions of hepatic steatosis are alcoholic liver disease and nonalcoholic fatty liver disease. Rare conditions that can cause fatty liver disease include dietary and nutritional abnormalities and congenital disorders. Common patterns of fat deposition in the liver include diffuse fat deposition, focal deposition and focal sparing, multifocal deposition, perivascular deposition and subcapsular deposition. All these patterns involve nonuniform distribution of fat. Diagnosing fatty liver can often be difficult because there are no early signs of clinical symptoms and physical exam findings. Clinical history of alcohol consumption, drug use, hyperlipidemia, obesity, known hepatitis infection and other health conditions can aid in making the diagnosis of fatty liver disease. Ultrasound, CT and MRI can be used to make a diagnosis of fatty liver disease. These imaging modalities can help determine the amount of fat in the liver and the severity of the fatty liver disease. Knowledge of the typical imaging findings of fatty liver disease is important for the radiologist to differentiate from other differential diagnostic conditions.