Pictorial review: sonographic patterns of diffuse and focal fatty infiltration of the liver: differential diagnosis to metastatic liver disease.

Many important articles about fat distribution disorders within the liver have been published in the 1980s and 1990s. However, the diagnostic dilemma of distinguishing diffuse or focal fat distribution disorders especially from malignant neoplasmas persists and is still of clinical relevance. Rare and more common sonographic patterns can be subdivided according to their echogenicity, location, quantity, shape and boundaries by B-mode sonography. The knowledge of the characteristic sonographic patterns of diffuse and focal fat distribution disorders within the liver avoids in most cases costly and more invasive diagnostic procedures. Depending on clinical background in individual cases confirmation of diagnosis of focal fatty liver disease is necessary.