RADIOLOGY: PANCREAS: Case# 32839: PANC. PSEUDOCYST, FATTY LIVER W/FOCAL FATTY CHANGE. Patient is a 48-year-old female with acute pancreatitis with pseudocyst seen on ultrasound on todays examination. The examination is being requested to evaluate the pancreatic pseudocyst. Non-ionic contrast was used as the patient is currently undergoing asthma therapy. institution. The liver is enlarged with diffuse fatty infiltration with areas of increased fatty infiltration and areas of decreased fatty infiltration. The spleen is normal in appearance without focal lesions evident. The common hepatic duct is visualized and is not dilated. Multiple fluid filled cyst-like structures are seen throughout the pancreas, the largest of which measures 5.0 x 6.0 cm. Fatty infiltration of the liver is one of the most common abnormalities diagnosed on CT of the liver. Fatty change is the response of the liver to various insults such as alcoholism, diabetes, obesity, steroid therapy, and malnutrition. In general, fatty change lowers the attenuation of the liver parenchyma causing hepatic vessels to stand out. While the attenuation of normal liver is equal to or greater than that of normal spleen, liver that has undergone fatty change appears more lucent than normal spleen. Fatty infiltration may involve the liver diffusely, focally, or multifocally. The diffuse pattern is the most common. CT shows decreased attenuation of the entire liver with the vessels standing out prominently following administration of contrast. The liver is usually enlarged. In focal involvement, a fan-shaped area may show fatty change and low attenuation while the rest of the liver appears normal, while in multifocal involvement, there are multiple patchy areas of fatty change which may appear similar to metastases or hepatoma. Fatty infiltration may be differentiated from tumor by the absence of mass effect or vessel displacement, the angulated geometric margins, interdigitating margins with slender fingers of normal or fatty tissue, and the rapid change over time. Fatty change may be seen within 3 weeks following the insult and may resolve within 6 days following removal of the insult.