[Hepatic steatosis: combined echography-computerized tomography imaging].

The authors report their experience with the combined use of US and CT in the study of diffuse and subtotal fatty infiltration of the liver. An apparent disagreement was initially found between the two examinations in the study of fatty infiltration. Fifty-five patients were studied with US and CT of the upper abdomen, as suggested by clinics. US showed normal liver echogenicity in 30 patients and diffuse increased echogenicity (bright liver) in 25 cases. In 5 patients with bright liver, US demonstrated a solitary hypoechoic area, appearing as a "skip area", in the quadrate lobe. In 2 patients with bright liver, the hypoechoic area was seen in the right lobe and exhibited no typical US features of "skip area". Bright liver was quantified by measuring CT density of both liver and spleen. The relative attenuation values of spleen and liver were compared on plain and enhanced CT scans. In 5 cases with a hypoechoic area in the right lobe, CT findings were suggestive of hemangioma. A good correlation was found between bright liver and CT attenuation values, which decrease with increasing fat content of the liver. Moreover, CT attenuation values confirmed US findings in the study of typical "skip areas", by demonstrating normal density--which suggests that CT can characterize normal tissue in atypical "skip areas".