[Ultrasound in the diagnostics of fatty liver in obesity].
Chronic diffuse liver diseases produce a characteristic ultrasound image called bright liver. On the basis of liver attenuation, two major appearances can be observed: low and high attenuation types. It is proved that high attenuation is associated with fatty liver and subcutaneous fat thickness correlates with attenuation. Cut-off value of attenuation and subcutaneous fat thickness was searched for differentiation of the two attenuation types and that of the normal livers. 441 patients (proved by histology) were examined by ultrasound. 132 normal livers, 176 low and 133 high attenuation type bright livers were found. Cut-off level of attenuation, determined by frequency distribution analysis was defined as 1.1 dB/cm/MHz, between fatty liver and low attenuation type bright liver and normal liver. Cut-off value for subcutaneous fat thickness could not be determined. It is concluded, that above the cut-off point of attenuation, the diagnosis of fatty liver can be established without liver biopsy. Subcutaneous fat thickness values give additive confirmative data.