[en] The lean meat proportion and longissimus thoracis intramuscular fat percentage were predicted in negative-stress Pietrain pigs by real-time ultrasound using Pie Medical 200. The optimal probing site for the estimation of carcass lean content percentage was first identified. The models for the prediction of carcass lean content proportion by ultrasound measurement were developed. Comparisons between Fat Lean Meter, ultrasonic device Piglog 105 and Pie Medical 200 were made for lean meat proportion estimation in Pietrain carcasses. The intramuscular fat percentage was predicted from the white pixel percentage in the longissimus thoracis ultrasound image