A minimum of 8 valid measurements will be obtained for each subject from the right lobe of the liver. The tip of the probe transducer will be covered with coupling gel and placed on the skin, between the ribs at the level of the right lobe of the liver. The operator, assisted by an ultrasonic time motion image, will locate a portion of the liver that is at least 4cm thick and free of large vascular structures. The depth of measurement will be between 25 mm and 65 mm. During the acquisition subjects will lie on their back with the right arm behind the head, in a similar position to that used for liver biopsy. The physician will take the measurements with the probe placed in the intercostal space. The median value of the estimates will be kept as the elasticity value of the liver for a given patient. The entire examination should last approximately 5 minutes.