Ultrasonic impulse elastography is a technique for studying non-invasive tissue rigidity. In particular, it is used in hepatology to assess the degree of fibrosis in a simple manner, by eliminating, in a number of cases, liver biopsy. The investigation of fibrosis is an essential element in the follow-up of patients with hepatic transplant since it is the indirect sign of a post-transplant complication or a recurrence of the initial disease.