It is an open label observation clinical trial, all participants are liver transplant patients. The investigators deem to make a better criteria for assessing liver fibrosis after liver transplantation. The point of the clinical trial is to evaluate the efficacy of multiparameter MRI in the diagnosis of liver fibrosis after liver transplantation.

We collected patients aged 18 to 85 who had undergone liver transplantation. At the same time, all patients underwent liver biopsy or ultrasonic transient elastography after MRI. People who were allergic to gadolinium contrast agent, serious cardiopulmonary disease and contraindications to MRI were excluded.

Inclusion Criteria:

• Subjects aged 18 -85 years
• Patients after liver transplantation
• Patients who are going to undergo liver biopsy or ultrasonic transient elastography
• Patients voluntarily joined the study and signed informed consent

Exclusion Criteria:

• Patients with tumor
• Patients who are allergic to gadolinium contrast agent
• Patients with contraindications to magnetic resonance imaging
• Patients with severe heart and lung diseases
• Patients who are not suitable for this study according to the researcher's judgment.

Patients with liver fibrosis after liver transplantation underwent percutaneous liver biopsy or FibroScan.