Liver Stiffness Measurements Using Acoustic Radiation Force Impulse in Recipients of Living-Donor and Deceased-Donor Orthotopic Liver Transplant

Abstract

Objectives: The aim of this study was to evaluate the diagnostic efficiency of the acoustic radiation force impulse (Siemens Medical Solutions, Erlangen, Germany) elastography in assessment of fibrosis in orthotopic liver transplant patients. Materials and Methods:We enrolled 28 orthotopic liver transplant patients (deceased and living donors), whose biopsy decision had been prospectively given clinically. Ten acoustic radiation force impulse elastographic measurements were applied before the biopsy or within 3 days after the biopsy by 2 radiologists. After the core tissue needle biopsy, specimens of all patients were analyzed according to the modified Ishak scoring system. Measurements of acoustic radiation force impulse elastography and pathology specimen results were compared. Key words: Liver biopsy, Liver fibrosis, Metavir, Transient elastography, Ultrasonography IntroductionLiver transplant is the only treatment option for advanced liver disease. However, after liver transplant, acute complications (including primary dysfunction, hepatic artery thrombosis, portal vein thrombosis, hepatic venous obstruction, bile leak, and biliary stricture) or chronic complications (including chronic rejection, disease recurrence, and drug-induced complications) may occur. 1-3 Posttransplant liver dysfunction can have various causes; evaluation of the causes, which can lead to diffuse parenchymal damage, including fibrosis, is of clinical importance.Postoperative B-mode and Doppler ultrasonography (US) are standard procedures for the assessment of graft complications. From US findings, clinical symptoms, and abnormal laboratory findings, a liver biopsy may be required. 4 Although liver biopsy is the standard method for the assessment of morphologic liver changes and fibrosis, it is an invasive procedure that may cause complications. 5 Transient elastography (TE) is currently the most widely used and endorsed method for the asses sment of liver fibrosis in many conditions, such as chronic hepatitis B and C, nonalcoholic steatohepatitis, and nonalcoholic fatty liver disease, as well as in posttransplant patients. 6 Insufficient performance in detecting mild fibrosis, failure to measure liver elasticity in patients with obesity, ascites, and narrow intercostal space, and inability to target liver parenchyma by direct visualization are problems that remain a considerable adversity of this tool. 7,8 Acoustic radiation force impulse (ARFI; Siemens Medical Solutions, Erlangen, Germany) elastography is a new technology to measure liver stiffness and