Role of Nuclear Medicine in Liver Transplantation Ajit N. Shah, Forrest Orthotopic liver transplantation is now a very well- established technique for treating patients with end- stage liver disease. Since 1967, more than 26,000 liver transplants have been performed, including 15,000 in the United States. The overall 1-year survival rate is approximately 80% and 5-year survival is 70%. Nuclear imaging plays an important role in the management of liver transplant recipients before and after liver trans- plantation. The evaluation of candidates potentially includes liver-spleen scan for liver volume, multiple gated acquisition scan, adenosine or stress thallium study, bone scan, and quantitative ventilation perfu- sion scan for hepatopulmonary syndrome. In the post- Dodson, and John Fung transplant phase, the deconvolution analysis (which corrects for the problem of recirculation) is a promis- ing tool for diagnosing rejection, although its role in the transplant population has to be established. A variety of nuclear medicine techniques are helpful in the postoperative diagnosis of biliary complications. By performing a semiquantitative analysis to discrimi- nate hepatocyte dysfunction from biliary disease and measuring hepatocyte extraction fraction by deconvo- lution analysis and excretion, (T1/2 values measured by the nonlinear list squares technique) have been very promising. Copyright 9 1995 by W.B. Saunders Company T HE FIRST orthotopic liver transplantation was attempted in Denver, CO in 1963. Although unsuccessful, these early experiences provided a solid background to which major advances have resulted in routine success. The introduction of cyclosporin, advances in donor surgery and organ preservation, and refinement of surgical technique are a few of these ad- vances. Currently, the longest surviving recipi- ent has survived more than 25 years after transplantation. Since 1967, more than 26,000 liver transplants have been performed world- wide, including more than 15,000 in the United States. Analysis of 5,180 liver transplants in USA (1987 to 1991) shows an overall 1-year survival rate of approximately 80% and a 5-year survival of 70%. 1 The National Institutes of Health Consensus Conference of 1983 established orthotopic liver transplantation as the therapeutic modality of choice for certain end stage liver diseases and since then the indications continue to increase. The indications for orthotopic liver transplanta- tion 2-4 in adults are chronic active hepatitis, s autoimmune hepatitis, primary biiiary cirrhosis, primary sclerosing cholangitis, La6nnec's cirrho- From the Department of Radiology, Division of Nuclear Medicine, and the Department of Surgery, Division of Trans- plantation Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA. Address reprint requests to Ajit N. Shah, MD, Division of Nuclear Medicine, University of Pittsburgh Medical Center, 200 Lothrop St, Pittsburgh, PA 15213. Copyright 9 1995 by W.B. Saunders Company 0001-2998/95/2501-0004505.00/0 sis, fulminant hepatitis, hepatocellular carci- noma in the presence of cirrhosis, Budd-Chiari syndrome, and less commonly metabolic disor- ders, such as Wilson's disease and hemochroma- tosis. Liver transplantation indications in children include biliary atresia or hypoplasia, metabolic disorders such as alpha-1 antitrypsin deficiency, tyrosinemia, glycogen storage disease, type-IV familial hypercholesterolemia, neonatal hepati- tis, fulminant hepatitis, chronic active hepatitis, and familial intrahepatic cholestasis. The absolute contraindications for liver trans- plantation include sepsis outside the hepatobili- ary system; metastatic disease from nonhepatic cancer with exception of apudomas, in which a resection of the primary tumor in conjunction with the transplantation of the liver can be curative; metastatic hepatobiliary malignancy; active alcoholic disease or drug abuse; pulmo- nary hypertension; advanced cardiopulmonary disease; symptomatic acquired immune defi- ciency syndrome; and inability of the patient and/or family to understand the commitment to life-long immunosuppressant therapy. Nuclear medicine imaging potentially can play an important role in the evaluation and management of all organ transplantations, in- cluding liver, kidney, heart, pancreas, and lung. 6 This article addresses only radionuclide studies related to liver transplantation. It is important to know that a wide variety of other modalities, including ultrasound (US), x-ray, computer to- mography (CT), transhepatic cholangiography, and angiography, as well as magnetic resonance 36 Seminars in Nuclear Medicine, Vol XXV, No 1 (January), 1995: pp 36-48