The role of FDG-PET in detecting rejection after liver transplantation

Abstract Background The activation and increased metabolic activity of T cells in acute cellular rejection could allow fluoro-2-deoxyglucose positron emission tomography to be utilized for detection of acute cellular rejection. The objective of this study was to evaluate the effectiveness of fluoro-2-deoxyglucose positron emission tomography in detecting acute cellular rejection in the clinical setting. Methods Fluoro-2-deoxyglucose positron emission tomography studies were performed on 88 orthotopic liver transplant patients at 7 and 17 days postoperatively (first positron emission tomography and second positron emission tomography, respectively). Additional studies were performed if patients had suspicion of rejection and at resolution of rejection (third positron emission tomography and fourth positron emission tomography, respectively). A circular region of interest was placed over the liver for semiquantitative evaluation of fluoro-2-deoxyglucose positron emission tomography images by means of standard uptake values. Results Eighteen of 88 patients in our study (20.5%) had histologically proven acute cellular rejection during a 16 ± 11 day follow-up. There was no significant difference between the standard uptake values of first positron emission tomography among non-rejecters versus rejecters (2.05 ±0.46 non-rejecters versus 1.82 ± 0.40 rejecters, P  = .127). Within the rejection cohort, the standard uptake values from the third positron emission tomography (rejection) were higher compared to the first positron emission tomography (baseline) (2.41 ± 0.48 third positron emission tomography versus 1.82 ± 0.41 first positron emission tomography, P Conclusion Increased signal on fluoro-2-deoxyglucose positron emission tomography over baseline is associated with acute cellular rejection in liver transplant recipients. Additional prospective validation studies are essential to define the role of fluoro-2-deoxyglucose positron emission tomography scan as an early marker for acute cellular rejection.