Differentiation of liver transplantation complications by quantitative analysis of dynamic hepatobiliary scintigraphy

OBJECTIVE: We retrospectively investigated the value of dynamic Tc-diisopropyl-iminodiacetic acid hepatobiliary scintigraphy (HBS) in discriminating postsurgical complications following liver transplantation (LT). METHODS: Dynamic HBS was performed for suspected post-LT complications in 201 cases. Hepatic uptake and excretion was visually graded. The portal perfusion index (PPI) and kinetic parameters were quantitatively analyzed. RESULTS: HBS findings were normal in all 119 (59%) cases without complications. Complications were confirmed in 82 cases: 24 had graft rejection, 48 had biliary obstruction, and 10 had hepatitis. Visual grades of uptake and excretion were abnormal for all three types of complications and showed no discriminative value. The PPI level was significantly higher for grafts with rejection (0.83±0.07) compared with no complication (0.57±0.08), biliary obstruction (0.69±0.06), and hepatitis (0.65±0.07; all P<0.0001). Receiver operating characteristic curve analysis confirmed PPI to be highly accurate for discerning rejection from no rejection (area under the curve, 0.97; sensitivity, 95.8%; specificity, 91.7%) or biliary obstruction (area under the curve, 0.93; sensitivity, 95.8%; specificity, 79.2%). CONCLUSION: PPI measured from dynamic HBS offers a highly accurate method for identifying post-LT rejection and distinguishing it from biliary obstruction or hepatitis.