The assessment of functional remnant liver rate for the hepatectomy based on the fusion image of 3DCT and 99mTc-GSA SPECT

Abstract

Introduction: Preoperative assessment of future remnant liver (FRL) function is critical for major hepatectomy to avoid postoperative liver failure (PLF).Indocyanine green clearance of the FRL (Krem), which is calculated as the ratio of FRL volume to total liver volume by CT, is reliable index for estimating PLF and its threshold is 0.05. However, Krem assumes homogenous uptake throughout the liver.For damaged livers with functional heterogeneity, fusion images combining 99mTc-GSA SPECT and 3D-CT are helpful to estimate the functional reserve of the FRL. Our aim was to determine the utility of functional Krem (F-Krem) by comparing volumetric Krem (V-Krem). Methods: Between July 2015 to December 2017, 45 patients received preoperative dynamic CT and 99mTc-GSA SPECT and underwent major hepatectomy. We constructed fusion image of 3D-CT and 99mTc-GSA SPECT. V-Krem by CT volumetry and F-Krem by fusion image were compared in each patient to estimate which is more reliable. Results: In 88.9% of the patients, F-Krem was bigger than V-Krem (Figure). The ratio of F-Krem/V-Krem (F/V) was 1.116±0.12 (mean±SD). In the patients with portal vein occlusion (PVO) or large tumor (LT) of 500ml or more, F/V ratio was significantly bigger than that of the other patients: 1.181±0.082 (n=8, PVO)vs.1.097±0.118 (n=37, non-PVO), 1.306±0.174 (n=4,LT)vs.1.11±0.097 (n=41, non-LT), (p=0.01, respectively). There were significantly correlation between F-Krem and postoperative-parameters (T-Bil and platelets counts in POD1,3,7). In 5 patients with V-Krem less than 0.05,a patient had F-Krem more than 0.05, resulting in good post-operative course. Conclusion: In almost patients who need major hepatectomy, F-Krem is bigger than V-Krem, because liver function of the diseased side is impaired compared with residual side. F-Krem is a more reliable index than V-Krem.