A Study of the sequential relationship between the increase of the future remnant liver volume and the functional transition after preoperative portal vein embolization

Background: Preoperative portal vein embolization (PVE) is a widely used strategy to enable major hepatectomy with insufficient liver remnant. PVE induces hypertrophy of the future remnant liver (FRL) and shift of the functional reserve to FRL. In this study, we investigated the sequential relationship between the increase of the FRL volume and the functional transition after preoperative PVE using 3D fused image of CT and 99mTc-galactosyl-human serum albumin (99mTc-GSA) single-photon emission computed tomography (SPECT). Methods: Thirteen patients who underwent major hepatectomy following PVE were enrolled. CT and 99mTc-GSA SPECT scintigraphy were performed at pre-PVE, one week and two weeks after PVE. Functional Volume (FV) of FRL was defined as total liver volume× (FRL volume counts/ total liver volume counts) of 99mTc-GSA SPECT from 3D fused image with CT. Results: The average increase rate of the volume of FRL and FV of FRL at one week after PVE were 31.7 (16.6) % and 41.2 (31.0) % (mean (SD)) respectively. Those of the volume of FRL and FV of FRL at two weeks after PVE were 43.5 (20.4) % and 52.4 (26.7) % respectively. In three of 13 cases, the FVs were especially lower than CT volumes of FRL at two weeks after PVE. One of the three cases progressed microsteatosis more than 30% by biopsy, and this steatosis improved to 10% 13 weeks after PVE. Conclusions: The functional transition lagged behind the increase of the FRL volume after PVE because of progressing steatosis.