Preoperative Estimation of Future Remnant Liver Function Following Portal Vein Embolization Using Relative Enhancement on Gadoxetic Acid Disodium-Enhanced Magnetic Resonance Imaging

OBJECTIVE: To retrospectively evaluate relative enhancement (RE) in the hepatobiliary phase of gadoxetic acid disodium-enhanced magnetic resonance (MR) imaging as a preoperative estimation of future remnant liver (FRL) function in a patients who underwent portal vein embolization (PVE). MATERIALS AND METHODS: In 53 patients, the correlation between the indocyanine green clearance (ICG-K) and RE imaging was analyzed before hepatectomy (first analysis). Twenty-three of the 53 patients underwent PVE followed by a repeat RE imaging and ICG test before an extended hepatectomy and their results were further analyzed (second analysis). Whole liver function and FRL function were calculated on the MR imaging as follows: RE x total liver volume (RE Index) and FRL-RE x FRL volume (Rem RE Index), respectively. Regarding clinical outcome, posthepatectomy liver failure (PHLF) was evaluated in patients undergoing PVE. RESULTS: Indocyanine green clearance correlated with the RE Index (r = 0.365, p = 0.007), and ICG-K of FRL (ICG-Krem) strongly correlated with the Rem RE Index (r = 0.738, p < 0.001) in the first analysis. Both the ICG-Krem and the Rem RE Index were significantly correlated after PVE (r = 0.508, p = 0.013) at the second analysis. The rate of improvement of the Rem RE Index from before PVE to after PVE was significantly higher than that of ICG-Krem (p = 0.014). Patients with PHLF had a significantly lower Rem RE Index than patients without PHLF (p = 0.023). CONCLUSION: Relative enhancement imaging can be used to estimate FRL function after PVE.