Functional and volumetric assessment of liver segments after portal vein embolization: Differences in hypertrophy response

Background: Patients considered for liver resection with insufficient volume or function of the future remnant liver are candidates for portal vein embolization to allow safe resection. The aim of this study is to analyze the volumetric and functional responses after portal vein embolization and to evaluate predictors of the hypertrophy response. Methods: All patients who underwent portal vein embolization before liver resection 2006-2017 were included. Patients who did not undergo computed tomography–volumetry and functional assessment with technetium-99m mebrofenin hepatobiliary scintigraphy before and after portal vein embolization were excluded. The functional and volumetric response rates were calculated. Multiple regression analysis was conducted to examine the relationship between the hypertrophy response and potential predictors. Results: A total of 90 patients underwent portal vein embolization of the right liver. After 3 weeks, there was a significant increase in both volumetric and functional share of the future remnant liver (both P <.01). The increase in functional share exceeded the increase in volumetric share (P <.01). The median functional contribution of segment 4 after portal vein embolization was 41.5% (31.7%–48.7%) of the nonembolized lobe. Preoperative chemotherapy was not a significant predictor of the increase in function or volume. Compared with benign lesions, malignant diseases were significant negative predictors of the functional response. Conclusion: A total of 3 weeks after portal vein embolization, the functional response exceeded that of the volumetric response, meaning that the waiting time to resection potentially can be decreased. Segment 4 had a significant share of both volume and function, enabling surgical strategies only leaving segment 4 as a monosegment. Neoadjuvant chemotherapy had no negative influence on the hypertrophy response.