99mTc-mebrofenin hepatobiliary scintigraphy and volume metrics before liver preparation: correlations and discrepancies in non-cirrhotic patients

Background: Accurate identification of insufficient future liver remnant (FLR) is required to select patients for liver preparation and limit the risk of post-hepatectomy liver failure (PHLF). The objective of this study was to investigate the correlations and discrepancies between the most-commonly used FLR volume metrics and Tc-99m-mebrofenin hepatobiliary scintigraphy (HBS). Methods: In 101 non-cirrhotic patients who underwent HBS before major hepatectomy, we retrospectively analyzed the correlations and discrepancies between FLR function and FLR volume metrics: actual percentage (FLRV%), standardized to body surface area (FLRV%(BSA)) and weight (FLRV%(weight)), and FLR to body weight ratio (FLRV-BWR). Results: Among 67 patients with FLR function 22.69%/min/m(2), PHLF was observed in none and 13 patients according to respectively 50-50 and ISGLS criteria. FLRV%, FLRV%(BSA), FLRV%(weight) and FLRV-BWR significantly correlated with FLR function (P<0.001), with Spearman's correlation coefficients of 0.680, 0.704, 0.698, and 0.711, respectively. No difference was observed between the areas under the curve of FLRV%, FLRV%(BSA), FLRV%(weight) and FLR-BWR (all P=ns). Overall, the percentages of patients misclassified by FLRV%, FLRV%(BSA), FLRV%(weight) (thresholds: 30%) and FLR-BWR (threshold: 0.5) versus FLR function (threshold: 2.69%/min/m(2)) were 23.8% (95% CI: 15.9-33.3%), 18.8% (95% CI: 11.7-27.8%), 17.8% (95% CI: 11-26.7%), and 31.7% (95% CI: 22.8-41.7%), respectively. FLR volume metrics wrongly classified 1-13.9% of patients with sufficient FLR function (i.e., 22.69%/min/m(2)), and 9.9-30.7% of patients with insufficient FLR function. FLRV-BWR was the most and the least reliable measure to identify patients with sufficient and insufficient FLR function, respectively. Conclusions: Despite significant correlations, the discrepancy rates between FLR volume and function metrics speaks in favor of implementing Tc-99m-mebrofenin HBS in the work-up before liver preparation.