New horizons in transplantationLiver transplantationEstimation of Right-Lobe Graft Weight From Computed Tomographic Volumetry for Living Donor Liver Transplantation

•The present study developed right-lobe GW estimation formulas, based on graft volume without veins (GVw/o_veins) as well as graft volume with veins (GVw_veins): GW = 29.1 + 0.943 × GVw/o_veins (adjusted R2 = 0.94) and GW = 74.7 + 0.773 × GVw_veins (adjusted R2 = 0.87).•The GVw/o_veins-based formula developed in the present study was the most preferred (absolute error = 21.5 ± 16.5 g and percentage of absolute error = 3.0 ± 2.3%) compared with existing formulas.•Accurate CT volumetry and alignment between planned and actual surgical cutting lines are crucial in the establishment of a better GW estimation formula.

BackgroundThe objective of the study was to establish a right-lobe graft weight (GW) estimation formula for living donor liver transplantation (LDLT) from right-lobe graft volume without veins (GVw/o_veins), including portal vein and hepatic vein measured by computed tomographic (CT) volumetry, and to compare its estimation accuracy with those of existing formulas. Right-lobe GW estimation formulas established with the use of graft volume with veins (GVw_veins) sacrifice accuracy because GW measured intra-operatively excludes the weight of blood in the veins. Right-lobe GW estimation formulas have been established with the use of right-lobe GVw/o_veins, but a more accurate formula must be developed.MethodsThe present study developed right-lobe GW estimation formulas based on GVw/o_veins as well as GVw_veins, using 40 cases of Korean donors: GW = 29.1 + 0.943 × GVw/o_veins (adjusted R2 = 0.94) and GW = 74.7 + 0.773 × GVw_veins (adjusted R2 = 0.87). The proposed GW estimation formulas were compared with existing GVw_veins- and GVw/o_veins-based models, using 43 cases additionally obtained from two medical centers for cross-validation.ResultsThe GVw/o_veins-based formula developed in the present study was most preferred (absolute error = 21.5 ± 16.5 g and percentage of absolute error = 3.0 ± 2.3%).ConclusionsThe GVw/o_veins-based formula is preferred to the GVw_veins-based formula in GW estimation. Accurate CT volumetry and alignment between planned and actual surgical cutting lines are crucial in the establishment of a better GW estimation formula.