Estimation of Right-Lobe Graft Weight From Computed Tomographic Volumetry for Living Donor Liver Transplantation

Background The 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 (GV_{w/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 (GV_{w_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 GV_{w/o_veins}, but a more accurate formula must be developed. Methods The present study developed right-lobe GW estimation formulas based on GV_{w/o_veins} as well as GV_{w_veins}, using 40 cases of Korean donors: GW = 29.1 + 0.943 × GV_{w/o_veins} (adjusted R² = 0.94) and GW = 74.7 + 0.773 × GV_{w_veins} (adjusted R² = 0.87). The proposed GW estimation formulas were compared with existing GV_{w_veins}- and GV_{w/o_veins}-based models, using 43 cases additionally obtained from two medical centers for cross-validation. Results The GV_{w/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%). Conclusions The GV_{w/o_veins}-based formula is preferred to the GV_{w_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.