Resection plane-dependent error in computed tomography volumetry of the right hepatic lobe in living liver donors

BACKGROUND/AIMS: Computed tomography (CT) hepatic volumetry is currently accepted as the most reliable method for preoperative estimation of graft weight in living donor liver transplantation (LDLT). However, several factors can cause inaccuracies in CT volumetry compared to real graft weight. The purpose of this study was to determine the frequency and degree of resection plane-dependent error in CT volumetry of the right hepatic lobe in LDLT. METHODS: Forty-six living liver donors underwent CT before donor surgery and on postoperative day 7. Prospective CT volumetry (V(P)) was measured via the assumptive hepatectomy plane. Retrospective liver volume (V(R)) was measured using the actual plane by comparing preoperative and postoperative CT. Compared with intraoperatively measured weight (W), errors in percentage (%) V(P) and V(R) were evaluated. Plane-dependent error in V(P) was defined as the absolute difference between V(P) and V(R). % plane-dependent error was defined as follows: |V(P)–V(R)|/W∙100. RESULTS: Mean V(P), V(R), and W were 761.9 mL, 755.0 mL, and 696.9 g. Mean and % errors in V(P) were 73.3 mL and 10.7%. Mean error and % error in V(R) were 64.4 mL and 9.3%. Mean plane-dependent error in V(P) was 32.4 mL. Mean % plane-dependent error was 4.7%. Plane-dependent error in V(P) exceeded 10% of W in approximately 10% of the subjects in our study. CONCLUSIONS: There was approximately 5% plane-dependent error in liver V(P) on CT volumetry. Plane-dependent error in V(P) exceeded 10% of W in approximately 10% of LDLT donors in our study. This error should be considered, especially when CT volumetry is performed by a less experienced operator who is not well acquainted with the donor hepatectomy plane.