Right Lobe Estimated Blood-free Weight for Living Donor Liver Transplantation: Accuracy of Automated Blood-free CT Volumetry-Preliminary Results

To determine the relative accuracy of automated blood-free to blood-filled computed tomographic (CT) volumetry for estimation of right-lobe weight in living donor liver transplantation. This retrospective study was approved by the institutional review board; informed consent was waived. Between October 1, 2008, and April 30, 2009, 88 live liver donors (54 men, 34 women; mean age, 26.1 years +/- 6.9 [standard deviation]) who underwent CT and had their right lobes procured in the study institution were included. Automated measurement of blood-filled volume (V(BFill)) and blood-free volume (V(BFree)) of the right lobe was performed by using 16-row multidetector CT performed with 5-mm intervals. Actual hepatic weight was measured blood free during surgery. Percentage blood volume, %V(B), was calculated as follows: %V(B) = V(BFill) - V(BFree)/V(BFill) . 100. Pearson tests were performed to determine correlation coefficients between V(BFill)/1.22 or V(BFree) and weight. Percentage deviation and percentage absolute deviation of V(BFree) from weight were compared with those of V(BFill)/1.22 by using a paired t test or Wilcoxon rank sum test. Regression analysis was performed between V(BFree) and weight. Mean V(BFill), V(BFree), and weight were 789.0 mL +/- 126.4, 713.9 mL +/- 114.4, and 717.8 g +/- 110.4. Percentage blood volume varied from 6.5% to 19.8% (mean, 9.5%). Compared with weight, the correlation coefficient was slightly higher with V(BFree) (r = 0.9140) than with V(BFill)/1.22 (r = 0.8909). Mean percentage deviation and percentage absolute deviation were significantly smaller with V(BFree) (-0.4% +/- 6.3, 5.0% +/- 3.8; P < .001) than with V(BFill)/1.22 (-9.8% +/- 6.5, 10.2% +/- 7.3; P < .001). The equation relating V(BFree) and weight, W, was as follows: W = (0.8815 . V(BFree)) + 88.5117, with R(2) of 0.8355 (P < .001). At automated CT volumetry in live liver donors, the percentage blood volume varies. The V(BFree) is more accurate than is V(BFill)/1.22 in estimation of hepatic weight.