The most appropriate formula for accurate calculation of standard liver volume for Thai population

Background: Living donor liver transplantation has been used for the treatment of end-stage liver disease due to the decline in organ donations. Living donor graft volume (GV) to recipient standard liver volume (SLV) ratio should be estimated before surgery to assess the degree of graft size disparity. In order to avoid post-operative liver failure, it is important to calculate SLV as a reference point for the minimal volume necessary for the recipient.

Objective: We determined which formula is the most appropriate and accurate for calculating SLV in the Thai population.

Materials and methods: One hundred twenty patients with multi-detector computed tomography (MDCT) of the upper or whole abdomen for conditions unrelated to hepatobiliary system with normal liver images between August 1, 2009 and March 31, 2010 were enrolled into the study. TLV measurements obtained from MDCT were compared to the SLV calculation based on the previously reported formulae.

Results: The formula derived from the Thai population by Hatthapornsawan S et al. was based on the body weight and its SLV estimation was the closest to TLV (ICC = 0.703). However, this formula underestimated SLV on average by 69.8 cc. The formula derived from the Japanese population by Urata et al. underestimated SLV by 97.7 cc with an ICC of 0.44. The body weight was found to correlate most closely with TLV (R² = 0.972, P<0.001). The new linear regression formula used to estimate SLV was modifies to SLV = 20.67 × body weight.

Conclusion: From the six previously reported formulae for the calculation of SLV, values obtained from the formula by Hatthapornsawan S et al. was the closest in estimating the liver volume in the Thai population but also slightly underestimated SLV. We have modified the formula. We recommend that Thai physicians use this new formula to calculate SLV because it is more accurate than the previously reported formula.