ObjectiveTo improve the calculation method of the sum of residual hepatic lobe volume and total liver volume after partial hepatectomy in rats.MethodsOne hundred and thirty-five SD rats of different body sizes were divided into five groups by completely random design. The body length, tail length, chest circumference, body weight and length of hepatic triangle lobe of the rats were measured before surgery. Then, according to the classic Higgins and Anderson methods, different lobectomies of liver were performed for each group: middle lobe + left inner lobe, left outer lobe, bilateral papillary lobe, triangular lobe, and right lateral lobe were removed; the proportion of theoretical liver resection in each group was 38.1%, 30.1%, 7.9%, 7.8% and 15.3%, respectively. The actual liver resection volume and residual liver volume were measured after surgery. we finally analyzed statistical differences of liver volume calculated by different indirect methods. In addition, the correlation analysis and regression analysis were conducted between the preoperative measured rat body surface parameters and the measured whole liver volume, so as to explore a more simple and accurate volume measurement method.ResultsThe actual proportion of liver resection in each group was 35.0%, 29.2%, 7.1%, 4.9% and 12.0%, respectively. Compared with the residual liver lobe volume actually measured, that calculated by using the indirect method of substitution of the theoretical liver resection proportion was statistically different in all the other four groups except the left outer lobe group. However, there was no statistical difference between the residual liver lobe volume actually measured and that calculated by the actual liver resection proportion in the 5 groups. In addition, in the preoperative measurement of 5 kinds of basic parameters of rats, the body length has the best correlation with whole liver volume, and the regression equation is \begin{document}$\hat Y = - 27.667 + 0.899X$\end{document}.ConclusionsThe liver volume calculated by indirect method using the actual liver resection proportion, compared with the theoretical liver resection proportion, is more accurate. Compared with the body weight, the body length has the better correlation with whole liver volume.