Value of gadoxetic acid-enhanced MR imaging for preoperative prediction of future liver regeneration after hemihepatectomy

Purpose Liver resection is currently considered the most effective treatment for patients with liver cancer. To the best of our knowledge, no study has investigated the association between gadoxetic acid-enhanced magnetic resonance imaging (MRI) findings and liver regeneration in patients who underwent hemihepatectomy. We aimed to clarify the relationship between the signal intensity (SI) of the liver parenchyma on gadoxetic acid-enhanced MRI and the degree of liver regeneration in patients who underwent hemihepatectomy. Materials and methods Forty-one patients who underwent gadoxetic acid-enhanced MRI before hemihepatectomy were enrolled. We calculated the liver-to-erector spinae muscle SI ratio (LMR) in the hepatobiliary phase and the precontrast images. Delta LMR was calculated using the following equation: Delta LMR = (LMR in the hepatobiliary phase-LMR in the precontrast image)/LMR in the precontrast image. The preoperative and postoperative remnant liver volumes (LVs) were calculated using CT volumetry. We calculated the resection rate (RR) and liver regeneration index (LRI) using the following formulas: RR = Resected LV/Total LV x 100 and LRI = (postoperative remnant LV-preoperative remnant LV)/preoperative remnant LV x 100. The relationships among LRI, imaging, and clinicopathological factors were analyzed. Results Univariate analysis showed RR and Delta LMR showed a positive correlation with LRI (rho = 0.4133, p = 0.0072 and rho = 0.7773, p < 0.001, respectively). Spleen volume showed a negative correlation with LRI (rho = -0.3138, p = 0.0486). Stepwise multiple regression analysis showed Delta LMR and RR were independently correlated with LRI (beta coefficient = 44.8771, p = 0.0198 and beta coefficient = 1.9653, p < 0.001, respectively). Conclusion Delta LMR may serve as a preoperative predictor of liver regeneration in patients undergoing hemihepatectomy.