Preoperative evaluation of future remnant liver function is critical for patients undergoing hepatic surgery. Overestimation of the remnant liver function can lead to life-threatening postoperative hepatic failure, and its underestimation can lead to a lost opportunity for potentially curative surgery. Conventionally, post-hepatectomy remnant liver function has been estimated preoperatively using computed tomography (CT) volumetry. CT can provide precise anatomical information, and the remnant liver volume, measured by CT volumetry, has been reported to be an effective predictor of hepatic dysfunction after hepatectomy. However, the indirect estimation of liver function by CT volumetry is reliable only when the function is assumed to be homogenous over the whole liver.