Usefulness of the tactile sensor for estimating the degree of liver fibrosis and the DNA synthesis activity of remnant liver cells after partial hepatectomy.

BACKGROUND/PURPOSE Most patients with hepatocellular carcinoma in Japan also have liver cirrhosis. Therefore, reliable information about liver function is essential before undertaking liver resection. Occasionally preoperative estimates and intraoperative findings are disparate. This study used rats with liver fibrosis and a new tactile sensor to determine whether quantification of liver hardness intraoperatively can be used to validate the preoperative assessment of liver function prior to hepatectomy. METHODS Liver fibrosis was induced by administration of thioacetamide to rats. Laparotomy was performed. In some rats, blood samples were taken for examination, and liver stiffness and tactile values were measured by a new tactile sensor. A biopsy specimen from each removed liver was taken, and the hepatic fibrosis index was measured by computed color image analysis after Azan blue staining. The other rats underwent partial hepatectomy, and the bromodeoxyuridine labeling index was calculated in them. Correlations between stiffness, tactile values, and other data were calculated. RESULTS A strong correlation existed between stiffness and both the hepatic fibrosis index and the bromodeoxyuridine labeling index, and between tactile values and both the hepatic fibrosis index and the bromodeoxyuridine labeling index. CONCLUSIONS Liver hardness proved to be a function of hepatic fibrosis. The tactile sensor proved to be an easy and reliable way to evaluate the hepatic fibrosis index. Quantification of liver hardness by tactile sensor predicted liver regenerative activity.