Evaluation of the Effect of Age on Functioning Hepatocyte Mass and Liver Blood Flow Using Liver Scintigraphy in Preoperative Estimations for Surgical Patients: Comparison with CT Volumetry

Abstract

Background. The effect of age on functioning hepatocyte mass and liver blood flow was examined using 99mTc-galactosyl-human serum albumin (GSA) liver scintigraphy in patients with liver tumors awaiting surgery. Materials and methods. Seventy-two patients with liver tumors, but normal liver parenchyma, were included in this study; patients with compromised hepatic blood flow as a result of vascular invasion or thrombus were excluded. The liver volume, calculated liver volume, and liver blood flow index ( K value) were preoperatively determined by liver scintigraphy using GSA. These three parameters and liver volume measured by computed tomography volumetry (CT-LV) and the standard liver volume (ST-LV), calculated from the patient's body surface area, were examined for correlations with the patient's age. The K value was compared with the indocyanine green dye retention rate, and both sets of results were examined for correlation with the patient's age. Results. Both the CT-LV and the ST-LV decreased with age, resulting in an unchanged CT-LV/ST-LV ratio with aging. The liver volume and calculated liver volume measured by scintigraphy both decreased with age, even when body size was taken into account. Therefore, in elderly patients, the liver was not morphologically smaller, but the hepatocyte mass in the liver decreased. Furthermore, liver blood flow per unit of functional liver volume determined from the blood flow index did not change with age. Conclusions. These results, suggesting a discrepancy between liver volume estimated by CT and actual functioning hepatocyte volume in the elderly, may have a critical impact on preoperative liver functional reserve evaluation prior to hepatic resection in elderly patients.