Single photon emission computed tomography to determine effective hepatic blood flow and intrahepatic shunting

The noninvasive determination of effective hepatic blood flow, intrahepatic shunted blood flow, intrahepatic shunt index, and total hepatic blood flow was investigated by using the sequential single photon emission computed tomography. This method was performed for a period of 10 minutes following an intravenous injection of 99mTc-(Sn)-N-pyridoxyl-5-methyltryptophan and a venous blood sampling. This study comprised 8 healthy volunteers, 16 patients with chronic hepatitis, and 33 patients with liver cirrhosis. The intrahepatic shunt index measured with this method coincided with the intrahepatic shunt index determined by catheterization, indicating the high reliability of this procedure. The effective hepatic blood flow in patients with liver cirrhosis was significantly lower than that in the healthy controls and the chronic hepatitis group. The intrahepatic shunted blood flow was significantly higher in patients with liver cirrhosis compared with the flow in healthy controls. The intrahepatic shunt index was also significantly higher in patients with liver cirrhosis compared with the index of healthy controls and those with chronic hepatitis. No substantial differences were noted in the total hepatic blood flow among the three groups. The effective hepatic blood flow, the intrahepatic shunted blood flow, and the intrahepatic shunt index, correlated with the serum albumin concentration, the serum cholinesterase level, and the plasma indocyanine green attenuation rate. From these results, it was concluded that the present procedure constitutes a reliable and effective method for the noninvasive determination of hepatic blood flows. Consequently, it will be of high clinical value for assessing the functional and the pathological alterations of the liver.