Clinical Studies on Hepatic Excretion Mechanism of Indocyanine Green in Liver Diseases

Abstract

The author has fortunately experienced a healthy female volunteer for normal control of indocyanine green (ICG) test who have showed very low disappearance rate (K), which showed 0.031, whereas the other liver function tests were within normal limits including BSP test. It is the purpose of present study to clarify the disturbance of ICG uptake-excretion mechanism in this volunteer.
Firstly, ICG (0.5mg/kg), ¹⁹⁸Au colloid (5-10 μCi) and ¹³¹I-rose bengal (5-10μCi) were injected simultainously for the determinations of disappearance rate (K, K_AU and K_RB). And then, by the application of the continuous infusion method, ICG was perfused intravenously at the rate of three different infusions, and the estimated maximum rate of biliary excretion (Tm) and the estimated relative hepatic storage capacity (S) were examined. The total number of examinations was 63 in 57 cases with liver diseases.
The distribution of K values of these cases were similar to the other reports. Normal values (M & plusmn;SD) for Tm and S were 0.89 & plusmn;0.19 mg/min and 328.5 & plusmn;143.9mg/mg%, respectively. Tm and S were decreased in accordance with the degree of liver damage, and only cases with liver cirrhosis were markedly low in the values of Tm and S. No correlation between Tm and S was observed. The correlation coefficient between K and S (r=+0.79, p<0.005) was higher than that between K and Tm (r=+0.51, p<0.005). K was significantly correlated with K_AU at r=+0.49 and K_RB at r=+0.80. The values of K_AU were within normal range both in Rotor's syndrome and the ICG abnormality case above described, however the discrepancy of K_RB (respectively 0.009 and 0.053) such as BSP retention rate and serum bilirubin concentration was observed in these two cases.
On the basis of these results, the author suggested that a healthy female with abnormal ICG test had the disturbance of the uptake mechanism and storage capacity of liver cells for ICG.