In normal subjects, thallium-201, administered per rectum, is taken up mainly by the liver (heart/liver ratio in normal subjects: 0.04 to 0.12). It has been claimed that an increased heart/liver ratio is suggestive of portal-caval shunting and portal hypertension. To evaluate the possibility of using thallium-201 as a test to diagnose cirrhosis, we administered this substance per rectum to 33 patients with biochemical evidence, but no clinical symptoms, of liver disease. Laparoscopy and liver biopsy revealed chronic active hepatitis without cirrhosis in 18 patients, and chronic active hepatitis with cirrhosis in the others. The results of conventional liver function tests were similar in both groups. A significant difference, however, was found between the means of fasting serum bile acid concentrations (9.8 ± 3.2 and 18.3 ± 4.2 μM per liter) in chronic active hepatitis without cirrhosis and cirrhotic patients, and between the means of the heart/liver ratios 20 min after thallium-201 administration (heart/liver: 0.09 ± 0.03 and 0.54 ± 0.13, respectively). Unlike the serum bile acid concentration which gave some overlapping values, the thallium-201 test clearly distinguished the chronic active hepatitis without cirrhosis group from the cirrhotics.
In the cirrhotic group, there was a significant correlation between the heart/liver ratio and signs of portal hypertension such as esophageal varices, increased diameter of the vena porta and hypersplenism.
The thallium-201 test is therefore useful in discriminating between chronic active hepatitis with and without cirrhosis in clinically asymptomatic subjects with biochemical evidence of moderate liver function impairment. A heart/liver uptake ratio much higher than normal (above 0.30) strongly suggests the development of hepatic cirrhosis.