Measurement of portal systemic shunting by oral and per-rectal administration of [123I]iodoamphetamine, and clinical use of the results.

Abstract

OBJECTIVE. We used a method by which the portal shunt index via the superior mesenteric vein (SI-S) and that via the inferior mesenteric vein (SI-I) could be evaluated simultaneously. The clinical usefulness of the method was studied. Scintigraphy was done 3 h after subjects took an enteric-coated capsule containing [123I]iodoamphetamine. At that time, the radionuclide was injected into the rectum. Counts for the lungs and the liver were used to calculate the two shunt indices. The mean SI-S and SI-I tended to be higher for disorders that were more severe, increasing in the order of chronic persistent hepatitis, chronic aggressive hepatitis, and cirrhosis. In cirrhotic patients, the SI-I was higher than the SI-S (p < 0.001). The SI-S and SI-I were both higher in cirrhotic patients with esophageal varices than in such patients without varices (p < 0.05 and < 0.001). The SI-S and SI-I were higher in cirrhotic patients with ascites than in such patients without ascites (p < 0.001 and < 0.01). Correlation between either of these indices and classical indicators of functional reserve was high. The correlation of SI-S with the Child-Turcotte classification and total bilirubin level was higher than the correlation of the SI-I and these indicators of functional reserve. This method permits assessment of the portal hemodynamics in a relatively noninvasive way, and is clinically meaningful.