Assessment of portosystemic shunt by summation of radioactivity during 201thallium chloride portal scintigraphy in patients with chronic liver disease.

Background/aims: Portal scintigraphy is a useful non-invasive method for the determination of portosystemic shunts in patients with liver cirrhosis. Several procedures have been reported for its execution in clinical practice but most of them failed to show sufficient sensitivity for the diagnosis of portosystemic shunt. In the present study, we evaluated whether summation of radioisotope counts obtained during intrarectal or intraduodenal administration of 201thalium chloride is useful for increasing the diagnostic yield of porto-systemic shunts in patients with chronic liver disease.
Methodology: Seven patients with chronic viral hepatitis and 8 with liver cirrhosis secondary to viral hepatitis were enrolled in this study. Following the conventional protocol, 201thalium chloride was administered per rectum and the 60-second-heart-to-liver uptake (conv-H/L-R) ratio was calculated after 20 min. Continuous measurement of the radioactivity signals during 20 min were also done and the summated heart-to-liver uptake (sum-H/L-R) ratio from the total radioactivity count were calculated. Measurement of the conventional heart-to-liver uptake (conv-H/L-D) ratio and the summated (sum-H/L-D) ratio were also done as described above after the intraduodenal administration of 201thalium chloride by endoscopy.
Results: All ratios (conv-H/L-R, conv-H/L-D, sum-H/D-R, sum-H/L-D) were significantly higher in patients with liver cirrhosis than in those with chronic hepatitis. Among all heart/liver ratios, only the sum-H/L-R ratio was significantly different between patients with and without esophageal varices. Serum hyaluronate level and other liver function tests were found to be significantly correlated with all heart-to-liver ratios, but they were more strongly correlated with the sum-H/D-R and sum-H/L-D ratios than with the conv-H/L-R and conv-H/L-D ratios.
Conclusions: The results of this study showed that the heart-to-liver ratio calculated by summation of radioactivity is better than the conventional method for the diagnosis of portosystemic shunt in patients with chronic liver disease.