Variation of enterohepatic circulation observed with 75 SeHCAT images in the first three hours. Scintigraphic patterns and analysis of their association with the diagnosis of bile acid malabsorption.

Objetive: To evaluate the enterohepatic circulation of 75-Selenium turoselecolic acid ( ⁷⁵ Se-SeHCAT) during the first 3 h and its correlation with the abdominal retention at the 7th day (AR ₇ ), as contribution to the clinical study of biliar acid malabsorption (BAM).
Materials and Methods: 38 patients with chronic diarrhea were retrospectively studied. Acquisition protocol included static abdominal images at 1st, 2nd and 3rd hour and the 7th day after oral administration of the radiopharmaceutical. Images of 1-3 h determined 5 patterns of enterohepatic circulation that, due to their location, were characterized as: 1) gallbladder 2-3 h, 2) gallbladder 3 h, 3) gallbladder-abdomen 2-3 h, 4) abdomen, 5) upper left abdomen. The association of these patterns with the AR ₇ (Fisher, STATA) were investigated. Patients were classified as Non BAM (AR ₇  > 15%), mild-BAM (AR ₇ 15-10%), moderate-BAM (AR ₇ 10-5%) or severe-BAM (AR ₇  < 5%).
Results: 19 patients had an AR ₇ diagnostic of BAM (7 mild-BAM, 5 moderate-BAM, 7 severe-BAM). The pattern "gallbladder at 2-3 h" was statistically associated with Non BAM (p 0,008), while "gallbladder-abdomen at 2-3 h" was correlated with having BAM (p 0,029).
Conclusion: Variations detected at the abdominal level in images during the first 3 h were associated with changes in intestinal absorption and the incorporation of the radiopharmaceutical into the pool of bile acids, so visual interpretation of the images at 2nd and 3rd hour could be useful in the final assessment of the study.
(Copyright © 2021 Sociedad Española de Medicina Nuclear e Imagen Molecular. Published by Elsevier España, S.L.U. All rights reserved.)