Noninvasive estimate of bile flux through the gallbladder in humans

Objective: The aim of this study was to assess whether a single noninvasive technique, ultrasonography, is able in vivo: 1) to evaluate the time-related patterns of gallbladder bile storage and emptying, and 2) to quantitate the amount of bile flux through the gallbladder (GB). Methods: Healthy volunteers were submitted to the simultaneous assessment of gallbladder volume variations by frequent serial ultrasonographic (US) measurements and of hepatic bile flow through the GB by quantitative cholescintigraphy (QC) during continuous i.v. infusion of 99 mTc-HIDA. An ad hoc mathematical analysis of US GB volume measurements was used to estimate the amount of bile flux through the GB. The QC-derived measurements of the flux of hepatic bile through the GB was used to substantiate the US-derived estimates. Results: The curves expressing the time-related GB handling of hepatic bile obtained independently from US and QC measurements were statistically equivalent, and both techniques showed that the patterns and the amount of hepatic bile handled by the gallbladder after meal ingestion is remarkably different during three successive phases. After meals, hepatic bile was mainly 1) stored in the GB in the first phase; 2) emptied from the GB in a second phase; and 3) stored in the GB in the third phase. The ultrasonographic analysis estimated that 1) 23.8 ± 12.5 ml (0.44 ± 0.11 ml/min), 5.1 ± 3.9 ml (0.15 ± 0.10 ml/min), and 33.2 ± 10.5 ml (0.53 ± 0.16 ml/min) of hepatic bile entered into the GB during the three successive postprandial phases, and 2) the entire amount of bile flowing bidirectionally through the cystic duct, during the observation period (132.6 ± 23.3 ml) was about five-fold greater than that estimated by the usually employed variables. Conclusion: The proposed mathematical analysis of frequent ultrasonographic measurements of the GB volumes enables one to estimate noninvasively the flux of bile through the gallbladder in humans.