Ultrasonographic Studies of Gallbladder Emptying in Patients with Gallbladder Stone: With Parallel Studies of Gastric Emptying

The present study is designed to observe simultaneously both gastric and gallbladder emptying by ultrasound in order to determine whether impaired gallbladder emptying is consequent on delayed gastric emptying. Twelve gallstone patients and eleven normal controls were required to eat a standard mixed solid and liquid meal after an overnight fasting for 8 hr. The cross sectional area of the gastric antrum was calculated by elliptical method. The gallbladder volume was computed in cubic centimeters by ellipsoid method. As a result, the mean fasting and 120 min gallbladder volumes in gallstone patients are greater than that of normal controls (18.8±1.8cm^3 vs. 10.9±1.2cm^3 and 11.3±2.4cm^3 vs. 1.7±0.7cm^3, respectively) (P＜0.05) . The mean ejection fraction of gallbladder in gallstone patients (35%±14%) is less than that in normal controls (85%±6%) (P＜0.05). On the other hand, the mean maximal and 120 min antral areas and the gastric emptying fractions are similar in gallstone patients (15.3±1.8cm^2, 8.8±1.6cm^2, 70%±7%) and normal controls (18.2±1.9cm^2, 9.0±1.0cm^2, 73%±6%) (P＞0.05). When the time-gallbladder volume curves are compared between patients and controls, statistically significant differences are found (P＜0.05). However, the gastric emptying curves are similar in patients and controls (P＞0.05). In our study, the gallbladder of gallstone patients exhibit: 1) increased fasting volume, 2) decreased fractional emptying, and 3) increased postprandial residual volume. In addition, when we test the gastric and gallbladder emptying simultaneously, we find that the gastric emptying of control subjects exerts a stronger influence on the gallbladder emptying than that of gallstone patients. Therefore, delayed gallbladder emptying of gallstone patients is not likely to be due to delayed gastric emptying. As a result, other factors such as impaired innervation, abnormal smooth muscle of gallbladder or increased resistance to gallbladder emptying may have played a certain role in impeding gallbladder emptying of gallstone patients.