Simultaneous assessment of gallbladder emptying in the dog by real-time ultrasonography and strain gauge.

Patterns of meal- and cerulein-induced gallbladder emptying (GBE) were compared in four dogs equipped with a force transducer implanted onto the body of the gallbladder, and in four unoperated animals. GBE was examined by real-time ultrasonography in conscious dogs. In two dogs the ultrasonographic measurement of GBE was performed simultaneously with the registration of the strain exerted on the force transducer fixed on the gallbladder body. Implantation of the force transducer onto the gallbladder impaired neither postprandial nor cerulein-induced GBE. The contractile response of the gallbladder exhibited a non-linear relationship to the gallbladder volume. The reduction of gallbladder volume to 50% of its basal value was accompanied by an increase in strain amounting to about 16% of the maximum response, whereas a pronounced augmentation of the strain was observed with gallbladder volume ranging between 30% and 10% of the basal value. On the other hand, the contractile response of the gallbladder registered by means of a force transducer was linearly related to the angle alpha contained between two radii passing from the gallbladder center towards the edges of the strain gauge: y = 0.852 alpha-30.97 (r = 0.959, P < 0.001) in the case of i.v. cerulein infusion at stepwisely increasing doses (0.7-2.2-7.4-22.2-66.5 pmol.kg-1 h-1), and y = 0.640 alpha-17.40 (r = 0.869, P < 0.001) for a 1-h constant-rate 22.2 pmol.kg-1 h-1 cerulein infusion.