The main functions of the gall-bladder are to concentrate and store bile that is produced in the liver and to empty it into the duodenum after appropriate stimuli.
Oral Cholecystogram: The organ is investigated by performing oral cholecystography. This procedure depends on the fact that certain iodine-containing compounds, when absorbed in the gastrointestinal tract, are excreted by liver and concentrated in the gall-bladder, thus rendering it opaque.
A contrast mixture is taken by mouth which appears in the gall-bladder. An X-ray taken of the gall-bladder reveals its outline as well as any abnormality, including stones in it or any narrowing or obstruction due to any cause. It usually takes about two hours to complete the test.
Intravenous Cholangiography: It is used to demonstrate the bile ducts. The technique depends on the fact that an intravenously administered, iodine-containing compound is excreted by the liver in the bile in such a concentration that it is radio-opaque, i.e. opaque to X-ray and, therefore, does not depend on the concentrating power of the gall-bladder, as in cholecystography.
ERCP (Endoscopic Retrograde Cholangiopancreatography: This examination is done to visualize the ducts of the gall-bladder and the pancreas.
The flexible gastroscope is entered into the duodenum and there, the ducts of the gall-bladder and the pancreatic openings are recognised. A fine catheter (plastic tube) is passed down the gastroscope and into one of the ducts. When the catheter is in the duct, which is visualized on television screen, a small quantity of the radio-opaque dye is injected into the duct to be investigated, and its outline seen and X-rayed to assess whether there is any obstruction in it or not.
This test requires a very skilled gastroscopist. The patient is not put to much discomfort and the test is over in about an hour.