Figure 1-11. Particles of barium repelling one another in Barosperse.
b. Alternate Alimentary Tract Radiopaques. In figure 1-12, barium sulfate
was ingested during an upper G.I. The patient did not drink adequate liquids to flush
barium from his system, resulting in fecal impaction. The water is absorbed, leaving a
residue of barium sulfate particles. These particles would irritate the tissue they come
in contact with. This could result in inflammations, adhesions, or other undesirable
complications. Contrast media used when gastrointestinal perforations are suspected
should be soluble to avoid leaving an irritating residue. To achieve this end,
pharmaceutical companies adjust the activity of water-soluble injectable media to nearly
neutral. This renders them suitable for oral use. Two examples are Oral Hypaque and
Gastrografin. These soluble media leave no particles as residue. Therefore, they are
used as alternates in the alimentary canal when perforations are suspected.
c. Cholecystopaques. The biliary tract is examined with a group of contrast
media called cholecystopaques. These contrast media are chemically compounded to
be selectively excreted along with bile, by the liver. They may be oral or injectable.
(1) Oral cholecystopaques. One example of the oral type of
cholecystopaques is Telepaque. Available in tablet form, it is packaged in foil, six
tablets to the package. Instructions for their use are found on the package. The tablets
are dissolved in the stomach and absorbed by the mucosa of the small intestine,
specifically the duodenum and proximal jejunum. The portal system of veins carries the
dissolved media from there to the liver. The liver then excretes the media along with
bile. Telepaque and other oral cholecystopaques are employed in oral
(2) Injectable cholecystopaques. The other type of cholecystopaque is
injectable; therefore, it is called an intravenous cholecystopaque. One example is
Cholografin. This water-soluble medium is compounded specifically to be excreted by
the liver. Intravenous cholecystopaques are used for intravenous cholangiography.
Intravenous cholangiography is employed to visualize the biliary tract when the oral
method has failed in cases of poor intestinal absorption or after gallbladder surgery.