Contrast Studies Flashcards
What is contrast media used for?
To visualise soft tissue structures.
Why are some soft tissue structures harder to identify on plain films?
Lack of surrounding contrast.
What does contrast media provide ?
Further information about the position, size, shape, internal surface and function of the tissue.
What are the two major types of contrast media?
Positive and negative
Describe negative contrast media
Gases with low atomic numbers and low density, appear black on the radiograph
What word describes appearing black on a radiograph?
Radiolucent
Give examples of negative contrast media
Air, oxygen, nitrous oxide, carbon dioxide.
What structures can you use negative contrast media with?
Bladder, gut, joints, peritoneum.
List the advantages of negative contrast media
Cheap, quick, convenient
Safe
Reabsorbed fairly quickly
List the disadvantages of negative contrast media
Used alone they give poor mucosal detail.
Risk of air embolism if tissue is inflamed
Describe positive contrast media
Radiodense/radiopaque due to their high atomic number and high density
List types of positive contrast media
Barium sulphate preparations, ionic water soluble iodine containing compounds, non-ionic water soluble iodine containing compounds
What forms do barium sulphate preparations come in?
Powder, paste, or liquid.
Describe barium sulphate preparations
Inert substance, not absorbed by tissues.
Low toxicity, no osmotic effect.
What are barium sulphate preparations mainly used for?
Studies of the alimentary tract.
