Contrast Studies Flashcards
What are the three most commonly performed contrast studies?
GI, urogenital, spinal cord
What are the factors that determine the type of contrast agent used?
test being performed, level of comfort of the clinician, availability
What are the four types of contrast agents commonly used?
- Soluble ionic radiopaque mediums
- Soluble nonionic radiopaque mediums
- Insoluble inert radiopaque mediums
- Radiolucent gases
What are examples of soluble ionic radiopaque mediums?
Iothalamate, diatrizoate
What are examples of soluble nonionic radiopaque mediums?
Iohexol, iopamidol
What is an example of insoluble inert radiopaque mediums?
barium sulfate
What are examples of radiolucent gases?
air, nitrous oxide, carbon dioxide
Soluble ionic mediums are _________
negatively charged benzoic acid derivatives
What are soluble ionic mediums used for?
oral administration for GI studies, IV for excretory urography, intraarticular studies, draining wound studies, fistulography
What type of patients shouldn’t receive soluble ionic mediums?
dehydrated patients
patients that are sensitive to iodine
***contrast is hyperosmolar salts (causes an increase in intravascular fluid volume when given IV)
What is the side effect of giving soluble ionic mediums orally?
diarrhea
direct contact w/ neural tissue can lead to muscle spasms, seizures, cerebral edema, hypotension, coma, death
Soluble ionic mediums are _____ contrast agents
positive
What studies can be performed using nonionic radiopaque agents?
spinal cord or respiratory tract, myelography
What are examples of soluble nonionic mediums?
iohexol, iopamidol
What is a benefit associated with nonionic mediums?
lower incidence of adverse effects & a lower osmolality
Nonionic agents are ______ contrast agent
Positive
What does BIPS stand for?
Barium impregnated polyethylene spheres
Barium is a more ________ solution than the surrounding tissue
dense
Due to barium suspension being more dense than the surrounding tissue, what does it result to?
Greater absorption of xrays & produces a whiter image on the finished radiograph
What are the benefits of barium suspension?
increase radiographic opacity –> allows the clinician to easily evaluate the surrounding structures
Due to barium suspension not being absorbed by the surrounding tissue, what does it do?
It effectively coats and soothes the GI tract compared to ionic mediums & it provides increased visualization of the lumen surfaces
What are two systems used to measure barium suspension?
- weight to volume (w/v)
- weight to weight (w/w)
Insoluble agents are ______ contrast agents
positive
What forms does barium come in?
paste, liquid, powder
What study is the barium paste used for?
esophagography studies
Why is barium paste used for esophagography studies?
easier to administer, less likely to cause aspiration, adheres to the mucosa better than liquid barium
What type of patients should barium not be used for?
constipation, any risk of upper or lower perforation of GI tract
How should barium be administered if not evaluating the esophagus?
via orogastric tube to decrease risk of aspiration
What is the drawback of powder barium?
over dilution w/ water –> which results in a solution too thin and doesnt coat the system well enough to provide diagnostic info
What forms of barium outline the upper and lower GI system better ?
liquid and paste (better than powder)
When are BIPS used?
used to determine if a motility issue is present
What are BIPS related to in terms of structure?
Due to chemical structure, they are placed in the same group as barium sulfate agents;
Due to inert structure, they maintain the same weight as ingested food
What form does BIPS come in?
capsule
True or False: Each animal received the same volume of BIPS to evaluate for motility
True
Can BIPS be given with our without food?
both
The larger BIPS capsule contains ______ spheres; The smaller BIPS capsule contains _____ spheres
10 (5 mm diameter); 30 (1.5 mm diameter)
What is the purpose of small BIPS?
to be similar to food and to assist in eval of motility
What is the purpose of large BIPS?
determine if there is a potential obstruction in the GI tract
What does BIPS offer an evaluation of besides motility?
gastric emptying times as liquid is released from the stomach in a shorter time compared to solids
True of False: Liquid barium can give a false negative to motility issues due to its consistency
True
Radiolucent gases are ____ contrast agents
Negative
What affect does radiolucent gases have on radiographs?
the gases absorb fewer x-rays than the surrounding soft tissue & result in a more radiolucent effect
What do negative contrast agents normally combine with?
positive contrast agents in a study referred to as a double contrast study
What is a double contrast study?
a study that uses both a positive and negative contrast agent to evaluate an organ system
Negative contrast agents provide _____ mucosal detail than the positive contrast agents used
less
When should care be taken when using negative contrast agents?
prevent over expansion of hollow organs (results in potential rupture)
What are the agents of choice when performing negative contrast studies? Why?
CO2 and Nitrous Oxide
Because use of room air can produce an air embolism that can result in cardiac arrest
What is an esophagography?
A contrast study of the esophagus to assess the status of the esophagus, potential motility issues, and surrounding tissue
What is the best position for the patient when performing an esophagography?
Standing (less risk of aspiration)
What else should be performed when doing a esophagography?
Fluoroscopy
Why would an esophagography be performed?
Abnormal swallowing, foreign body obstruction, dysphagia, megaesophagus, regurgitation of undigested food, and head/neck trauma
What media is used for esophagography?
barium sulfate liquid or paste, commonly mixed w/ canned food
Oral aqueous iodine is used if perforation of the esophagus or GI tract is of concern
