Contrast Studies Flashcards
Indications for contrast studies (4)
- Used to supplement or confirm information garnered from routine survey radiographs.
- Lack of contrast in soft tissue makes some diagnosis hard.
- Contrast medium-substance that is either radiolucent or radiopaque and can be administered to an animal to increase radiographic contrast within an organ or system.
- Should not be used to replace survey radiography.
What are the two general categories of contrast media?
- Positive contrast agents
- Negative contrast agents
Positive vs Negative contrast agents
Positive
- Iodinated preparations
- Barium sulfate preparations
Negative
- Gases (air)
Positive contrast agent’s substances containing what?
Elements of high atomic number that are more radiopaque to x-rays then tissue & bone and have white appearance on a radiograph.
Negative contrast agents are…
Gases that are more radiolucent to x-rays than soft tissues and have a black appearance on a radiograph.
- Oxygen, CO2, room air
Iodine preparations (3)
- Most are opaque to x-rays, pharmacologically inert, low in viscosity for rapid intravenous injection, low in toxicity, rapidly excreted by the kidneys, and chemically stable so that no iodine is released in the body.
- Tri-iodinated compounds- a common component of iodinated positive-contrast media that contains three atoms of iodine per molecule.
- Well tolerated by body and provide
excellent contrast. - Can be injected into a vascular system for immediate visualization or infused into the bladder.
Water soluble contrast media
1. IV injection (3)
2. Oral use (1)
3. CM for intra thecal injection (1)
- IV
- Urographin (most popular)
- Isovist
- Telebrex - PO
- Gastrographin - CM
- Iohexol (omnipaque)
Barium sulfate is completely ____, not diluted or ___ through the intestines. Available in liquid, ___, & ___ that can be reconstituted with water.
If a perforation is present, barium may ___ and be in the body ___.
- Insoluble
- Absorbed
- Paste, & Powder
- Pass
- Indefinitely; forever
Carbon dioxide has an advantage over room air because is it better ___ into the body when administered into a hollow organ. Room air can cause air ___.
These are ___, relatively ___, and ___ to administer.
- Absorbed
- Emboli
- Inexpensive
- Safe
- Easy
Double contrast, what is it?
A radiographic contrast technique that uses a combination of both positive & negative-contrast media simultaneously.
Three routes GI contrast study substance can be administered
- PO
- NG tube
- Enema
Patient prep (6)
- Food withheld for 12-24hrs
- If necessary, enema - Sedation
- Avoid drugs with anticholinergic effects (ex: atropine) - Scout image to start!!
- Give the proper amount of contrast agent!
- Underdosing causes artifact filling defects - Avoid getting contrast on fur
- Rads are carefully timed & labelled to show time from start of study.
Esophagram
1. Indications (4)
2. Forms it comes in (3)
3. Image timing
- Indications
- Eval esophageal function & morphology
- Hx of regurg undigested food
- Acute gagging
- Dysphagia - Forms
- Barium
- Barium paste
- Barium meal (w/food) - Immediately after barium is given
Esophagram precautions (2)
- Make sure pt is not able to aspirate barium.
- If concern about perforation or rupture, iodinated agent should be used instead.
Upper GI Study
1. Evaluating what
2. Indications (5)
3. Image timing
- Evaluating the stomach & small intestines
- Indications
- Recurrent & unresponsive vomiting
- Abnormal bowel movements
- Suspected foreign body or obstruction
- Chronic weight loss
- Persistent abdominal pain - Rads taken during passage of agent
Upper GI (UGI) study precautions (1)
If perforation or rupture is suspected, barium should not be used, but water soluble-iodine agent.
Volume of barium to be administered should be: __mL/kg
High dose is recommended for ___ & small ___ while low dose is recommended for large ___.
a. 6-12mL/kg
b. Cats & small dogs
c. Large dogs
Frequency of images needed for GI contrast study (7)
What are barium impregnated poly spheres (BIPS)? (4)
- Created to study gastrointestinal motility.
- Used to identify areas of intestinal stricture of obstruction.
- The impregnated spheres are packaged in gelatin capsules, each capsule containing a number of spheres.
- Usually there will be a mixture of small and large spheres.
- Helpful when determining whether there is a partial or complete intestinal obstruction.
Lower GI (LGI) study
1. Evaluates what? (3)
2. Indications (6)
3. Administration method/route
- Evaluates the rectum, colon, & cecum
- Indications
- Full distension of the large intestine is necessary.
- Intussusception
- Rectal mass
- Abdominal mass
- Stricture
- Colonic obstruction - Via enema with any three types of contrast mediums
Lower GI (LGI) study precautions (2)
- If perforation or rupture is suspected, barium should not be used, but water soluble-iodine agent.
- Patient should have all feces and colonic contents removed prior to administration.
Urinary contrast study
1. Evaluates what? (4)
2. Indications (7)
- Evaluates kidneys, ureters, bladder, & urethra.
- Indications
- Hematuria
- Proteinuria
- Crystalluria
- Polyuria
- Isothenuria
- Dysuria
- Urinary incontinence
T/F: Urinary contrast studies are fairly expensive and have a low diagnostic rate
False! These are relatively inexpensive and have high diagnostic rates
