Test 2: lecture 8 Flashcards
types of contrast studies
___ are a type of positive contrast
barium and iodine
___ are a type of negative contrast
room air
CO2
___ is a type of double contrast
barium and gas
iodine and gas
pneumocystogram
place urinary catheter
remove urine, place air
where can you use negative contrast?
put air in area to make wall thickness apparent and outline hollow organs
bladder: pneumocystogram
colon: pneumocolon
stomach: pneumogastrogram
advantages, disadvantages and risks of negative contrast
add air to area
Advantages:
¨ Always available, cheap
Disadvantages:
¨ Limited info
Risks:
¨ Over distention and rupture
¨ Air embolism (= obstruction of a blood vessel caused by the entrance of air into the bloodstream). (CO 2 better soluble à risk ↓↓)
positive contrast is used for
(add high atomic number substance→ radiopaque → white)
Outlining of internal surface of hollow organs, vessels
and ducts
Organ location and size
Wall thickness
Filling defects
Viscus rupture
intraluminal filling defect
positive contrast
calculus, blood clot, FB, gas bubble
intramural filling defect
positive contrast
arising from the wall (mass-neoplasia, abscess granuloma, polyp) even if occupies the entire lumen!
extraluminal filling defect
seen in positive contrast study
a lesion outside the images organ, compressing/displacing it
what kind of positive contrast can only be used in the GI tract
barium
What positive contrast can be used for transit and emptying times of the GI tract
barium
advantages of barium
positive contrast
Relatively cheap
¨ Relatively tasty
¨ Good mucosal coating (imaging, curative?)
¨ Non-toxic, No side effects (intraluminal)
¨ If aspirated- usually benign (from bronchi-expectorated. From alveoli- phagocytosed and transported to tracheobronchial ln)
disadvantages of barium
Can only be used in the GI tract (+ airways).
¨ Leakage into mediastinum or peritoneum →inflammation, fibrosis and granuloma formation. Surgical emergency. → DO NOT USE IF GI RUPTURE IS SUSPECTED!
¨ Should not be used pre- or post endoscopy ( pre- blocks vision, post- risk of leakage↑)
if GI perforation is suspected or pre endoscopy what positive contrast should be used
iodinated medium
esophagram
give barium or iodine to look at esophagus
when to use barium enema
tell the difference between small and large bowel loops
masses, strictures, ect
ionic iodinated contrast
Dissociate into anions and cations → hyperosmolar.
Side effects (mainly due to hyperosmolarity)
Cost ↓
non-ionic iodinated contrast
Do not dissociate into anions and cations → hypoosmolar.
Side effects much less severe and less common.
Cost ↑
in the GI tract what happens to ionic iodinated contrast
ionic → hyperosmolar, this means fluids will be drawn in → dilutes the contrast and decreases image quality
where can you not use ionic iodinated contrast media
intrathecal injection (myelogram) → spinal cord
where can you use iodinated contrast
you can use it almost anywhere
intravenous urogram
inject iodine into the veins, this will travel to the kidneys to be excreted
makes kidneys easier to see
for viscus rupture what kind of contrast is recommended
Positive Iodinated Contrast Medium
Positive: largest contrast with normal body opacities (negative- same as gas in lungs or GI).
Iodinated: can’t use barium in peritoneal cavity or mediastinum → inflammation.
Preferably non-ionic: ionic medium pulls more fluid (hyperosmolar).
when to use double contrast
gas and barium
gas and iodine
used most commonly in the bladder
what is the advantage of double contrast
can see very small detects because the gas provides a dark background
Examples of intra-luminal filling defects are…
Abscess, sludge
Blood clots, polyps
Granulomas, air
Bladder calculi, gas bubbles
Neoplasia, foreign body
Bladder calculi, gas bubbles
In a colonogram, when the colon does not fill up well with contrast medium due to an enlarged prostate, this is an example of an…
Intra-mural filling defect
Intra-luminal filling defect
Extra-ordinary filling defect
Not enough information provided to determine nature of filling defect
Extra-luminal filling defect
Extra-luminal filling defect
For which of the following studies barium should NOT be used?
Bronchogram
Colonogram
Retrograde vaginogram
Esophagram
Gastrogram
Retrograde vaginogram
A pyelogram is a sensitive study to rule out…
Vascular anomaly
Urethral obstruction
Urinary bladder calculi
Ureteral obstruction
Urinary bladder tear
Ureteral obstruction
An appropriate choice of contrast media for a double contrast cystogram would be…
Ionic and non-ionic iodine
Barium and iodine
Iodine and saline
Iodine and CO2
Barium and room air
Iodine and CO2
In a colonogram, when the colon does not fill up well with contrast medium due to an enlarged prostate, this is an example of an…
Not enough information provided to determine nature of filling defect
Extra-ordinary filling defect
Intra-luminal filling defect
Intra-mural filling defect
Extra-luminal filling defect
Extra-luminal filling defect
For which of the following studies barium should NOT be used?
Esophagram
Gastrogram
Bronchogram
Colonogram
Retrograde vaginogram
Retrograde vaginogram
Which of the following may be a reason to choose iodine over barium?
Minimizing side effects in a hypovolemic patient
Expecting endoscopy may be required after the contrast study
Financial concerns
Wanting to optimize mucosal coating
Suspecting urinary bladder ulcerations
Expecting endoscopy may be required after the contrast study
Using an ionic iodinated contrast medium may…
Be recommended for a patient with heart disease
Be the first choice for an esophagram in most patients
Be a safer choice for an unstable patient
Be used for a myelogram
Result in poorer image quality in the GI tract
Result in poorer image quality in the GI tract
A pyelogram is a sensitive study to rule out…
Ureteral obstruction
Urinary bladder tear
Urethral obstruction
Urinary bladder calculi
Vascular anomaly
Ureteral obstruction
A cat is vomiting and possibly ingested a small ball last night. You would recommend to perform a ___ using ___
upper GI contrast study
barium (could use iodinated agent if the ball is still in the stomach and endoscopy for removal is considered after the contrast study..)
A dog presents with regurgitations. On plain radiographs, there is evidence of pneumomediastinum (=free air in mediastinum). To rule out esophageal perforation, you would perform a ___ using ___
positive contrast esophagram
non-ionic iodinated
