Contrast media for the GIT Flashcards
What was early contrast media for the GIT and why was it not efficient?
- Iodized oil such as lipiodol, which was not efficient in mucosal coating due to its oily nature.
What is the current contrast media of choice for GI studies? A:
Barium sulphate (BaSO4).
Who first proposed BaSO4 for GIT examinations and when?
Bechem and Gunther in 1910.
What are the advantages of BaSO4 as contrast media for the GIT?
- Barium (Ba) has a high atomic number (56) and is highly radiopaque.
- Non-absorbable and does not get degraded throughout the bowels.
- Non-toxic in the GIT.
- Insoluble in water/lipid.
- Inert to tissues.
- Can be used for double contrast studies as it coats the mucosa in a thin layer
What is the average particle size of precipitated barium sulphate?
Ranges from 0.3 µm to ≈ 12 µm.
What properties should an ideal Barium preparation offer?
- High density for optimum study.
- Stable suspension that does not settle.
- Should not flocculate with secretions.
- Low melting characteristics for good and stable coating.
How is barium sulphate used in the form of a suspension?
It is insoluble in water and used in the form of a suspension with concentration indicated by weight/volume (w/v).
What are the three standardized systems for measuring the amount of BaSO4 in a liquid suspension?
- Weight by weight (w/w) suspension.
- Weight by volume (w/v) suspension.
- Volume by volume (v/v) suspension.
How is a 40% w/v suspension prepared?
By adding 40 grams of BaSO4 to enough water to make a total volume of 100 ml suspension.
How is a 40% w/w suspension prepared?
By adding 40 grams of BaSO4 to 60 grams (60 ml) of water to obtain a total weight of 100 grams.
Why is the volume by volume (v/v) suspension system not recommended?
Because a unit volume of dry BaSO4 can vary considerably depending on the degree of packing.
