CONTRAST AGENTS Flashcards
“Contrast media”
• Substances that have a higher or lower atomic number
• Taken orally or injected intravenously
CONTRAST AGENTS
Categories of Contrast media
iodine based
barium based
negative contrast
Dense chemical that is taken orally or intravenously.
IODINE BASED
2 types of iodine based
• IONIC CM
• NON-IONIC CM
Electrically negative charge acids containing iodine that ionize in solution and cause more patient discomfort.
IONIC CONTRAST MEDIA
Does NOT ionize in solution and is safer, less painful, and better tolerated by the patient
NON-IONIC CONTRAST MEDIA
A contrast medium in the radiography of the digestive tract because adverse effect it on has no the body and because of its high atomic number of 56.
BARIUM BASED
• Having a lower atomic number than the surrounding tissues and appear black on the radiograph.
• Air, carbon dioxide, & oxygen
NEGATIVE CONTRAST
IMPORTANT FACTORS IN SELECTING CONTRAST MEDIUM:
• It must be non-toxic and must be safe
• It must produce adequate contrast
• It must have a suitable viscosity
• It must have a suitable persistence
Method of introducing sensitivity testing
scleral method
sublingual
intradermal method
intravenous method
One drop of CM is put into the sclera of the eye.
SCLERAL METHOD
One drop of CM is deposited into the inferior base of the tongue
sublingual method
Icc of CM is injected just beneath the skin
intradermal method
Icc of CM is injected just into the vein
intravenous method
beam attenuation characteristics
radiolucent contrast agents (negative)
radiolucent contrast agents (positive)
medical history
allergies
treatment and occupation
time of the day
route of administration
• Produce areas of increased radiodensity
• Images appear DARK / BLACK
• They include air, gas-producing tablets. or soda water (CO2).
RADIOLUCENT CONTRAST AGENTS (NEGATIVE)
• HIGH atomic numbers
• Produce areas of decreased radiodensity
• Images appear light/white
• Include barium sulfate (BaSO4), as well as water-soluble and oil-based iodinated contrast media
RADIOLUCENT CONTRAST AGENTS (POSITIVE)
• Influences drug dosage
• People who take drugs frequently and in large quantities are less sensitive to them than those who rarely or never use them
MEDICAL HISTORY
may range from mild hypersensitivity to severe, life-threatening anaphylactic shock and may result from any anti-infective drug.
Allergies
A person’s temperament and occupation may also influences his reaction
TREATMENT & OCCCUPATION
A drug given in the morning when a patient is well rested may not be as effective as it might be later in the day.
TIME OF THE DAY
• Intravenous drug are immediately absorbed into the blood stream and circulated to all parts of the body
• Oral drugs are absorbed more slowly
ROUTE OF ADMINISTRATION
The blood vessel walls consist of three relatively distinct tissue layers:
I. TUNICA INTIMA
2. TUNICA MEDIA
3. TUNICA ADVENTITIA
Most internal layer of a blood vessel wall.
TUNICA INTIMA
