Unit 3 (Contrast)
Home > Flashcards > Print Preview
The flashcards below were created by user
on FreezingBlue Flashcards
. What would you like to do?
what was the very first contrast used, and when was it first used, and on what?
- cinnabar, vaseline, and gypsum
- one month after xray discovered (1985)
- on an amputated hand
what was the second noted contrast used (after the amputated hand in 1895), on what, and when?
- iodine contrast in an inorganic form (sodium iodide), which was toxic
- used on humans to make urine radiopaque
- 1923 (30 yrs after first contrast)
what was the third noted contrast used (after the toxic sodium iodide), and when?
- a safe intravascular water-soluble contrast
four routes of contrast media introduction:
- area with direct connection to outside of body: GI, genitourinary, respiratory
- bloodstream: liver (CT), kidney
- directly in vessels: angiogram
- cavities w/ no connection to the outside: joint spaces, bile ducts
what is the factor which determines whether a technologist is permitted to perform venipuncture for the administration of contrast media?
state statutes and institutional policy
who determines that the administration of contrast materials and radiopharmaceuticals is a responsibility of a registered technologist?
- ACR - American College of Radiology
- (1987 Resolution #27)
give examples of some radiolucent/negative contrast agents:
- CO2 (gas crystals)
- the normally present gas bubble
give some facts about CO2 as a contrast agent:
- available in small cartridges for individual use
- available in pressurized cylinders for departmental use (ex. BEs)
- it is absorbed in the body much faster than the nitrogen in the room air
name common sources used to produce CO2 gas:
calcium and magnesium citrate carbonate crystals
give two main forms of radiopaque contrast media (ROCM)
- aqueous agents (ionic, non-ionic, iodinated oral agents for GI tract)
- non-aqueous agents (barium, ethiodized oils)
have __________ as the principle solvent
consists of most ___________ contrast agents
Non Aqueous agents:
______________ as the principle solvent
- does not have water
pertaining to treatment introduced into the body other than through the digestive system:
within the small intestine, or via the small intestine:
name two common radiopaque contrast medias and give their atomic number and mass:
- barium: Z#56, atomic mass 137.33
- iodine: Z#53, atomic mass 126.9
what is the most common gastrointestinal radiopaque contrast? describe it.
- barium sulfate
- non-aqueous, relatively inert, chemically pure
when barium is mixed with water it forms a _____________, not a _______________.
- colloidal suspension
- (hygroscopic in nature)
name three aqueous iodinated contrasts for the GI tract (trade and generic names):
- gastrografin: diatrizoate meglumine and diatrizoate sodium
- hypaque sodium oral powder: diatrizoate sodium
- MD gastroview: diatrizoate meglumine and diatrizoate sodium
how is water-soluble iodinated contrast for the GI tract different from Barium?
- used when pt is to have surgery
- used if there is a risk of impaction
- used for neonatal studies
- used for suspected rupture of GI tract
- used if there's a perforated ulcer
- used if there is a rupture of the appendix
- it is very bitter
- is more expensive
- produces less radiographic contrast
- can cause serious dehydration/hazardous if aspirated
describe some key points concerning oral cholecystopaques:
- taken by mouth, demonstrate the biliary
- binds with albumin in blood, so can only be excreted by liver (not kidney)
- bilirubin levels need to be checked prior to using
name some common cholecystopaques:
- telepaque - iopanoic acid
- oragrafin - sodium or calcium ipodate
- cholebrine - iocetamic acid
describe some key points concerning ethiodized oils:
- used when it is undesirable for contrast to mix with blood, body fluids, or be absorbed
- greater risk of embolism
- high persistence
- low miscibility
- tend to decompose when exposed to air, heat, light
- clear, pale amber, or yellow in color
- inflammation may occur with extravasation
name some common ethiodized oils (oily agents):
name some procedures that require an oil based contrast:
- lymphography (primary use)
with what instrument should oily contrast agents be administered?
aqueous agents have a ________ miscibility factor and a ________ persistency factor than oily agents.
the _________ the persistence, the ________ the contrast is eliminated from the body.
- lower, faster
- higher, slower
two categories of intravascular iodinated contrast:
- (both are aqueous and contain iodine)
a contrast media category that is composed of carbon-based organic materials:
aqueous iodine contrast media
ROCMs used for roentgenography are derivitives of the ________________ molecule, with the exception of ___________.
- triodinated benzoic acid
it is the ________________ that absorbs the photons, not allowing them to pass through to the film, therefore leaving a silhouette of the structure it is in.
in an aqueous iodine contrast media, a positive side chain is added to the molecule called a(n) _________ which is a __________________. they increase the ___________ of the contrast.
- salt, usually sodium or meglumine or both
_________ contrast exist in salt form.
_________ contrast exist in non-salt form.
common anions in aqueous iodine solutions are:
- diatrizoate (hypaque)
- iothalamate (conray)
- metrizoate (isopaque)
- help stabilize the contrast by joining to the cation molecule
name some common intravascular ionic media:
- conray: iothalamate meglumine (high osmolality)
- hypaque: diatrizoate meglumine and/or diatrizoate sodium (high osmolality)
- hexabrix: sodium meglumine ioxaglate (low osmolality)
- cystografin: diatrizoate meglumine (high osmolality)
- MD-76: diatrizoate meglumine and diatrizoate sodium
- renografin-60: diatrizoate meglumine and diatrizoate sodium
name some common intravascular nonionic media:
- imagopaque: iopentol
- iomeron: iomeprol
- isovue: iopamidol
- omnipaque: iohexol
- optiray: ioversol
- visipaque: iodixanol
contrast media whose molecules disassociate into two charged particles called the cation (+) and the anion (-) are considered to be __________, while media whose molecules remain whole in the solution are ___________.
the movement of water across a semipermeable membrane:
_________ osmotic substances, such as ROCMs, placed into the bloodstream will cause fluid from ____________________ to be drawn _____________________.
- outside the bloodstream (extravascular)
- into the bloodstream (intravascular)
the concentration of molecules per weight of water:
has greater osmolality than body fluids:
has lower olsmolality than body fluids:
has equal osmolality to body fluids:
the ___________ the osmolality of a contrast medium is to the osmolality of body fluids, the ___________ potential there is for adverse reactions caused by differences in osmolality
- closer, less
- farther, more
____________ compounds cause more direct endothelial damage:
ionic contrast has a ________ osmolality than nonionic contrast, and this ___________ the risks of adverse side effects.
high osmolality ionic contrast media have _______ iodine atoms per molecule.
the ratio of the iodine atoms to particles with higher osmolality is _______ or a ratio media of ________.
compounds that contain more iodine atoms per molecule have _____ osmolality.
low osmolality ionic contrast media have ________ iodine atoms per molecule.
the ratio of the iodine atoms to particles with less osmolality is ________ or a ratio media of __________.
low osmolality nonionic contrast media have _______ iodine atoms per molecule.
- (and do not dissociate in solution)
with low osmolality nonionic contrast media, there is a ratio of iodine to osmoticaly active particle of _______ or a ratio media of _______.
when the ratio of particles to iodine atoms is low, there indicates a(n) __________ in osmolality.
- (which increases the risk of adverse side effects)
three characteristics of contrast that may vary:
- iodine concentration
the higher the concentration of iodine, the _______ attenuation of the beam and the _______ degree of positive contrast.
iodine concentration usage depends on:
the degree by which the contrast will be diluted by body fluids
the osmolality of human blood:
the osmolality of aqueous contrast:
rapid fluid movement may cause:
resistance of fluid to flow:
amount of viscosity is determined by:
- number of particles
- size of particles
- attraction of particles
- amount of iodine
reactions are influenced by:
- physical properties
- iodine concentration
- total dose or volume of contrast
- rate or speed of injection
for the aorta, a _________ concentration is used and for the veins and smaller arteries, a __________ concentration is used.
as the concentration of iodine rises, name three other factors that also rise:
an IV would be a ___________ concentration, while a bolus would be a ___________ concentration.
if you increase the number of iodine atoms in the molecule and keep the same number of molecules, the concentration:
if you increase the number of iodine atoms in the molecule but decrease the number of molecules, the concentration:
stays the same
the higher the numerical value of the ratio, the ________ the osmolality for a given iodine
describe how nonionic contrast is different from ionic contrast:
- they are less toxic and less neurotoxic
- less likely to cause anaphylactic shock
- less heat and discomfort during injection
- used to be more expensive
both nonionic and ionic contrasts contain:
why are there less reactions when using nonionic contrast as compared to ionic contrast?
- less osmotic
- low iodine concentration
- injected more slowly
- (less reactions when injecting into an artery rather than a vein)
is a high iodine concentration more or less viscous?
how is viscosity determined?
- molecular size
- molecular concentration
- frictions of molecules in the solution
name three things affected by viscosity:
- flow rate
- injection time
- needle size
what helps to reduce viscosity?
warming the contrast to body temperature
name two common aqueous iodine compounds:
- diatrizoate meglumine
- diatizoate sodium
what is the difference between sodium salts and meglumine salts?
- sodium salts are more radiopaque
- meglumine salts are somewhat less toxic and more soluble in water, and more viscous
name two common high osmolar contrast agents (HOCAs):
high osmolar contrast agents (HOCAs) contain:
sodium and meglumine salts
name one of the first agents used in myelography and what it was replaced with:
- metrizamide (amipaque)
- replaced with hexabrix (meglumine ioxaglate)
name some low osmolality contrast agents (LOCAs):
- iopamidol (isovue, niopam)
- iohexol (omnipaque)
- ioversol (optiray)
is a severe allergic reaction, may end in cardiac arrest or respiratory arrest, and less often seizures:
Iodixanol (visipaque) is often the contrast of choice when patients have mild to moderate renal insufficiency:
- iodixanol (visipaque)
- for high risk patients
- it is isoosmolar
_______ osmolality agents are routinely used and _________ are used for high risk patients.
total volume is dependent on:
- type (ionic or nonionic)
- weight and age of pt
- anatomical structure
- speed of injection
minimum amount of iodine needs to be given in order to have a satisfactory contrast enhancemnt of vascular stuctures and various tissues:
factors affecting flow:
- catheter/needle diameter and length
a study of the effects of drugs on the normal physiological function of the body; how a drug or contrast agent acts on the living system:
the study of the preparation properties, uses, and the actions of drugs:
the ________________ is sensitive to increased ions in the blood.
central nervous system
normal responses to ionic media:
- sensation of warmth
allergic or anaphylactoid responses are caused by:
- a release of histamine
- (suggested that this is a CNS response)
the result of interactions between the contrast medium and the blood, causing the suppression of certain enzymes:
the study of how drugs enter the body, are absorbed, reach their site of action, are metabolized, and exit the body:
name a diabetic medication that can be contraindicated after the administration of contrast media:
- metformin (glucophage)
- can cause acute renal failure
- withheld 48 hours after contrast administration
a chemical change that results in solid particles:
- (can cause a thrombus/stationary clot or embolus/moving blood clot)
name four incompatible medications known to cause precipitation when mixed with contrast:
- diaphenhydramine (benedryl): antihistamine
- papaverine HCl: smooth muscle relaxer
- cimetidine (tagement): inhibits gastric secretions
- protamine (protamine insulin): to neutralize the anticoagulant action of heparin
- (always flush IV before and after these)
be familiar with pre-contrast history items:
- history of renal failure
- history of diabetes
- history of glucophage if patient is a diabetic
- history of heart disease or high blood pressure
- contrast study performed within 48 hours
- history of allergy
- history of asthma
- previous allergic reaction to contrast medium
- note current medications
give normal BUN and creatinine levels:
- BUN: 8-25 mg/dl
- creatinine: 0.6-1.5 mg/dl
an increase in the diameter of blood vessels, which increases blood flow and lowers blood pressure:
dangers of overdose:
- repeat injection during arteriography
- multiple exams scheduled in various depts.
- change of doctor
what type of patient is three times more likely to have an anaphylactoid reaction?
what courses of action my be taken when a contrast study is scheduled for a high risk patient?
- exam canceled
- exam preceded by antihistamine or corticosteroid
- use of a nonionic contrast
minute amount of contrast injected intravenously, followed by a pause during which the patient is observed carefully:
reactions have occurred with as little as _______ of contrast.
signs of allergic reaction:
- restlessness and a sense of apprehension
- increased pulse rate
- pallor accompanied by weakness or a change in thinking ability
- cool, clammy skin or itching skin
- red rash, urticaria (hives)
- throat constriction
- dyspnea (shortness of breath)
- fall in blood pressure of 30 mm below the baseline systolic pressure
- NOTE: vomiting is a common reaction, not an allergic response
when a contrast is administered, how long must the patient be observed for signs of an allergic response?
for a PET/CT prep, the pt should be:
- no glucose in IV and/or NPO for 6 hours (water only)
- no sugar beverages for 24s
- no exercise 24 hours prior to study
- no chewing gum on day of study
- diabetic: blood glucose level less than 200 mg/dl and fast for 4 hours (eat and take insulin before beginning fast)
the medical abbreviation for four times a day:
the medical abbreviation for twice a day:
What would you like to do?
Home > Flashcards > Print Preview