Contrast Media

Question 1

define contrast media

Answer 1

substances that increase radiographic contrast in an area of typically low contrast

Question 2

what are the 2 types of contrast media

Answer 2

radiolucent/negative agents - appear black on image - air, CO2
radiopaque/positive agents- appear white on image - contrast agents

Question 3

describe iodine agents

Answer 3

best contrast agents

can be administered orally or via IV

Question 4

describe barium agents

Answer 4

aka barium suphate
used for GI tract
orally and rectal administration possible
not absorbed significantly by GI
can cause GI side effects - drink water

Question 5

define non ionic vs ionic

Answer 5

non - remains whole (isnt broken down)

ionic - creates 2 ions in blood

Question 6

define osmolality

Answer 6

the ability of a liquid to give up or take on water from another liquid separated by a semipermeable membrane

Question 7

for contrast media what osmolality do we want? high or low?

Answer 7

low - specifically isomolar as that is the same as blood

Question 8

what are the 2 types of contrast solutions used by CCMB

Answer 8

visipaque (IV)

telebrix (oral)

Question 9

describe visipaque

Answer 9

intravenous
nonionic
iodine content -320mg/ml
osmolality - 290 (isomolar)

Question 10

describe telebrix

Answer 10

orally taken
ionic solution
iodine content - 768mg/ml
osmolality - 2100 (high)

Question 11

list some types of non-injected contrast

Answer 11

oral
rectal
cystogram - inbladder
cervix - tampon soaked with contrast

Question 12

define viscosity

Answer 12

the thickness or resistance to flow of a liquid

Question 13

what does viscosity have to do with injection rate

Answer 13

higher viscosity = slower injection rate (due to resistance)

fyi - heat can improve viscosity (easier to inject = low)

Question 14

is IV contrast metabolized

Answer 14

nope

Question 15

how is IV contrast excreted

Answer 15

filtered through kidneys excreted via urine

Question 16

why are power injectors necessary

Answer 16

scan times are short and contrast can move through blood quickly
therefore constant administration is needed
it is very difficult to administer manually due to viscosity

Question 17

what are the risks of power inectors

Answer 17

extravasion and air emboli

Question 18

what are the symptoms of extravasion

Answer 18

pain, swelling @ injection site

Question 19

what are some ways to prevent extravasion

Answer 19

feel injection site after initial injection

keep canulla minimum 20G

Question 20

what are some symptoms of air emboli

Answer 20

stroke

usually undetected tho and get absorbed quickly

Question 21

what is a way we can prevent air emboli

Answer 21

inspect tubing for air bubles

Question 22

what vein is commonly used for power injector, why is it used

Answer 22

vein of antecubital fossa - cephalic and basilic
large and easily palpable
** can accept the pressure of the power injector

Question 23

list 3 venipuncture equipment

Answer 23

catheter - soft, pliable with blunt end, attached to hub
stylet - AKA trocar, metal, with beveled tip + flash back chamber to fit inside catheter
protective cap - covers catheter and hub

Question 24

what is the main implication of contrast media with tx planning

Answer 24

sims imaging involves a 1:1 ratio between CT numbers and density
therefore by administering contrast this ratio is not true
this creates a level of uncertainty when it comes to the path of the photon beam through the structures