Contrast media

Question 1

what organs display a low amount of subject contrast? (6)

Answer 1

stomach, kidney, liver, spleen, pancreas, and bowel

Question 2

what is subject contrast?

Answer 2

is the radiographic contrast caused by the difference in the composition of the patients body tissues

Question 3

what is subject contrast caused by?

Answer 3

the tissue differences, the anatomic number differences and the thickness of the patients body parts

Question 4

what 3 organ systems display a low subject contrast?

Answer 4

digestive, urinary and cerebrovascular

Question 5

what parts of the stomach and intenstine can you see on plain films?

Answer 5

fundus of the stomach due to the gastric bubble and any part in the large intestine that has fecal matter or gas

Question 6

what is contrast media?

Answer 6

are diagnostic agents that are introduces into the body orifices or injected into the vascular system, joints and ducts to enhance subject contrast in anatomic areas where low subject contrast exists

Question 7

what does the contrast media depend on? (2)

Answer 7

the anatomic number of the element used in a particular medium and the concentration of atoms of the element per volume of medium

Question 8

what are the 3 types of contrast media?

Answer 8

1. radiolucent (negative) contrast agents
2. radiopaque (positive) contrast agents
3. speciality contrast agents

Question 9

what are the MRI contrast agents?

Answer 9

gadolinium diethylenetrianminepentaacetic acid (DTPA)–metalic and magnetic agent that affects signal intensity

Question 10

how do ultrasound enhance subject contrast?

Answer 10

gas filled microcmubbles that affect the sound wave to enhance ultrasound contrast

Question 11

what are the physical properties of negative contrast agents?

Answer 11

-composed of elements with low atomic numbers and decrease the attenuation of the x-ray beam

Question 12

negative contrasts can be administered by 2 way?

Answer 12

gas (air) and carbon dioxide (tablets, crystals, soda water)

Question 13

what kind of density does the negative contrast agents produce?

Answer 13

increased density, as more x-rays reach the film the structure that is filled with negative contrast agents appear black on the radiograph

Question 14

what kind of air is the most common negative contrast agent?

Answer 14

room ari- the air in the lungs serve as a negative contrast medium on the chest radiograph

Question 15

what is a double contrast effect?

Answer 15

when a negative agent may be combined with a positive contrast agent

Question 16

what kind of agent is barium?

Answer 16

positive contrast agent

Question 17

what kind of contrast agent must never been injected intravenously? why?

Answer 17

negative, can cause serious or fatal affects

Question 18

what are positive contrast agents composed of?

Answer 18

elements with high atomic numbers

Question 19

how do positive contrast agents appear on a radiograph?

Answer 19

absorb more x-rays and appear bright

Question 20

how much more x-rays do positive agents absorb than bone? soft tissue?

Answer 20

bone about 3 times, and 5 times more than soft tissue

Question 21

what are 2 types of positive contrast agents?

Answer 21

barium (56) & iodine (53)

Question 22

what is the atomic number of barium?

Answer 22

56

Question 23

what is the atomic number of iodine?

Answer 23

53

Question 24

what is the atomic number of soft tissue?

Answer 24

7.4

Question 25

what is the atomic number of gadolinium?

Answer 25

64

Question 26

2 types of iodinated compounds?

Answer 26

water soluble and oil based

Question 27

what is barium sulfate used for?

Answer 27

inert power composed of crystals that is used for examination of digestive system

Question 28

what is the chemical equation for barium?

Answer 28

BaSO4- one atom of barium to one atom of sulfur to 4 atoms of oxygen

Question 29

the mixture of barium and water forms?

Answer 29

colloidal suspension--never dissolves in water

Question 30

what is flocculation?

Answer 30

when powder clumps and come out of suspension

Question 31

what are used to prevent flocculation?

Answer 31

stabilizing agents?

Question 32

what are the stabilizing agents?

Answer 32

sodium carbonate and sodium citrate

Question 33

what does enteral mean?

Answer 33

within, or by way of, the intestine or gastrointestinal tract

Question 34

why can't barium be used intravascularly or intrathecally

Answer 34

because of its inability to be absorbed by the body

Question 35

what is intrathecal?

Answer 35

introduced into or occurring in the space under the arachnoid membrane of the spinal cord or brain

Question 36

what are the adverse reactions of barium? (6)

Answer 36

barium in the appendix, sedated patient, allergic reactions, hypervolemia, vaginal rupture, extravasation, and obstruction/constipation

Question 37

what is extravasation?

Answer 37

leakage from a vessel into the tissue

Question 38

what can extravasation lead to?

Answer 38

peritonitis

Question 39

who is prone to extravasation after barium?

Answer 39

elderly, long term steroid patients, patients with diverticulitis and ulcerative colitis

Question 40

what is a vaginal rupture?

Answer 40

rare complication of barium sulfate administration, it is due to the misplacement of the catheter before lower GI examinations--you should ask female patients if they feel enema tip in the rectum

Question 41

what is hypervolemia?

Answer 41

a blood disorder consisting of an increase in the volume of circulating blood --this can occur when water from the cleansing enema or barium enema is shift from the colon to the circulatory system resulting increase blood volume

Question 42

what are the consequences of hypervolemia?

Answer 42

edema, seizures, coma or death

Question 43

what is added to barium by manufacturer to reduce the possibility of hypervolemia

Answer 43

table salt

Question 44

what atomic number does iodine have?

Answer 44

53

Question 45

what would oiled based contrasts be used for?

Answer 45

lymphangiograms and bronchograms

Question 46

what were oil based contrast used for in the past?

Answer 46

myelograms, bronchograms, hysterosalpingograms, sialograms and dacryocystograms

Question 47

what has replaced oil based contrasts

Answer 47

water soluble iodinated contrast media

Question 48

what kind oil based or water soluble should not be injected intravenously?

Answer 48

oil based- not miscible with blood

Question 49

what is miscible?

Answer 49

capable of being mixed together

Question 50

what are oil based medias made from?

Answer 50

fatty acids

Question 51

what is a two carbon atom chemical group called

Answer 51

ethyl group

Question 52

what is viscous?

Answer 52

of a liquid, not pouring freely, having the consistency of syrup or honey

Question 53

what is insoluble?

Answer 53

not soluble, unable to dissolve

Question 54

what is the main disadvantage of oil based iodine?

Answer 54

they persist in the body because they are water soluble

Question 55

what is anaphylactic shock?

Answer 55

is the result of an exaggerated hypersensitivity reaction to an antigen that was previously encountered by the body immune system

Question 56

what is the most common cause of anaphylaxis ?

Answer 56

iodinated contrast agents

Question 57

water soluble contrast may be described as either?

Answer 57

ionic iodinated contrast media or nonionic iodinated contrast media

Question 58

what long does it take the body (kidneys) to excrete the water soluble contrast?

Answer 58

24 hours

Question 59

What is osmolslity

Answer 59

Refers to the concentration or number of particles in the solution per kg of water and is directly related to the occurrence of adverse reactions

Question 60

What is hypervolemia?

Answer 60

A blood disorder consisting of an increase in the volume is circulating blood