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RT 208 > 5.1 Contrast Agents Part 1 > Flashcards

5.1 Contrast Agents Part 1 Flashcards

1
Q

Contrast Agents introduced in practice by ______,

a Urologist in _____

A

Moses Swick,

1928

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2
Q

Any substance that renders an organ or

structure more visible than is possible without its addition

A

Radiographic Contrast Media

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3
Q

Allows visualization of structures that
can not be seen well or at all under
normal circumstances

A

Radiographic Contrast Media

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4
Q

Substances which help in better

differentiation between adjacent tissues

A

Radiographic Contrast Media

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5
Q

Substances which increase beam

attenuation

A

Radiographic Contrast Media

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6
Q

Contrast media is needed because:
Soft tissue has a ____
absorption/interaction ratio

A

low

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7
Q

Absorption is dependent on

A
  • atomic number
  • atomic density
  • part thickness
  • K-shell binding energy (K-edge)
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8
Q

is the process of absorption

A

Photoelectric Interaction

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9
Q

An oral or intravenous administration of a contrast agents is often used to create a _______ between objects

A

temporary, artificial density difference

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10
Q

Goal of Contrast Agent

A

To give different tissues, which would ordinarily have similar attenuations, different attenuation coefficients making them more readily visible on the image

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11
Q

Types of Contrast Media

A
  • Radiopaque/Positive Agent
  • Radiolucent/Negative Agent
  • Neutral Agents
  • Radionuclides
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12
Q

Higher density than the tissue and absorbs radiation

A

Radiopaque/Positive Agent

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13
Q

Contrast agent appears more radiopaque (white) than surrounding tissues

A

Radiopaque/Positive Agent

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14
Q

High atomic number

A

Radiopaque/Positive Agent

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15
Q

Radiopaque/Positive Agent examples

A

Barium Sulfate and Iodinated (soluble)

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16
Q

Lower density than the surrounding tissue

A

Radiolucent/Negative Agent

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17
Q

Decrease density

A

Radiolucent/Negative Agent

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18
Q

Low atomic number

A

Radiolucent/Negative Agent

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19
Q

Organs with contrast agent becomes more radiolucent than surrounding tissues

A

Radiolucent/Negative Agent

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20
Q

X-rays penetrate more easily

A

Radiolucent/Negative Agent

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21
Q

Radiolucent/Negative Agent examples

A

Air and Carbon Dioxide

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22
Q

GI agents possess a density similar to water

A

Neutral Agents

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23
Q

Appears similar to surrounding tissues

A

Neutral Agents

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24
Q

Neutral Agents example

A

Water, VoLumen

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25
Q

low density form of barium sulfate suspension

A

VoLumen

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26
Q

emits radiation

A

Radionuclides

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27
Q

used in nuclear medicine

A

Radionuclides

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28
Q

Common Route of Administration

A
  • Intravascular

- Gastrointestinal

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29
Q

Less Common Route of Administration

A
  • Intrathecally

- Intraarticularly

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30
Q

subarachnoid space surrounding the spinal cord

A

Intrathecally

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31
Q

directly into a joint space

A

Intraarticularly

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32
Q

universally used for a variety of radiology examinations

A

Iodinated Agents

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33
Q

Iodinated Agents

A
  1. Water soluble
  2. Easy to administer intravascularly
  3. Have a high safety index
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34
Q

has high attenuation compared with human soft tissue, therefore, wherever it distributes it increases the ability of the enhanced structure to attenuate the x-ray beam

A

Intravascular Contrast Media

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35
Q

two tissues must differ by at least ___ Hounsfield units (HU) to be visibly different on a CT Scan

A

10

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36
Q

Proper administration of contrast media can easily provide a ___ HU increase in the natural difference of attenuation between tissues, thus making them visibly different in the image

A

40-75

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37
Q

Hounsfield Units of Bone

A

1000

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38
Q

Hounsfield Units of Liver

A

40 to 60

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39
Q

Hounsfield Units of White Matter

A

46

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40
Q

Hounsfield Units of Grey Matter

A

43

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41
Q

Hounsfield Units of Blood

A

40

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42
Q

Hounsfield Units of Muscle

A

10 to 40

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43
Q

Hounsfield Units of Kidney

A

30

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44
Q

Hounsfield Units of Cerebrospinal Fluid

A

15

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45
Q

Hounsfield Units of Water

A

0

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46
Q

Hounsfield Units of Fat

A

-50 to -100

47
Q

Hounsfield Units of Air

A

-1000

48
Q

are not used for their therapeutic qualities, but rather for their distribution and elimination from the body

A

Iodinated agents

49
Q

____ of CM differs from other pharmaceuticals

A

Dose and delivery

50
Q

Iodinated agent example

A

Morphine Sulfate

51
Q

Morphine Sulfate

A

2 to 10 mg diluted in 5 - 15 mL of sterile water

Given at regular intervals of 4 hours

52
Q

iodinated contrast agents

A

Bolus injection

53
Q

Bolus injection

A

100 to 150 mL in less than 1 min

54
Q

have nearly the same number of particles in solution per unit of liquid as blood

A

Isotonic

55
Q

the structural property of a liquid regarding the number of particles in solution, per unit liquid, as compared with blood

A

Osmolality

56
Q

Osmolality unit

A

milliosmoles per kg (mOsm/kg) of water

57
Q

290 mOsm/kg water

A

Blood plasma

58
Q

4-7x the osmolality of blood

A

High-osmolality Contrast Media (HOCM)

59
Q

2-3x the osmolality of blood

A

Low-osmolality Contrast Media (LOCM)

60
Q

same osmolality as blood

A

Isosmolar Contrast Media (IOCM)

61
Q

most brands of iodinated CM have a greater osmolality than blood plasma, therefore most CM are said to be

A

hyperosmolar/hypertonic solution

62
Q

older iodinated CM

A

HOCM

63
Q

1,300 - 2,140 mOsm/kg

A

HOCM

64
Q

Year of LOCM

A

1980’s

65
Q

600-850 mOsm/kg

A

Low-osmolality Contrast Media

66
Q

Year of IOCM

A

1996

67
Q

osmolality equal to blood

A

IOCM

68
Q

more expensive than LOCM

A

IOCM

69
Q

example of IOCM

A

Visipaque

70
Q

offer some advantages for patients at risk of renal complications

A

IOCM (Visipaque)

71
Q

Year of HOCM

A

less than 1980’s

72
Q

plays a major role in nonalleregic reactions to CM

A

Osmolality

73
Q

a bolus injection of a hypertonic contrast agent causes a _____ in the osmolality of the plasma

A

rapid increase

74
Q

The ____ the agent’s osmolality, the more pronounced the effects of this increase

A

higher

75
Q

physical property that may be described as the thickness or friction of the fluid as it flows

A

Viscosity

76
Q

an important quality that will influence the injectability of intravascular agents through small-bore needles and intravenous catheters

A

Viscosity

77
Q

affects viscosity

A

Molecular structure and concentration

78
Q

different brands of iodinated contrast media will possess ___ viscosities

A

varying

79
Q

Increase Iodine Content, ____ Viscosity

A

Increases

80
Q

intravascular contrast agents can be classified as to whether the molecules they contain will separate into charged particles (i.e., ions) when dissolved in an aqueous solution

A

Ionicity

81
Q

will dissociate into ions when in solution

A

Ionic contrast agents

82
Q

do not dissociate

A

Nonionic contrast media

83
Q

Although most nonionic contrast also have low osmolality, the two terms are not ____

A

synonymous

84
Q

An ____, may be ionic

A

LOCM

Ex. Hexabrix

85
Q

once injected, all types of iodinated contrast media undergo very rapid distribution throughout the entire extracellular space

A

Clearance

86
Q

iodinated contrast media has a half-life approx. ____

A

2 hrs.

87
Q

powder, dissolves in water, oral or rectal, cheaper

A

Barium Sulfate

88
Q

liquid, oral or IV, for pediatric patients

A

Iodinated Contrast Media

89
Q

oral contrast media is excreted through

A

Defecation

90
Q

IV contrast media is excreted through

A

Urination

91
Q

Iodinated contrast media excreted by _____ via _____

A

kidney,

via glomerular filtration

92
Q

not metabolized

A

Iodinated contrast media

93
Q

number of particles in solution

A

Osmolality

94
Q

described as the thickness or friction of the fluid as it flows

A

Viscosity

95
Q

structural property of intravascular CM

A

Osmolality

96
Q

physical property of intravascular CM

A

Viscosity

97
Q

molecules that will form ions

A

Ionic

98
Q

not synonymous with LOCM

A

Ionic

99
Q

molecules do not dissociate

A

Nonionic

100
Q

Normal renal function (CM clearance)

A

2 hours though kidney via glomerular filtration

101
Q

consider the iodine concentration and the volume

A

Dose

102
Q

is directly related to the concentration of iodine

A

Beam attenuation abilities

103
Q

measured in mg of iodine per mL (mgI/mL) of solution

A

LOCM

104
Q

LOCM examples

A
  • Iopamidol (isovue)
  • Iohexol (omnipaque)
  • Iopromide (ultravist)
  • Ioversol (optiray)
  • Ioxilan (oxilan)
105
Q

are labeled in terms of their percent weight per volume

A

HOCM

106
Q

HOCM examples

A
  • Diatrizoate sodium/meglumine (Gastrogafin, MD-Gastroview, Cystografin)
  • Iothalamate sodium/meglumine (Cconray, Cysto-Conray)
107
Q

Total Iodine Delivered

A

Volume (mL) x Iodine Concentration (mg I/mL)

108
Q

The combination of volume and concentration to be used should be individualized accounting for factor such as:

A
  • age
  • body weight
  • the size of the vessel into which it will be injected
109
Q

Other factors include:

A
  • anticipated pathology
  • degree and extent of opacification required
  • structure(s) or area to be examined
  • disease processes affecting the patient
  • the specific equipment available
110
Q

CT examinations perform on pediatric patient is calculated by ____

A

weight

111
Q

most common formula for pediatric patients

A

2 mL per kg

112
Q

the quality of examinations are the ______

A

same, or better when a weight-based protocol is used

113
Q

an example of a weight-based calculation for routine body scanning is 1.5 mL/kg (not to exceed ____)

A

200 mL

114
Q

there is no proof that contrast agents present a risk to the ____. However, there is not evidence to be certain they pose no risk

A

fetus

RT 208 (16 decks)

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