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RT 214 > Midterm| Intro to CM > Flashcards

Midterm| Intro to CM Flashcards

1
Q

Substances used in medical imaging to enhance visiblity of internal structures

A

Contrast Media/ Contrast Agent

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2
Q

Lead substrate was used to study the digestive system of the guinea pig which later proved to be toxic

A

1896

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3
Q

Walter Cannon used bismuth subnitrate in his series of experiments to study the digestive system. (Geese, cats, and 7y/o girl)

A

1896

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4
Q

Articles about the advantages of the inert and insoluble compound barium sulfate began to appear in the medical literatures. Its use increased rapidly because of its lack of toxicity, low cost, and availability

A

1910

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5
Q

Walter Dandy, a neurosurgeon, injected air to study the cerebral ventricles of children with hydrocephalus

A

1918

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6
Q

Water soluble ionated CM were introduced by Edgar Moniz. He injected sodium iodide into the cerebrovascular circulation by way of the carotid arteries.

A

1927

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7
Q

Atoms with high atomic numbers, such as iodine, could be placed on nontoxic water-soluble carrier molecules

A

1930

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8
Q

The degree of attenuation of an X-ray beam by an element is complex, but one of the major variables is the (1) in the path of the beam with which it can interact.

A

number of electrons

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9
Q

The number of electrons in the path of the beam is dependent upon three factors:

A
  1. Thickness of substance being studied
  2. Its density
  3. Number of electrons per atom of the element (which is equal to its atomic number)
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10
Q

CM are agents that are instilled into (1) or injected onto the (2) to enhance (3) in anatomic areas where low subject contrast exists.

A
  1. body orifices
  2. vascular system joints and ducts
  3. subject contrast
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11
Q

CM Types

A

Positive
Negative

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12
Q

Negative CM Mechanism of Action

A

Allows XR to pass through more easily compared to surrounding tissues resulting in darker appearances

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13
Q

Composed of low atomic number elements

A

Negative CM

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14
Q

Administered as gas or gas producing tablets, crystal or soda water, Air, carbon dioxide, oxygen

A

Negative CM

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15
Q

Why is negative CM rarely used alone as contrast agent

A

— Limited visibility: doesn’t provide enough detail to effectively visualize structures
— Less contrast differentiation: may not create strong enough differences b/n various tissues making it harder to identify abnormalities
— Pt preparation: Often requires careful pt preparation and specific positioning which can comoplicate its use as a standalone agent

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16
Q

Usually outlines soft tissue

A

Negative CM

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17
Q

Absorb less radiation, resulting in negative contrast or dark shadows.

Being lighter, they absorb fewer x-rays compared to soft tissues.

A

Air and gases

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18
Q

— provide a distinct outline of the surrounding tissues, which appear in lighter shades of gray

A

Air-filled cavities

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19
Q

Gases used for radiographic contrast must be (1) and (2) by the body

A
  1. non-toxic
  2. easily absorbed
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20
Q

CO2 meets these requirements and is preferred for its (1) compared to nitrogen.

A
  1. faster absorption
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21
Q

Available in small cartridges for individual use or in large, pressurized cylinders.

A

CO2

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22
Q

In the past, gas was injected into the spinal canal to visualize the (1). Procedure is called (2)

A
  1. brain’s ventricles
  2. Pneumoencephalography
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23
Q

Characteristics of CO2

A

— low Z
— safety: naturally occuring gas generally well-tolerated by pt; has low risk of allergic rx and is less likely to cause complication than other ionated CM
— reduces risk of nephrotoxicity: does not pose risk to kidney functions
— effective visualization
— ease of use: easily administered via specific delivery systems allowing for precise control over amount use and area being damaged
— rapid administration: thru respiration

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24
Q

Normal creatinine level

A

0.7 - 1.3

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25
Q

System for automatic CO2 injection in angiography

A

Angiodroid

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26
Q

Usually used for insufflation in GI procedures; can also be involved in imaging contexts

A

E-Z EM CO2 Insufflator

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27
Q

Ppositive CM Mechanism of Action

A

Higher density than surrounding tissues, leads to greater absorption of XRs, makes the areas appear lighter

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28
Q

Ppositive CM examples

A

Barium sulfate
Iodinated contrast

29
Q

Iodine and Barium Atomic number

A

Iodine: 53
Barium: 56

30
Q

TYPES OF POSITIVE CM COMPOUNDS

A
  1. Metallic Salts
  2. Organic Iodide
31
Q

After Roentgen’s discovery of X-rays, improving image contrast was essential for better clarity

A

Metallic Salts

32
Q

Elements with high atomic numbers were identified to enhance radiopacity in X-ray imaging.

A

Metallic Salts

33
Q

Initially used to develop the first angiogram on an amputated hand

These heavy metals were found to be unsafe for use in living patients

A

Barium salts
Bismuth
Lead

34
Q

An inert inorganic salt, now safely used for radiographic imaging of the GI tract.

It is administered either orally or rectally for GI studies

A

Barium Sulfate

35
Q

Main advantage:
- high quality images
- ulcer, tumor, bloackages in GI track visualization

A

Barium Sulfate

36
Q

Derived from iodine-containing organic compounds

A

Organic iodides

37
Q

Number of particles in solution per kilogram of water.

A

Osmolality

38
Q

It is responsible for the adverse effects of contrast media; risk is reduced when the this is lowered.

A

Osmolality

39
Q

Is a measure of the resistance of fluid to flow.

A

Viscosity

40
Q

Agents with — tend to be more viscous

A

high iodine concentration

41
Q

Main advantage:
- high contrast resolution
- rapid clearance (quickly excreted by kidneys)

A

Organic iodides

42
Q

Types of organic iodides

A

a. Oily CM/ Ethiodized oil
b. Water- soluble iodine compound

43
Q

These are specialized contrast agents that were developed for studies in which absorption of contrast into the surrounding tissues, or mixing of contrast with body fluids, is not desired.

A

Oily CM/ Ethiodized oil

44
Q

Principal use of ethiodized oil today

A

lymphography

45
Q

Injected directly into the lymphatic system typically through small incision near a lymph node or lymphatic vessel

A

Oily CM/ Ethiodized oil

46
Q

Most frequently used contrast agents

A

Water-soluble iodine compound

47
Q

These agents are carbon-based organic chemicals containing iodine atoms and various other elements.

A

Water-soluble iodine compound

48
Q

Water-soluble iodine compound osmolality range

A

300 mOsm/kg to over 1000 mOsm/kg

49
Q

Types of Water-soluble iodine compound

A
  1. Ionic Contrast Media/ High Osmolality CM (HOCM)
  2. Non-Ionic Contrast Media/ Low Osmolality CM (LOCM)
50
Q

Composed of iodinated benzoic acid derivatives

A

HOCM

51
Q

Historically relied upon for radiographic and CT imaging

A

HOCM

52
Q

Consists of a positively charged cation and a negatively charged anion, and they are strong acids that fully dissociate in solution.

A

HOCM

53
Q

Consists of a positively charged cation and a negatively charged anion, and they are strong acids that fully dissociate in solution.

A

HOCM

54
Q

Higher likelihood of allergic reactions

A

HOCM

55
Q

Significantly hyperosmotic to body fluids, which can lead to adverse effects, including cardiac events, vein cramping, pain, and abnormal fluid retention

A

HOCM

56
Q

Often utilized for angiography and urography

A

HOCM

57
Q

Examples of HOCM

A

Diatrizoate
Iothalamate

58
Q

Less concentrated, resulting in a lower incidence of allergic reactions, making it more expensive

A

LOCM

59
Q

Its osmolality is closer to that of human plasma at similar iodine concentrations, contributing to fewer adverse reactions

A

LOCM

60
Q

Has wide spread application

A

LOCM

61
Q

Examples of LOCM

A

Ionexol
Iopamidol
Ioversol

(Io-nex-vers-pam)

62
Q

Special contrast agent for MRI

A

gadolinium diethylenetriaminepentaacetic acid (gadolinium-DTPA)

63
Q

This CM is a metallic and magnetic agent that will affect the signal intensity used to image the anatomic area of interest

A

gadolinium diethylenetriaminepentaacetic acid (gadolinium-DTPA)

64
Q

CM for UTZ are usually — that affect the soundwave to enhance UTZ contrast

A

gas-filled microbubbles

65
Q

Positive and negative CM are used together

A

Double Contrast studies

66
Q

Coats the part under study

A

Positive CM

67
Q

Fills the space and permits vizualization through gaseous medium

A

Negative CM

68
Q

Mucosal liningare well visualized

A

Negative CM

RT 214 (7 decks)

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