Unit 3 (Contrast)

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Unit 3 (Contrast)
2013-03-03 19:29:56
Procedures IV

Unit 3: contrast
Show Answers:

  1. 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
  2. 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)
  3. what was the third noted contrast used (after the toxic sodium iodide), and when?
    • a safe intravascular water-soluble contrast
    • 1950
  4. 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
  5. 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
  6. 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)
  7. give examples of some radiolucent/negative contrast agents:
    • oxygen
    • CO2 (gas crystals)
    • air
    • nitrogen
    • hydrogen
    • helium
    • the normally present gas bubble
  8. 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
  9. name common sources used to produce CO2 gas:
    calcium and magnesium citrate carbonate crystals
  10. 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)
  11. Aqueous agents:
    have __________ as the principle solvent
    consists of most ___________ contrast agents
    __________ miscibility
    __________ viscosity
    • water
    • iodinated
    • high
    • low
  12. Non Aqueous agents:
    ______________ as the principle solvent
    __________ miscibility
    __________ viscosity
    • does not have water
    • low
    • high
  13. pertaining to treatment introduced into the body other than through the digestive system:
  14. within the small intestine, or via the small intestine:
  15. 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
  16. what is the most common gastrointestinal radiopaque contrast? describe it.
    • barium sulfate
    • non-aqueous, relatively inert, chemically pure
  17. when barium is mixed with water it forms a _____________, not a _______________.
    • colloidal suspension
    • solution
    • (hygroscopic in nature)
  18. 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
  19. 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
  20. describe some key points concerning oral cholecystopaques:
    • aqueous
    • 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
  21. name some common cholecystopaques:
    • telepaque - iopanoic acid
    • bilopaque
    • oragrafin - sodium or calcium ipodate
    • cholebrine - iocetamic acid
  22. describe some key points concerning ethiodized oils:
    • intravascular
    • 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
  23. name some common ethiodized oils (oily agents):
    • dionisil
    • ethiodol
  24. name some procedures that require an oil based contrast:
    • lymphography (primary use)
    • dacryocystography
    • hysterosalpingography(HSG)
    • sialography
    • fistulas
  25. with what instrument should oily contrast agents be administered?
    glass syringe
  26. aqueous agents have a ________ miscibility factor and a ________ persistency factor than oily agents.
    • higher
    • lower
  27. the _________ the persistence, the ________ the contrast is eliminated from the body.
    • lower, faster
    • OR
    • higher, slower
  28. two categories of intravascular iodinated contrast:
    • ionic
    • nonionic
    • (both are aqueous and contain iodine)
  29. a contrast media category that is composed of carbon-based organic materials:
    aqueous iodine contrast media
  30. ROCMs used for roentgenography are derivitives of the ________________ molecule, with the exception of ___________.
    • triodinated benzoic acid
    • barium
  31. žit 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.
    iodine molecules
  32. 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.
    • cation
    • salt, usually sodium or meglumine or both
    • solubility
  33. _________ contrast exist in salt form.
    _________ contrast exist in non-salt form.
    • ionic
    • nonionic
  34. common anions in aqueous iodine solutions are:
    • ždiatrizoate (hypaque)
    • iothalamate (conray)
    • metrizoate (isopaque)
    • help stabilize the contrast by joining to the cation molecule
  35. 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
  36. name some common intravascular nonionic media:
    • imagopaque: iopentol
    • iomeron: iomeprol
    • isovue: iopamidol
    • omnipaque: iohexol
    • optiray: ioversol
    • visipaque: iodixanol
  37. žcontrast 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 ___________.
    • ionic
    • nonionic
  38. the movement of water across a semipermeable membrane:
  39. ž_________ osmotic substances, such as ROCMs, placed into the bloodstream will cause fluid from ____________________  to be drawn _____________________.
    • highly 
    • outside the bloodstream (extravascular)
    • into the bloodstream (intravascular)
  40. the concentration of molecules per weight of water:
  41. has greater osmolality than body fluids:
  42. has lower olsmolality than body fluids:
  43. has equal osmolality to body fluids:
  44. žthe ___________ 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
    • OR
    • farther, more
  45. ____________ compounds cause more direct endothelial damage:
  46. ionic contrast has a ________ osmolality than nonionic contrast, and this ___________ the risks of adverse side effects.
    • higher
    • increases
  47. high osmolality ionic contrast media have _______ iodine atoms per molecule.
  48. žthe ratio of the iodine atoms to particles with higher osmolality is _______ or a ratio media of ________.
    • 3:2
    • 1.5
  49. compounds that contain more iodine atoms per molecule have _____ osmolality.
  50. low osmolality ionic contrast media have ________ iodine atoms per molecule.
  51. the ratio of the iodine atoms to particles with less osmolality is ________ or a ratio media of __________.
    • 6:2
    • 3
  52. low osmolality nonionic  contrast media have _______ iodine atoms per molecule.
    • three
    • (and do not dissociate in solution)
  53. žwith low osmolality nonionic contrast media, there is a ratio of iodine to osmoticaly active particle of _______ or a ratio media of _______.
    • 3:1
    • 3.0
  54. when the ratio of particles to iodine atoms is low, there indicates a(n) __________ in osmolality.
    • increase
    • (which increases the risk of adverse side effects)
  55. three characteristics of contrast that may vary:
    • iodine concentration
    • osmolality
    • viscosity
    • toxicity
  56. žthe higher the concentration of iodine, the _______ attenuation of the beam and the _______ degree of positive contrast.
    • greater
    • greater
  57. iodine concentration usage depends on:
    the degree by which the contrast will be diluted by body fluids
  58. the osmolality of human blood:
    300 milliosmoles/kg
  59. the osmolality of aqueous contrast:
    600-1300 milliosmoles/kg
  60. rapid fluid movement may cause:
    • flushing
    • nausea/vomiting
    • dehydration
  61. resistance of fluid to flow:
  62. amount of viscosity is determined by:
    • number of particles
    • size of particles
    • attraction of particles
    • amount of iodine
  63. reactions are influenced by:
    • physical properties
    • iodine concentration
    • total dose or volume of contrast
    • rate or speed of injection
  64. for the aorta, a _________ concentration is used and for the veins and smaller arteries, a __________ concentration is used.
    • higher
    • lower
  65. as the concentration of iodine rises, name three other factors that also rise:
    • viscosity
    • osmolality
    • toxicity
  66. an IV would be a ___________ concentration, while a bolus would be a ___________ concentration.
    • lower
    • higher
  67. if you increase the number of iodine atoms in the molecule and keep the same number of molecules, the concentration:
    is increased
  68. if you increase the number of iodine atoms in the molecule but decrease the number of molecules, the concentration:
    stays the same
  69. the higher the numerical value of the ratio, the  ________ the osmolality for a given iodine
  70. 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
  71. both nonionic and ionic contrasts contain:
  72. 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)
  73. is a high iodine concentration more or less viscous?
  74. how is viscosity determined?
    • molecular size
    • molecular concentration
    • frictions of molecules in the solution
  75. name three things affected by viscosity:
    • flow rate
    • injection time
    • needle size
  76. what helps to reduce viscosity?
    warming the contrast to body temperature
  77. name two common aqueous iodine compounds:
    • diatrizoate meglumine
    • diatizoate sodium
  78. 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
  79. name two common high osmolar contrast agents (HOCAs):
    • renografin 60
    • hypaque 76
  80. high osmolar contrast agents (HOCAs) contain:
    sodium and meglumine salts
  81. name one of the first agents used in myelography and what it was replaced with:
    • metrizamide (amipaque)
    • replaced with hexabrix (meglumine ioxaglate)
  82. name some low osmolality contrast agents (LOCAs):
    • iopamidol (isovue, niopam)
    • iohexol (omnipaque)
    • ioversol (optiray)
  83. is a severe allergic reaction, may end in cardiac arrest or respiratory arrest, and less often seizures:
    anaphylactic shock
  84. 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
  85. _______ osmolality agents are routinely used and _________ are used for high risk patients.
    • low
    • isoosmolar
  86. total volume is dependent on:
    • concentration
    • type (ionic or nonionic)
    • weight and age of pt
    • anatomical structure
    • speed of injection
  87. žminimum amount of iodine needs to be given in order to have a satisfactory contrast enhancemnt of vascular stuctures and various tissues:
  88. factors affecting flow:
    • concentration
    • viscosity
    • temperature
    • catheter/needle diameter and length
  89. 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:
  90. the study of the preparation properties, uses, and the actions of drugs:
  91. the ________________ is sensitive to increased ions in the blood.
    central nervous system
  92. normal responses to ionic media:
    • sensation of warmth
    • light-headedness
    • nausea
    • vomiting
  93. allergic or anaphylactoid responses are caused by:
    • a release of histamine
    • (suggested that this is a CNS response)
  94. the result of interactions between the contrast medium and the blood, causing the suppression of certain enzymes:
    molecular toxicity
  95. the study of how drugs enter the body, are absorbed, reach their site of action, are metabolized, and exit the body:
  96. 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
  97. a chemical change that results in solid particles:
    • precipitation
    • (can cause a thrombus/stationary clot or embolus/moving blood clot)
  98. 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)
  99. be familiar with pre-contrast history items:
    • žhistory 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
    • žhistory of allergy
    • history of asthma
    • previous allergic reaction to contrast medium
    • note current medications
  100. give normal BUN and creatinine levels:
    • BUN: 8-25 mg/dl
    • creatinine: 0.6-1.5 mg/dl
  101. an increase in the diameter of blood vessels, which increases blood flow and lowers blood pressure:
  102. dangers of overdose:
    • repeat injection during arteriography
    • multiple exams scheduled in various depts.
    • change of doctor
  103. what type of patient is three times more likely to have an anaphylactoid reaction?
    asthma patient
  104. 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
  105. minute amount of contrast injected intravenously, followed by a pause during which the patient is observed carefully:
    test injection
  106. reactions have occurred with as little as _______ of contrast.
  107. signs of allergic reaction:
    • žrestlessness 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
  108. when a contrast is administered, how long must the patient be observed for signs of an allergic response?
    fifteen minutes
  109. 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)
  110. the medical abbreviation for four times a day:
  111. the medical abbreviation for twice a day: