Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

CT & MRI > CT Application 1 CM > Flashcards

CT Application 1 CM Flashcards

1
Q

Role of contrast media

A
  • improve sensitivity & specificity
  • differentiation
  • evaluate vascular structures
  • assess abdominopelvic region
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

high contrast CT exams usually require ____ to differentiate structures of different densities

A

no contrast media

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

low contrast CT exams usually require ____

A

contrast media to improve tissue contrast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what type of contrast are CO2 and Air

A

negative contrast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what type of contrast are water & volumen

A

neutral contrast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

how does the diff contrast appear as

A

positive contrast - white
neutral “ - grey
negative “ - black

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what type of contrast are barium & iodinated

A

positive contrast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

example of barium contrast

A

barium sulphate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

example of iodinated contrast

A

iodine based IV contrast gastrografin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

limits of using plain water

A
  1. transits rapidly & absorbed distally
  2. suboptimal distension which mimics / masks lesions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

pros of using plain water

A

AVA

  1. administered orally
  2. assess luminal pathology & bowel wall
  3. very good for upper GIT if scanned at appropriate timing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what does VoLumen contain

A
  • diluted barium sulfate suspension
  • sorbitol
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what effect does sorbitol have

A

laxative effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

how many bottles does a patient drink

A

2-3 bottles of VoLumen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how can barium contrast be administered

A

oral & rectal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is barium contrast commonly used in

A

esophagus, intestine, very intense intestinal contrast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

contra-indications of barium

A
  1. intestinal perforation
  2. intestinal obstruction
  3. swallowing difficulties
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

K-edge of iodine

A

33.2 keV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is a function indicator of x-ray energy

A

probability of photoelectric absorption since it corresponds to binding energy of iodine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

higher kVp leads to ___ compton effect & ___ photoelectric effect

A

higher; lower

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

properties of iodinated contrast

A
  • oligomerization
  • iodine concentration
  • osmolarity
  • viscosity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what are the 2 main groups and subgroups of water soluble iodinated contrast

A

ionic
- monomer + dimer

non-ionic
- monomer + dimer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

currently available contrast media are either __

A

monomer (1 benzene ring) + dimer (2 benzene ring)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

examples of ionic iodinated contrast media

A
  1. hypaque
  2. isopaque coronar
  3. hexabrix
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what is gastrografin

A

diatrizoate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what is hypaque AKA

A

diatrizoate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what is isopaque coronar AKA

A

metrizoate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what is hexabrix AKA

A

ioxaglate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

examples of non-ionic iodinated contrast

A
  1. ultravist
  2. visipaque
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what is ultravist AKA

A

iopromide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what is visipaque AKA

A

iodixanol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

although overdose is unlikely but possible, ___ needs to be defined

A

upper limits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what factors influence iodine concentration/dose

A

protocol, injection rate, delay imaging

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

how is iodine concentration standardized for pediatric patients

A

weight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

drink ___ of water to minimize iodine side effects

A

1L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what is osmolarity

A

measurement assessing number of particles dissolved in 1kg of water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Osmolality of iodinated contrast media is compared to the osmolality of ___

A

human plasma (300mOsm/kg H2O)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

iodinated contrast is either ___ or __ tonic

A

hyper-; iso-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what does osmolarity contribute to

A
  • non-allergic adverse reactions
  • injection pain
  • endothelial damage
  • RBC deformation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

what is the osmolarity of ionic CM

A

very high

41
Q

what is the osmolarity of non-ionic CM

A

moderate to high

42
Q

cP

A

centipoise

43
Q

what is viscosity of IV CM

A

measure of liquid resistance / friction to flow

44
Q

what does viscosity of IV CM influence

A
  • IV injectability
  • cannula gauge
  • contrast induced kidney injury risk
45
Q

high viscosity leads to ___ infusion times

A

longer

46
Q

how much iodine containing CM is removed 24hr after IV administration

A

90% mostly eliminated by kidneys

47
Q

in the event of renal failure / insufficiency, how can CM be extracted

A

dialysis

48
Q

iodine containing CM can/cannot cross cell membranes or Blood brain barrier

A

cannot

49
Q

CM firstly transits through the vessel system (“Vascular compartment”) and secondly enters the space between vessels and cells (“interstitial compartment”) by ____

A

free diffusion

50
Q

what are the 3 main groups of IV contrast enhancement

A
  1. patient
  2. CT scanning parameters
  3. contrast media
51
Q

what are the scan delays possible

A

fixed, test-bolus, bolus-tracking

52
Q

what are the injection patterns available

A

uniphase, biphase, exponentially decay

53
Q

iodine dose formula

A

(concentration x vol of contrast) / 1000

54
Q

why should the CM administered be greater in larger patients compared to smaller patients?

A

larger patients = larger blood volume = more diluted CM

55
Q

what are the diff cannula available

A

18G, 20G, 22G, 24G

56
Q

what is the flow rate of 18G

A

4 - 6 ml/s

57
Q

what is the flow rate of 20G

A

3 - 4 ml/s

58
Q

what is the flow rate of 22G

A

2 - 3 ml/s

59
Q

what is the flow rate of 24G

A

1 - 1.5 ml/s

60
Q

which cannula for pediatrics

A

24G

61
Q

which cannula for difficult veins esp post chemotherapy

A

24G

62
Q

which cannula for arterial & venous phase of CT scan

A

22G

63
Q

which cannula for most phases

A

20G

64
Q

which cannula for fast CT contrast flowing studies

A

18G

65
Q

saline chaser allows for the reduction of ___

A

contrast volume & increases peak attenuation

66
Q

saline chaser reduces ___ artifacts from vein & right heart

A

streak

67
Q

adverse reactions of IV iodinated contrast

A
  1. CI-AKI
  2. adverse reaction post administration
  3. extravasation
  4. air embolism
68
Q

CI-AKI means?

A

contrast induced - acute kidney injury

69
Q

which patients are prone to CI-AKI

A

patients with compromised kidney function such as diabetes and chronic kidney disease

70
Q

what indicators suggest patient is at higher risk of AKI

A
  • eGFR (mL/min): 30 - 0
  • elevated serum creatinine (mg/dL): 2 - 4.5
  • Moderate reduced kidney function
71
Q

how to reduce chance of CI-AKI

A
  1. screen for patient risk
  2. administer periprocedural hydration
  3. lower osmolar iodinated contrast media
  4. stop metformin
72
Q

NSAIDs

A

Non-Steroidal Anti-Inflammatory Drugs

73
Q

how to minimize reactions

A
  • hydration
  • stop NSAIDs
  • use other modalities / non-contrast
74
Q

eGFR is calculated using ___

A

diet modification in renal disease formula

75
Q

what do you need for diet modification in renal disease formula

A
  • serum creatinine
  • age
  • gender
76
Q

serum creatinine is ___ indicator of kidney function

A

insensitive

77
Q

what is the best overall indicator of kidney function

A

GFR

78
Q

eGFR

A

estimated glomerular filtration rate

79
Q

if eGFR > 90, should you continue with IV iodinated CM

A

yes since excretion half time is 1-2 hrs

80
Q

if eGFR > 60, should you continue with IV iodinated CM

A
  • weight benefits & risks with radiologist
  • consider other modalities / non-contrast
  • recheck serum creatinine and eGFR 48 hrs after scan
81
Q

if eGFR < 30, should you continue with IV iodinated CM

A

if on dialysis, use non-contrast/other modalities

if not on dialysis, recheck serum creatinine and eGFR 48 hrs after scan

82
Q

____ are well established methods to prevent CI-AKI

A

volume expansion & hydration treatment

83
Q

IV saline hydration reduces risk of CI-AKI by ___

A

almost 50%

84
Q

lactic acidosis

A

when lactate production exceeds its metabolism in your body

85
Q

what is the main factor for metformin related lactic acidosis

A

diabetes

86
Q

how to minimize reactions involving metformin

A
  • discontinue 48 hrs after contrast
  • check creatine before resuming
87
Q

what causes 50% mortality for adverse reactions

A

metformin + chronic renal insufficiency + IV contrast = lactic acidosis

88
Q

when to resume metformin

A

eGFR > 30mL/min/1.73m^2

89
Q

protocol for eGFR < 30mL/min/1.,73m^2

A

stop metformin 48hrs before and after CM injection

90
Q

which pathway involves IgE allergic reaction

A

anaphylactic true allergy

91
Q

what are the IV contrast reaction pathways

A
  • anaphylactic true allergy
  • anaphylactoid “allergy-like”
92
Q

what do IV contrast reactions activate

A

mast cells

93
Q

strategies to avoid adverse reactions

A
  1. evaluate risk and benefit
  2. use other modalities / non-contrast
  3. diff CMs
  4. guidelines if contrast must be used
94
Q

what causes extravasation

A

failed IV injection leading to compartment syndrome

95
Q

what is compartment syndrome

A

increased pressure within confined space

96
Q

management strategies for extravasation

A

MISE

  1. elevate limbs
  2. ice pack
  3. monitoring
  4. surgery if severe
97
Q

clinical feature of air embolism

A
  1. dyspnoea
  2. cough
  3. chest pain
98
Q

treatment for air embolism

A
  • 100% oxygen
  • hyperbaric oxygen tank
  • patient in left lateral decubitus

CT & MRI (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions