Brainscape's Knowledge GenomeTM

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


See full index

Sonography Principles 2 > Elastography > Flashcards

Elastography Flashcards

1
Q

What does elastography measure?

A

Stiffness of the liver

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

What is used to measure the stiffness of a material?
(hint: the units)

A

Youngs Modulus in kPa

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

What unit is Young’s modulus measured in?

A

kPa

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

What is true of materials with a SMALL young’s modulus?

A

Softer material and a larger strain as it can compress more easily

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

What is true of materials with a LARGE young’s modulus?

A

Stiffer material and a small strain as it cannot compress very easily

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

What type of ultrasound technology is used for shear wave imaging?

A

Elastography

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

In shear wave imaging, how is the stiffness of liver quantified?

A

It is measured in kPa and a HIGHER score indicates a greater stiffness

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

What is the range in kPa for soft tissue?

A

1-300 kPa

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

What is the value in kPa for fat vs. fibrotic liver?

A

Fat = 1

Fibrotic liver = 300

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

What is the formula for Young’s modulus?

A

Force/strain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the ratio of the applied stress to the resulting strain a result of?

A

A stress that either compresses or stretches tissue - measured with Young’s modulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Elastography provides an imaging means of?

A

Palpation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What method in elastography involves initiating a MANUAL force to the tissue?

A

STATIC

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

In using what method can Young’s modulus not be quantified and only uses qualitative information?

A

Static method

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

Applications of static elastography?

A
  1. Cancer detection of small parts (breast, thyroid, prostate)
  2. Myocardium viability
  3. Monitoring of therapies that alter tissue composition such as ablation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Dynamic methods use what kind of force?

A

Short transient force or time-varying repetitive force

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

What force is INITIALLY produced in a dynamic method?

A

Compressional strain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is another term for compressional strain?

A

Transient or oscillatory

19
Q

Does compressional strain travel at a high or low propagation speed? What is the speed?

A

High: 1440-1640 m/s

20
Q

Through what kind of force is a compressional strain converted to shear waves?

A

Radiation force

21
Q

Do shear waves travel at a high or low propagation speed? What is the speed?

A

Low: 0.5-10 m/s

22
Q

In what direction do shear waves propagate in tissue during shear wave elastography?

A

Perpendicular to the direction of tissue compression

23
Q

How can shear displacements of propagating shear waves be tracked?

A

Ultrafast by using high frame rates to determine their propagation speed

24
Q

What does ARFI stand for?

A

Acoustic Radiation Force Impulse Imaging

25
Q

What is the function of ARFI?

A

Determining propagation speed of tissue to determine the stiffness

26
Q

How do we determine propagation speeds in shear wave imaging?

A

Using high frame rates

27
Q

What units is shear wave reported in?

A

m/s

28
Q

What kind of method is used to determine quantitative information?

A

Dynamic

29
Q

Where do we scan for shear wave?

A

Intercostally

30
Q

What segments of the liver are shear wave measurements taken from?

A

7 or 8

31
Q

Take elastography measurements using what kind of breath on a patient?

A

Suspended breath hold

32
Q

Where should the shear wave box be located?

A

1-2 cm below liver capsule

33
Q

T or F? We should always increase the gain in shear wave imaging

A

FALSE: Do not attempt to increase the gain as it will likely lead to an inaccurate measurement

34
Q

To have a good shear wave measurement, how much colour must be filled in?

A

> 50%

35
Q

F1 Normal to mild fibrosis staging in kPa?

A

5.48-8.29

36
Q

F2 mild to moderate fibrosis staging in kPa?

A

8.29-9.4

37
Q

F3 moderate to severe fibrosis staging in kPa?

A

9.4-11.9

38
Q

F4 Cirrhosis

A

> 11.9

39
Q

What position is the patient usually in during elastrography?

A

Supine or LLD with R arm above head

40
Q

What method uses both qualitative and quantitative assessment of liver stiffness?

A

Dynamic - no force applied

41
Q

T or F? Radiation force is most intense at the focal zone?

A

TRUE

42
Q

Radiation force is a result of a change in wave?

A

Momentum due to scattering at an obstacle

43
Q

What is measured to equal radiation force?

A

Rate of momentum change, averaged over the period of the wave

Sonography Principles 2 (14 decks)

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