Lecture 5 - Ultrasound Continued Flashcards

1
Q

List coupling agents

A
Gel

Petroleum based creams

Water based lotions

Immersion in Water –¼ inch to ½ inch from treatment area

Temperature of Coupling Agent

Phonophoresis
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2
Q

What is phonophoresis?

A

Processes by which we administer topical medication directly to the lesion site
- sometimes people cant take pills orally due to contraindication, same for injection so this is an alternative

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3
Q

Why do you think phonophoresis gets medication to the area faster?

A

-the whole idea is to bypass the bodies digestive process

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4
Q

How do you think phonophoresis works?

A

Driving medication directly through the tissue

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5
Q

What is one thing that limits phonophoresis effectiveness?

A
  • limited by the frequency of the sound head your using with regard to depth of penetration
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6
Q

What do you feel during each application to the quadriceps?

A

Continuous - Gentle warming
In general don’t feel a whole lot other then gentle heating
The patient will likely feel nothing and you will need to be able to explain why

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7
Q

What is Half –Value, Half Layer Rate

A

Frequency dependent

Always want to target 50% with regard to depth of lesion

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8
Q

why would you not want to target a lesion deeper then half value layer?

A
  • Not very effective - when you calculate chosen intensity calculate it based upon depth you can reach with a particular frequency
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9
Q

the higher the frequency the less ____ of penetration

A

depth

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10
Q

What is the penetration depth according to Starkey for 1MHz and 3MHz

A

1.5cm to 2cm with a 3Mhz with a 1MHz head 5cm - that is the max or half value distance as referenced in starkey

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11
Q

What does ERA stand for?

A

Effective radiating area (The amount of head that actually emulates the sound wave

Recognize ERA and actual size of the head are not the same

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12
Q

Why is ERA important?

A

Dictates how large of a lesion you can treat - which is 2x the size of the ERA

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13
Q

What is BNR?

A

Mass produced crystals will always have microimperfections and these imperfections will cause random peaks in the sound waves

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14
Q

What ratio of BNR is the limit?

A

8:1

elsa personally wouldnt use it beyond a ratio of 6:1

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15
Q

What does a BNR of 8:1 mean?

A

8:1 means 8 times the normal intensity

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16
Q

EXAM Q: What is Elsa and Starkey’s limit for BNR?

A

6:1

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17
Q

Ultrasound is used as one part of the rehabilitation process before exercising because….

A
  1. Thermal effects: increase tissue temperature
    - Allows tissue to stretch easier, gaining increase in rang of motion priming well for exercise
  2. Mechanical effects: even non-thermal effects break up waste products increasing cell diffusion and easily dissipated with subsequent exercise
    - The waste products is causing some of the limitation in ROM
    - Increased ROM will prime the patient for exercise
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18
Q

What must you know prior to ultrasound application?

A

Physiological effects

Therapeutic effects

Needs of the injured tissue

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19
Q

Why must you know the needs of the injured tissue prior to ultrasound application?

A

Heat in general and ultrasound respond to different type of tissues in different ways so knowing the type of tissue that is injured will help you get to where you want to go

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20
Q

What must you find out to determine dosage for ultrasound?

A
  1. Establish stage of healing
  2. Depth of the lesion
  3. Damage to tissue
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21
Q

The goals of the treatment and the ____ of the ultrasound must align

A

Dosage

- first and foremost determine aims of treatment

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22
Q

Increased frequency = ____ wavelength

A

Decreased

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23
Q

Increased frequency = ____ in height of waves

A

Decreased

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24
Q

Increased frequency = ____ tissue depth of penetration

A

Decreased

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25
Q

Increased frequency means the beam is more ____

A

Collimating (Parallel in nature)

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26
Q

Increase frequency = _____ absorption

A

Increase

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27
Q

Most important point is thermal and mechanical effects occur with _____ and no thermal effects, mechanical only with _____

A

Continuous

Pulsed

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28
Q

Describe continuous ultrasound

A

Continuous waves
Thermal effects

  • Pressure changes
  • Amplitude
  • Micromassage
  • Acoustic streaming
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29
Q

Describe pulsed ultrasound

A

Interrupted waves (bursts)

1:5 = 1/5 on and 4/5 off

% = 20% duty cycle

Non-thermal effects only

  • Pressure changes
  • Amplitude
  • Micromassage
  • Acoustic streaming
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30
Q

How much heat will 20% duty cycle generate?

A

None

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31
Q

How much heat will 50% duty cycle generate

A

A little

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32
Q

T/F increased duty cycle means more heat Ex. 80% produces more heat then 30%

A

True

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33
Q

When would you use pulsed ultrasound?

A

If you still have inflammation, if heating the area causes pain, if all you want to do is generate mechanical effects - for examples in a post-op fracture… you can use to break up scar tissue

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34
Q

Why would you not want to ultrasound a 7 day old fracture?

A

You would not want to disrupt a fracture in the early stage of healing. Once the fracture is stable.

  • new research that pulse ultrasound speeds up rate of healing
  • you have to look at parameters of the modality. dosages in and around the 0.01 - 0.03 w/cm squared were used in study. our machines at sheridan only go as low as 0.1 w/cm squared.
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35
Q

What should you ensure before using ultrasound on a fracture?

A

you want to make sure there is no risk of shock and that the fracture is stable - so it could be used relatively quickly (such as day 3)

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36
Q

What is attenuation with regard to ultrasound?

A
Attenuation: decrease in the US energy as a result of:
Reflection
Refraction
Absorption
Transmission
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37
Q

As wave is transmitted through the various tissues, there will be a _______ (or an attenuation) in energy intensity.

A

decrease

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38
Q

Attenuation occurs due to absorption or dispersion and scattering of the sound waves as a result of _____ or _____

A

reflection or refraction

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39
Q

Attenuation results in reduction of one-half its previous intensity in a certain distance (called ______)

A

“half-value distance” or HVD

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40
Q

Capability of the energy to penetrate to deeper tissues is determined by the _____ of the ultrasound as well as the _______ of the tissue through which it is traveling

A

Frequency.

Characteristics

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41
Q

Attenuation is ____ and ____ dependent

A

Frequency and tissue dependent

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42
Q

Absorption takes place at a _____ level

A

molecular

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43
Q

The greater the collagen content the greater the ______

A

absorption

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44
Q

Inverse relationship between absorption and ______

A

penetration

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45
Q

There is an increase in absorption with an increase in _______ –less energy is transmitted to the deeper tissue

A

frequency

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46
Q

fat does not absorb as much as we work our way ______

A

deeper

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47
Q

______ in nerve tissue will absorb a fair amount of energy - so need to be cautious

A

proteins

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48
Q

You will get better absorption with a (higher/lower)______ frequency - so better with _mhz rather then _mhz

A

higher. so better with a 3mhz rather then 1mhz

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49
Q

Ultrasound: List 4 properties that have the greatest amount of absorption

A

Ligaments
Cell membranes
Joint capsules
Highly collagenous tendons

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50
Q

every substance every bit of tissue has within itself acoustic impedence - it is this impedence that is going to change the ultrasound and reduce the _____ it carries through

A

energy

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51
Q

everytime you go through a different ____ you will get some sort of attenuation

A

interface

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52
Q

Amount reflected and amount transmitted is determined by the ________ of the two materials on either side of the interface

A

acoustic impedances

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53
Q

Describe reflection of energy

A

Some of the wave power is reflected back into the original medium

54
Q

Reflection is dependent on the difference in acoustic impedance between the tissues on either side of the interface. If the tissue is of the same make-up ____ reflection will occur

A

less

55
Q

____ in tissue will cause waves to be reflected back to the crystal

A

Air.

When arthroscopic surgery is conducted they blow a lot of air into the joint so need to be aware of this.

56
Q

Reflection –Important Interfaces

A
Bone-periosteuminterface
Tissue-air interface
Transducer head to air interface
Bone-soft tissue interface
Connective tissue interface
57
Q

When ultra ultrasounding tissue up against bone, we know that bone will absorb the ultrasound quite readily but also because of its density you will get a degree of _____

A

Reflection

58
Q

If you are ultrasounding a ligament next to a bone what do you think is happening to the bone absorbing the high energy and heat?

A

The bone heats up

59
Q

Muscles require high intensity ultrasound but if they are right up against bone you are heating up the bone and this will reuslt in ____

A

bone pain

60
Q

Reflection: Bone Periosteal interface

__% reflected, ___% absorbed

A

30% reflected, 70% absorbed

61
Q

Reflection: Bone –Periosteal Interface

Load to the periosteum is equal to the ____power plus the reflected power

A

incident

62
Q

Reflection: Bone –Periosteal Interface

Shear wave is generated at the boundary resulting in heat which is absorbed by the periosteum resulting in ______ ___

A

periosteal overheating

63
Q

____% reflection occurs at the tissue air interface

A

99.9%

64
Q

Tissue air interface creates localized high intensities and ____ waves

A

shear

65
Q

Tissue air interface is also occurring if you don’t make good contact with the ______

A

Sound head

66
Q

What is refraction?

A

deviation of the sound wave
Enters and leaves at different angles
Comes in at right angles = travels straight
Comes in on an angle = refracts

67
Q

Ultrasound wave transmission determined by:

A

acoustic impedance of the tissue

68
Q

High impedance = ____ in transmission of US

A

Increase

69
Q
Solids = \_\_\_\_ impedance

Water = \_\_\_\_ impedance

Air = \_\_\_\_ impedance
A

Solids = high impedance

Water = medium impedance

Air = low impedance

70
Q

How can the therapist avoid standing waves?

A

Keep the sound head moving

71
Q

How do standing waves occur?

A

Occurs when ultrasound traveling through tissues of various impedance
When reflected wave meets incoming incident wave

72
Q

Standing waves _____ intensity of the energy creating areas of high and low pressure (hot spots)

A

increase

73
Q

Preventing Standing Waves: Movement of the transducer is ____ dependent

A

BNR

74
Q

Preventing Standing Waves: Moving the transducer too ____ decreases the total amount of energy absorbed per unit area.

A

rapidly

75
Q

Preventing Standing Waves: Should only ever treat an area no bigger than ___ the size of the ______ (ERA)

A

2x

Transducer head

76
Q

Preventing Standing Waves: Slow movement = more control = even ____ throughout area

A

distribution

77
Q

Preventing Standing Waves: Fast moving transducer will not allow adequate _____ and sufficient heating will not occur (Prentice)

A

absorption

78
Q

Preventing Standing Waves: Rate of transducer movement is slow: maximum of ___ cm/sec. If the transducer is raced over the skin, ultrasound effects will be reduced. (Behrens and Michlovitz)

A

3-4 cm/sec

79
Q

List the non thermal effects of ultrasound

A

Acoustic Streaming (Microstreaming)

Cavitation

80
Q

ultrasound modality of choice over hot pack because of the ______

A

Mechanical effects

81
Q

microstreaming is a good thing cavitation can be ____

A

good and bad

82
Q

_____ cavitation = good

destructive cavtitation is unstable and bad

A

stable

83
Q

What is acoustic streaming

A

The unidirectional movement of fluids along the boundaries of cell membranes resulting from the mechanical pressure wave in an ultrasonic field

84
Q

In biological tissue this acoustic streaming is very small and is therefore referred to as _______

A

microstreaming

85
Q

Circular flow of bubble with acoustic streaming cause a change in cell _____ structure and function

A

cell membrane

86
Q

List 3 things micro streaming increases.
What does it promote?
What does it reduce?

A

Increases cell diffusion rate

Increased fluid interchange

Increases sound absorption

As a result you get the promotion of healing and some reduction of pain

87
Q

the bublles forming in our in lab experiment was an example of _____

A

cavitation

88
Q

Bubbles that form with cavitation will expand and ____ -

A

Contract

89
Q

What will the bubble formed through cavitation stimulate and facilitate?

A

it will stimulate the cells

facilitates healing process through transfer through the cell

90
Q

What is cavitation?

A

Formation of gas bubbles that expand and compress due to ultrasonically induced pressure changes in tissue fluids

91
Q

Describe stable cavitation:

A

Bubbles expand and contract in response to regularly repeated pressure changes over many acoustic cycles without growing to critical size

92
Q

Cavitation results in an increased flow in the fluid around these vibrating bubbles resulting in _____

A

microstreaming

93
Q

bubbles can implode due to increased intensity of the wave - the higher the intensity the more chances of _____ cavitation occuring

A

unstable

94
Q

For cavitation to occur when do you think the intensities would have to be higher? in a pulsed environment or continuous environment -

A

Pulsed

95
Q

unstable cavitation will occur more often in ____ intensities - whenever possible you should avoid _____ ultrasound due to these increased intensities

A

higher

pulsed ultrasound

96
Q

Describe unstable cavitation

A

Violent large excursions in bubble volume before implosion and collapse occurs after only a few cycles.

Creates increased pressure and high temperatures which cause local tissue damage

97
Q

How can you prevent unstable cavitation?

A

Lowest intensity possible

Avoid standing waves

Revert to higher frequency sound head thus reducing intensity

Using a low rate continuous setting allows you to keep the intensity low

98
Q

What are non-thermal biophysical effects of ultrasound?

A

Facilitation of tissue repair

Increase in cell permeability –an increase in the cells permeability allowing an influx of calcium

Stimulate the release of histamine

Increase in the degranulation of mast cells

Increase in the phagocytic activity

Increase in the number of fibroblasts causing an increase in protein synthesis which directly impacts tissue healing

Swelling reduction through the increase of blood flow

Bone Repair –only after a certain stage

99
Q

To achieve a therapeutic effect from ultrasound, the tissue temperature has to be maintained at
___ to ____ degrees for at least _ minutes.

A

40 to 45 degreesfor at least 5 minutes.

100
Q

List thermal effects of ultrasound

A
Increase metabolic rate

increase circulation

decrease pain

increase enzyme activity

increase extensibility of tissue

increase viscoelastic properties
Decrease joint adhesions, thus created an increase in joint range

Increase tissue healing

Increase collagen extensibility

Muscle spasm reduced
101
Q

EXAM Q: Where are ultra sounded greatest effects noted?

A

Wound Healing –greatest effects noted as it related to tendon, ligament, cartilage

102
Q

What does ultrasound do in the Inflammatory phase

A

Stimulates release of histamine from mast cells

103
Q

What does ultrasound do in the Proliferation phase

A

Reduction in the size and production of scar tissue

104
Q

What does ultrasound do in the remodeling phase

A

Change in collagen fibrepatterns giving rise to greater tissue elasticity

105
Q

EFFECTS OF ULTRASOUND ON VARIOUS TISSUE TYPES: Adipose Tissue

A

–very little energy absorbed

106
Q

EFFECTS OF ULTRASOUND ON VARIOUS TISSUE TYPES: Nervous Tissue

A

–similar to that found with other heat generating modalities
-effect on nervous tissues is same as other modalities with one exception - because of content of nerve you never want to ultrsound directly overtop a nerve

107
Q

EFFECTS OF ULTRASOUND ON VARIOUS TISSUE TYPES: Autonomic nervous system

A

Autonomic Nervous System –caution with patients who suffer from diabetes

108
Q

With regard to circulation what do you never want to ultrasound over?

A

A major blood vessel

109
Q

Contraindications for ultrasound

A

1) Specialized tissue
2) Cancer, Radiation
3) Infection
4) Viscera, Pregnancy
5) Cardiac Pacemaker
6) Thrombosis
7) Arteriosclerosis
8) Carotid Sinus, Stellate Ganglion
9) Laminectomy

110
Q

Important contraindications for ultrasound

A

1) Specialized tissue
2) Cancer, Radiation
4) Pregnancy
6) thrombosis - could dislodge a clot
9) laminectomy - Post-op proceedure where the lamina of a segment has been removed

Why is this a problem?
Spinal cord is exposed

111
Q

Ultrasound treatment precautions

A
Effused Joint

Bursitis

Epiphyseal plate

Arthritic Joints

Implants

Burns

Major Blood Vessels and Nerves

Therapist precautions
112
Q

Can you can use ultrasound on a bursa -

A

Yes

113
Q

How can you use ultrasound on a Bursa so it doesnt expand?

A

Pulsed

inflammation of the bursa will like pulsed ultrasound

114
Q

Prior to application of ultrasound what should you do?

A
Prepare US unit

Prepare patient

Tell them you desired outcomes

Contraindications

Get permission

Position patient comfortably and to allow for one minute stretch
115
Q

What is the dosage using the charting system based upon?

A
Based on aims of treatment

Stage of healing

Desired outcomes

Frequency (depth of lesion)

Tissue type

Interfaces

Coupling Agent
116
Q

Ultrasound protocol:

A
1.Aim of Treatment
–thermal or non-thermal
2.Determine depth of lesion
–Frequency
3.Position the patient
4.Explain treatment and get permission to apply
5.Go thru contraindications
117
Q

Ultrasound dosage must account for:

A

Tissue type-Organized collagen absorbs more ultrasound than muscle

Boney reflection

Refraction at interfaces

Coupling –gel, water

Depth of lesion –different frequencies

118
Q

If treat in water then ____ the intensity and make the water temperature appropriate

A

increase

119
Q

Increased collagen requires ___ intensity

A

less

120
Q

Tendon absorbs __ times more ultrasound than muscle

A

3 times

121
Q

Suggested ultrasound dosage for muscle

A

superficial -3.0MHz
.8 -1.0 w/cm2

deep -1.0 MHz
.8 –1.5 w/cm2

for 5 minutes

122
Q

Suggested ultrasound dosage for tendon, ligament, capsule or adhesions

A

superficial -3.0 MHz
.3 -.5 w/cm2

deep -1.0 MHz
.4 -.8 w/cm2

for 5 minutes

123
Q

Ultrasound application precautions

A

Never turn on the ultrasound unit until the sound head has coupling media and head is against the skin surface

Do not heat or chill the treatment area with a hot pack or cold pack first

124
Q

Ultrasound treatment schedule

A

Inflamed -treat every other day
-pulsed 20% duty cycle

Demolition, healing-treat daily
-low intensity continuous

ChronicCondition -treat daily
-mild -medium and high intensity continuous

125
Q

Reevaluate the dosage and use every ____ treatments

A

3

126
Q

___ treatments maximum to determine if condition is improving and the use is appropriate

A

12

127
Q

Describe the stretch window. How long does it last?

A

Window of tissue viscoelasticity and heat (Draper)

Last minute of treatment and for 5 more minutes

128
Q

Will thermal effects last longer with a 1Mhz or 3Mhz?

Will you get to therapeutic range faster with a 1Mhz or 3Mhz?

A

Thermal effects last long (decay slower) with a 1 MHz treatment vs. a 3MHz treatment although you will get to therapeutic range faster with a 3MHz treatment

129
Q

Would you ultrasound a hematoma?

If so when?

A

You can on a continuous setting with a low intensity. AFTER 8-10 days.

Should be checking the site before U/S to see if there is a buildup and how deep it is.

130
Q

What happens if you ultrasound a deep hematoma before it is safe to do so?

A

Could produce Myositis ossificans in the muscle belly.