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DPT 690 - PT Interventions II > Ultrasound > Flashcards

Ultrasound Flashcards

1
Q

Therapeutic ultrasound frequency between (?) and (?) megahertz (MHz)

Ultrasound

A

Therapeutic Ultrasound:

(-) Therapeutic ultrasound = frequency between 0.7 and 3.3 megahertz (MHz)

  • Megahertz = 1 million Hz
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2
Q

Attenuation:

  • What is it = ?
  • Occurs via = ?

Ultrasound

A

(a) Attenuation: Decreased signal intensity as ultrasound travels through tissues

  • Note: attenuation varies by tissue type

(b) Attenuation occurs via

  • absorption
  • reflection, and
  • refraction

(c) Air is poor conductor of ultrasound, therefore need conducting medium.

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3
Q

Effects of Ultrasound

What modalities:

  • Conduction = ?
  • Convection = ?
  • Conversion = ?
  • Radiation = ?

Ultrasound

A

Conduction =

  • Hot Packs / Cold Packs
  • Paraffin

Convection =

  • Whirlpools
  • Fluidotherapy

Conversion =

  • Diathermy

Radiation =

  • Infrared heat lamps
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4
Q

Conversion

Rate of tissue temperature increase depends on = ?

Ultrasound

A

Conversion:

(a) Not affected by the temperature of the thermal agent.

(b) Rate of heat transfer depends on the power of the energy source.

(c) Rate of tissue temperature increase depends on:

  • Size of the are being treated
  • Size of the applicator
  • Efficiency of transmission from the applicator to the patient
  • Type of tissue being treated

(d) DOES NOT require direct contact between the thermal agent and the body.

(e) DOES require an intervening material to be a good transmitter of that type of energy.

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5
Q

Thermal Effects of Ultrasound

Thermal effects can vary by parameters used:

  • 3 MHz = What depth ?
  • 1 MHz = What depth ?

Ultrasound

A

Thermal Effects of Ultrasound:

(a) Physiologic studies indicate thermal ultrasound can increase tissue temperature.

  • Best at heating tissues with high ultrasound absorption coefficients (collagen > water).
  • Ultrasound heats smaller, deeper areas better than superficial heat.

(b) Thermal effects can vary by parameters used

  • 3 MHz = 1-2 cm tissue depth
  • 1 MHz = 2-5 cm tissue depth

(c) Note:

  • 3 MHz is associated with increased overall tissue temperatures, therefore may need to use decreased intensity (W/cm2) at 3 MHz compared to 1 MHz.
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6
Q

Thermal Ultrasound Considerations = ?

Ultrasound

A

Thermal Ultrasound Considerations:

(a) Keep soundhead moving to avoid hot spots

  • Speed of sound head moving does not appear to affect temperature produced

(b) Patient’s report of warmth used to determine final ultrasound intensity (W/cm2).

  • Note: Frequency of 3 MHz associated with increased overall tissue temperatures, therefore may need to use decreased intensity (W/cm2) at 3 MHz compared to 1 MHz
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7
Q

Non-thermal Ultrasound Effects

Non-thermal effects from mechanical events, include = ?

Ultrasound

A

Non-thermal Ultrasound Effects:

(a) Non-thermal effects from mechanical events, include

  • Cavitation,
  • Microstreaming, and
  • Acoustic streaming

(b) Ultrasound with low average intensity increases cell membrane permeability and macrophage responsiveness.

(c) Obtain non-thermal effects by decreasing duty cycle (% time on)/

  • Heat generated during on time / dispersed during off time.
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8
Q

Research

Ultrasound for…

  • Knee OA = ?
  • CTS = ?
  • Chronic LBP = ?
  • Adhesive Capsulitis = ?

Ultrasound

A

Ultrasound:

  • Knee OA = Low Evidence
  • CTS = Poor Evidence
  • Chronic LBP = No Quality Evidence
  • Adhesive Capsulitis = Improvements in ROM, shoulder disability, and pain in both groups(experiment & control)
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9
Q

Ultrasound

Contraindications = ?

Ultrasound

A
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10
Q

Adverse effects of ultrasound include = ?

Ultrasound

A

Adverse Effects of Ultrasound:

  • Burns most common (hot spots)
  • Potential for cross-contamination.
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11
Q

Ultrasound Application Considerations = ?

Ultrasound

A

Ultrasound Application Considerations:

  • Thermal or non-thermal effects desired?
  • Treatment depth desired?
  • What is size of treatment area?
  • Treatment time?
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12
Q

Describing Ultrasound

  • Intensity = ?
  • Frequency = ?
  • Duty cycle = ?
  • Duration = ?

Ultrasound

A

Intensity:

  • Quantity of energy delivered per unit area (W/cm2)

Frequency:

  • Determines depth of ultrasound (MHz)

Duty cycle:

  • Described in terms of percentage on time (continuous or pulsed)

Duration:

  • Length of treatment
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13
Q

Ultrasound Application

Impairments = Soft tissue shorting & Pain

  • Effects of ultrasound = ?
  • Duty Cycle = ?
  • Depth of problem = 2-5 cm
  • Frequency = ?
  • Intensity = ?
  • Duration = ?

Ultrasound

A

Ultrasound Application:

Impairments = Soft tissue shorting & Pain

  • Effects of ultrasound = Thermal
  • Duty Cycle = 100%
  • Depth of problem = 2-5 cm
  • Frequency = 1 MHz
  • Intensity = 1.5-2.0 W/cm^2
  • Duration = 5-10 min/2 x ERA
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14
Q

Ultrasound Application

Impairments = Soft tissue shorting & Pain

  • Effects of ultrasound = ?
  • Duty Cycle = ?
  • Depth of problem = 1-2 cm
  • Frequency = ?
  • Intensity = ?
  • Duration = ?

Ultrasound

A

Ultrasound Application:

Impairments = Soft tissue shorting & Pain

  • Effects of ultrasound = Thermal
  • Duty Cycle = 100%
  • Depth of problem = 1-2 cm
  • Frequency = 3 MHz
  • Intensity = 0.5 W/cm^2
  • Duration = 5-10 min/2 x ERA
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15
Q

Ultrasound Application

Impairments = Delayed tissue healing & prolonged inflammation

  • Effects of ultrasound = ?
  • Duty Cycle = ?
  • Depth of problem = 1-2 cm
  • Frequency = ?
  • Intensity = ?
  • Duration = ?

Ultrasound

A

Ultrasound Application:

Impairments = Delayed tissue healing & prolonged inflammation

  • Effects of ultrasound = Non-thermal
  • Duty Cycle = 20%
  • Depth of problem = 1-2 cm
  • Frequency = 3 MHz
  • Intensity = 0.5-1.00 W/cm^2
  • Duration = 5-10 min/2 x ERA
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16
Q

Ultrasound Application

Impairments = Delayed tissue healing & prolonged inflammation

  • Effects of ultrasound = ?
  • Duty Cycle = ?
  • Depth of problem = 2-5 cm
  • Frequency = ?
  • Intensity = ?
  • Duration = ?

Ultrasound

A

Ultrasound Application:

Impairments = Delayed tissue healing & prolonged inflammation

  • Effects of ultrasound = Non-thermal
  • Duty Cycle = 20%
  • Depth of problem = 2-5 cm
  • Frequency = 1 MHz
  • Intensity = 0.5-1.00 W/cm^2
  • Duration = 5-10 min/2 x ERA
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17
Q

Duty Cycle

Duty Cycle

  • Is either (?) or (?)
  • Determind by = ?

Ultrasound

A

Duty Cycle:

(a) Either continuous (100%) or pulsed (20%)

  • Select according to treatment goal

(b) Thermal Effects = Continuous (100%)

  • Intensity remains constant throughout treatments
  • Increase tissue temperature

(c) Nonthermal effects of tissue healing = Pulsed (20%)

  • Produces intensity 20% of the time (on + off time)
  • Increase intracellular calcium levels
  • Increase skin and cell membrane permeability
18
Q

Duty Cycle

  • Continuous (100%), increases = ?
  • Pulsed (20%), increases = ?

Ultrasound

A

(a) Continuous (100%) – Thermal Effects

  • Increase tissue temperature

(b) Pulsed (20%) - Nonthermal effects of tissue healing

  • Increase intracellular calcium levels
  • Increase skin and cell membrane permeability
19
Q

Frequency

  • Determines = ?
  • 1-2 cm deep = _ ? _ MHz
  • 3-5 cm deep = _ ? _ MHz

Ultrasound

A

Frequency:

(a) Determines depth of the ultrasound

  • Higher frequency is more rapidly absorbed

(b) Attenuation

  • Higher water content areas = low rate of absorption
  • More dense tissues = higher rate of absorption

(c) Select based on depth of tissue

  • 1-2cm deep = 3MHz = Shallow tissue
  • 3-5cm = 1 MHz = Deeper tissue
20
Q

Intensity

Lower intensity at = ?

Ultrasound

A

Intensity:

(a) Quantity of energy delivered per unit area

  • Not uniform power
  • Some areas more intense than others

(b) Lower intensity at higher frequency

  • Great temp increase from energy absorbed in smaller, more superficial volume.
  • Considered for areas with superficial bone

(c) Increase intensity based on pt considerations

  • Asking patients if they feel it.
  • Feel nothing? Increase it.
  • Too hot? Decrease it
21
Q

Intensity

True or False:

A lower-intensity at higher frequency results in energy being absorbed in smaller, more superficial volume and results in greater temp increases.

Ultrasound

A

Intensity:

True -

  • A lower-intensity at higher frequency results in energy being absorbed in smaller, more superficial volume and results in greater temp increases.

Thermal -

(a) Increase tissue temperature

  • Increase warmth within in 2-3 minutes
  • Should not feel any increasing discomfort
  • 1 MHz = 1.5-2.0 W/cm2
  • 3 MHz = 0.5 W/cm2

Non-Thermal -

(a) 0.5 to 1.0 W/cm2

  • As low as 0.15 W/cm2 for bone healing

(b) Remember

  • No tissue warming, works at cellular level

Notes -

  • Lower-intensity at higher frequency – energy is absorbed in smaller, more superficial volume and results in greater temp increases.
  • Increase up/down depending on pt reports – nothing after 2-3 minutes, then increase; discomfort reported? = Then decrease it.
  • Superficial bone – low intensity may be sufficient for comfortable heating.

Read notes in PP

22
Q

Intensity

  • Area of the crystals that produce energy = ?
  • Ratio between spatial-peak intensity and spatial average intensity = ?

Ultrasound

A

Intensity:

(a) Effective Radiating Area (ERA) =

  • Area of the crystals that produce energy
  • Smaller than total size of the head
  • Concentrated near the center
  • Treat an area 2-4x the size of the sound head

Spatial-peak intensity

  • Intensity of the ultrasound beam at its highest point

Spatial-Average Intensity

  • Intensity on an ultrasound unit in W/cm2

(b) Beam Nonuniformity Ratio (BNR) =

  • Ratio between spatial-peak intensity and spatial average intensity.

Described on the machine

  • 2:1 to 8:1 average ranges
  • 5:1 and 6:1 are common

Lower BNR

  • More favorable as patients will experience less hot spots and discomfort.

Higher BNR

  • Move the transducer head faster to avoid undesireable effects “hot spots”.
23
Q

Intensity - Effective Radiating Area (ERA)

  • Spatial-peak intensity = ?
  • Spatial-Average Intensity = ?

Ultrasound

A

Intensity:

(a) Effective Radiating Area (ERA) =

Spatial-peak intensity

  • Intensity of the ultrasound beam at its highest point

Spatial-Average Intensity

  • Intensity on an ultrasound unit in W/cm2
24
Q

Intensity - Beam Nonuniformity Ratio (BNR)

  • Described on the machine as = ?
  • With a lower BNR, patients will experience less = ?
  • With a higher Higher BNR, it’s important that we (PT’s) = ?

Ultrasound

A

Intensity: - Beam Nonuniformity Ratio (BNR):

(a) Described on the machine =

  • 2:1 to 8:1 average ranges
  • 5:1 and 6:1 are common

(b) Lower BNR =

  • More favorable as patients will experience less hot spots and discomfort.

(c) Higher BNR =

  • Move the transducer head faster to avoid undesireable effects “hot spots”.
25
Duration depends on = **?** ## Footnote *Ultrasound*
**Duration**: (**a**) Duration depends on: * Treatment goal * Size of area to be treated * The ERA of the sound head  (**b**) Generally – 5-10 minutes for each treatment area 2x/ the ERA of sound head. * Treatment area = 20 cm^2 * Sound head = 10 cm^2 * Duration = 5-10 min. (**c**) Increase duration if... * Lower intensity (consider bone healing at 0.15 W/cm2) * Larger treatment areas * Higher tissue temperature desired  (**d**) Decrease duration if... * Higher intensity * Smaller areas  * Lower tissue temp
26
# Duration * Increase duration if = **?** * Decrease duration if = **?** ## Footnote *Ultrasound*
**Duration**: (**c**) Increase duration if... * Lower intensity (consider bone healing at 0.15 W/cm2) * Larger treatment areas * Higher tissue temperature desired  (**d**) Decrease duration if... * Higher intensity * Smaller areas  * Lower tissue temp
27
# Area to be treated * Depends on = **?** * DO NOT = **?** ## Footnote *Ultrasound*
**Area to be treated**: (**a**) Depends on ERA of sound head  (**b**) Do not...  * exceed 4x the area of the sound head  * Treat 1.5 x less the size of the sound head  (**c**) Move soundhead overlapping by half (**d**) Use coupling agent
28
# Coupling Agents * Coupling Agents = **?** * Direct Coupling Agents = **?** * Indirect Coupling Agent = **?** * Water immesion = **?** ## Footnote *Ultrasound*
**Coupling Agents**: (1) **Coupling Agents** = * Decrease attenuation and acoustical impedance  * Eliminates air between transducer and target area (2) **Direct Coupling Agents** = * Gel, Lotion  * Apply prior to turning on  * Keep transducer parallel with surface of skin  * If ***NOT***  maintained, energy will be reflected and can damage transducer and patient  (3) **Indirect Coupling Agent** = * For small area, irregularly shaped, or unable to tolerate direct pressure. * Water immersion * Gel/water filled bladders, gel pads * Cushion Contact (4) **Water immesion** = * Rubber or plastic, not metal, container  * Move parallel to skin, 0.5-3.0cm away  * Wipe away air bubbles * Increase intensity as much as 50% 
29
# Move the sound head Speed approximately = **?** ## Footnote *Ultrasound*
**Move the Sound Head**: (**a**) Speed approximately = **4cm/sec** * Quick enough to avoid stopping * Slow enough to maintain contact ***Stopped or too slow?*** * Increased intensity in that one area  * Result in burning  * Reduced efficacy of treatment  ***Too quickly?*** * Ineffective treatment
30
# Treatment Amount * Thermal Ultrasound = **?** * Nonthermal Ultrasound = **?** | - When in the healing process - How many times / week ## Footnote *Ultrasound*
**Treatment Amount**: (a) ***Thermal Ultrasound*** * Later in healing process  * Commonly 2-3x/week  (b) ***Nonthermal ultrasound***  * Earlier in process * Once a day - Should note positive response in first 3 sessions  (c) ***Failure to receive response*** ? * Change parameters * Choose another intervention
31
Stationary Method = **?**
**Stationary Method**: **Not recommended** * Uneven heating * Undesirable effects * Pain or tissue damage **-** VERY small treatment area **-** Pulsed ultrasound with low intensity 
32
Potential Conditions for Ultrasound = **?** ## Footnote *Ultrasound*
**Potential Conditions for Ultrasound**: * Soft tissue shortening * Pain control * Dermal ulcers * Surgical skin incisions * Tendon and ligament injuries * Resorption of calcium deposits/calcific tendonitis * Bone fractures
33
# Soft Tissue Shortening - Based on this, what are we thinking = **?** ## Footnote *Ultrasound*
**Soft Tissue Shortening**: **-** Want increase temperature to increase tissue extensibility **-** Based on this, what are we thinking? * ***Thermal***, so continuous duty cycle * ***Frequency*** depends on depth of tissue (1 MHz up to 5 cm, 3 MHz for 1-2 cm depth) * ***Intensity*** likely 1.5-2.0 W/cm2 (0.5-1.0 W/cm2 if using 3 MHz)
34
# Pain Control Based on this, what are we thinking = **?** ## Footnote *Ultrasound*
**Pain Control**: **-** Want increase tissue temperature for relaxation, tissue extensibility. **-** Based on this, what are we thinking? * ***Thermal***, so continuous duty cycle. * ***Frequency*** depends on depth of tissue (1 MHz up to 5 cm, 3 MHz for 1-2 cm depth). * ***Intensity*** likely 1.5-2.0 W/cm2 (0.5-1.0 W/cm2 if using 3 MHz).
35
# Dermal Ulcers Based on this, what are we thinking = **?** ## Footnote *Ultrasound*
**Dermal Ulcers**: **-** Robust and conclusive evidence lacking – more likely to use electrical stimulation as modality of choice for wound healing. **-** Want mechanical effects **-** Based on this, what are we thinking? * ***Non-thermal***, so pulsed duty cycle (20%) * ***Frequency*** at 3 MHz as ulcer superficial * ***Intensity*** 0.5-1.0 W/cm2
36
# Surgical Skin Incisions Based on this, what are we thinking = **?** ## Footnote *Ultrasound*
**Surgical Skin Incisions**: **-** Some evidence for effectiveness **-** Want mechanical effects **-** Based on this, what are we thinking? * ***Nonthermal***, so pulsed duty cycle (20%) * ***Frequency*** depends on depth of tissue (1 MHz up to 5 cm, 3 MHz for 1-2 cm depth) * ***Intensity*** 0.5-1.0 W/cm2
37
# Tendon and Ligament Injuries Based on this, what are we thinking = **?** ## Footnote *Ultrasound*
**Tendon and Ligament Injuries**: **-** Consider acuity of injury in determining treatment parameters. * ***Acute***: likely want non-thermal for healing and mechanical effects. * ***Chronic***: likely want thermal for increasing temperature and extensibility.
38
# Bone Fractures Based on this, what are we thinking = **?** ## Footnote *Ultrasound*
**Bone Fractures**: * Low-dose ultrasound * Unlikely to see in typical regular practice
39
* Phonophoresis = **?** * Settings = **?** ## Footnote *Ultrasound*
**Phonophoresis**: Application of topical (transdermal) medication via ultrasound * Anti-inflammatory & analgesics  (**a**) Enhances distribution through the skin  * High concentration of medication delivery  (**b**) Non-thermal settings: * 20% duty cycle, 3 MHz, 0.5-0.75 W/cm2 * Effective conductors of acoustic energy  ## Footnote *Limited evidence*
40
# Documentation What needs to be included = **?** ## Footnote *Ultrasound*
**Documentation**: * Area of the body treated * US Frequency * US intensity * US duty cycle * Treatment duration * Pt response 
41
Describe the application process = **?** ## Footnote *Ultrasound*
**Application**: (**1**) Properly explain your treatment and reason for modality. * Clear contraindications (**2**) Comfortably position patient for effective treatment  * Proper draping/towels as needed (**3**) Inspect skin before and after treatment * Remove jewelry or any metals in area  * CLEAN THE SKIN (**4**) Set up machine to appropriate settings * Do not start yet (**5**) Place gel on skin and/or transducer * Move gel around (**6.a**) Start moving ultrasound head on skin  * Then start treatment * Check in on intensity after 2-3 minutes (**6.b**) Need to pause? * While still moving sound head, hit pause – you can now remove sound head * Once you are ready to start, make sure you are moving sound head then start (**7**) Finish * Hit stop while still moving sound head * Clear to remove sound head * Wipe off gel, check the skin, reassess function
42
Ultrasound - ***Summary*** ## Footnote *Ultrasound*
**Ultrasound - Summary**: * Therapeutic use of soundwaves * Produces thermal and nonthermal effects * Continuous duty cycle = thermal effects, 20% duty cycle = nonthermal effects. * Frequency based on tissue depth, 3 MHz = 1-2 cm, 1 MHz = up to 5 cm. * Intensity depends on frequency and whether thermal effects sought. * Robust evidence lacking, likely a situationally appropriate modality.

DPT 690 - PT Interventions II (13 decks)

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