Deep Heat: Ultrasound Flashcards
When should you NOT use deep heat ultrasound? (6)
- ANY musculoskeletal problem
- Pain
- Soft tissue injury
- LBP
- Frozen Shoulder
- Acute Ankle Sprain
Why do you not use deep heat ultrasound on the conditions like pain, soft tissue injury, musculoskeletal problems, etc.?
Research shows NO diff. with or without
It is passive
Considered not a skilled service
No good quality study has demonstrated a clinically significant benefit
Wasting healthcare $ providing US for lumbar spine conditions
What is ultrasound?
Acoustic energy/vibrations via sound waves causing mechanical pressure waves at ultra high frequency
What is ultrasound’s frequency requirement?
> 20,000 Hz considered US
Ultrasound can produce ____ or _____ effects
thermal; mechanical
When using ultrasound, you use a gel because the sound waves require what to travel through?
An elastic medium
US converts electrical energy to
sound waves
Sound energy travels faster through what kind of materials?
denser
Transmission of acoustic energy requires a medium. What is NOT a good conductor of waves?
air
Sound waves vary in a ______ pattern
sinusoidal
Condensations are areas of
compression or increased molecular density
Rarefactions are areas of
decreased molecular density
What are 3 main parts of the US wave?
FMI
- Frequency
- Mode
- Intensity
Deeper penetration is at ___ MHz and reaches about ____ inches. You’d want to use this on muscles like the soleus or deep hip rotators
1 MHz; 1-2 inches
Superficial penetration is at ____ MHz and is absorbed more easily, raises ____ faster and has less penetration. You’d want to use this on conditions like plantar fasciitis.
3; temperature
What are the 2 modes of US?
- Continuous
2. Pulsed
What is the continuous US mode?
uninteruppted stream of sound waves
What is the pulsed US mode?
periodic interupptions in sound waves
What is the duty cycle?
fraction of time during a single pulse period that US beam is present
% of pulsed duration
on-time to the sum of on-time plus off-time (10 sec on, 30 sec off so sum = 40 sec total time –> 10/40 = 25% duty cycle)
The intensity of US is the strength of the
wave
The intensity of US is determined by the
quantity of energy or acoustic power
The intensity of US is measured in
watts (W)
Intensity is not uniform across
sound head
The Effective Radiating Area (ERA) is a measure of the actual what?
Cross-sectional area of the US beam as it exits the metal plate
expressed in square centimeters
Intensity equation
W/cm^2
US can be transmitted, absorbed, reflected and ____; it depends on the ____ and tissue ____ (impedance).
refracted; angle; type
Acoustic impedance is
material / tissue’s ability to transmit sound
molecular density and structure of material/tissue
If acoustic impedance is low, transmission is ___ and materials absorb ____ sound
high; little
Greater changes in impedance = greater % of energy is
reflected
i.e. muscle/bone interface
The depth of penetration is ____ related to frequency
inversely
Lower frequency causes ___ penetration
deeper
Higher frequency causes ____ penetration
not increase/decrease; think about what layer is penetrated with a higher freq on US machine
superficial
Due to increased attenuation (decrease in sound energy by increased absorption/dispersion), higher frequency US is more
superficial
Factors affecting absorption of US waves/energy include
- attenuation
- US frequency
- Mode
- Intensity of US wave
- Tissue composition
- Medium used for transmission
- Angle of US beam
The angle of the US beam should be ____ deg from perpendicular
15
What are the 6 physiologic effects of US?
TM MC HN
- Thermal
- Mechanical
- Muscular
- Connective Tissue
- Hemodynamic
- Neurologic
The thermal effects of US include
deep heating
increased metabolic rate, decreased muscle spasm/pain, increased blood flow, increased collagen extensibility and decreased sympathetic activity
What are the 2 main mechanical effects of US (non-thermal)?
hint: MC
- Microstreaming
2. Cavitation
What is microstreaming?
Small magnitude movements of ions and cellular fluids that alter cellular activity and cell membrane permeability
What is cavitation?
small gas bubbles present in body fluids are subject to compression during condensation/expansion during rarefactions when exposed to US
CAUTION: when exposed to high intensity US, it may cause violent collapse or implosion of gas bubbles which leads to tissue destruction
Rate and magnitude of mm temp depend upon (3)
IDF
- intensity
- duration
- frequency
No studies completed looked at ____ of temp elevation in human mm after US treatment
duration
Connective tissue heats up faster and to a higher temp than mm because connective tissue is more ____, has higher _____ content and is more __vascular
dense
collagen
avascular
The thermal mechanism of US include
Increased tissue temperature as US energy is absorbed
Local blood flow then increased to area to dissipate heat
Non thermal mechanisms of US on hemodynamics include
- Reflexive vasodilation
2. Local histamine release changes vascular tone
Regardless of mechanism, blood flow returns to baseline less than ___ after US
1 minute
Motor nerve conduction velocities (MNCV) change during US can be
increased, decreased or stay the same
Sensory nerve conduction velocities (SNCV) appear to ____ with thermal US
increase
___ perception also can be altered in US
pain
Thermal is achieved with _____ US
continuous
0.75-3.0 w/cm2
Non-thermal is achieved with ____ US or ___ intensity continuous US
pulsed; low
The gentle tissue temperature rise should be ___ enough not to cause pain, ____ enough for depth of penetration and ____ enough for heating to occur
low; high; long
What are the main clinical uses of US?
- Inflammation
a. Pain
b. Edema - Tissue Healing
For tissue healing, what does US promote?
- # of tissue repair cells
- collagen
- protein synthesis
Pain is ____ and Edema is ____ effect-wise with US
thermal; non-thermal
US ___ circulation, ___ mobility, and ____ extensibility of collagen
increases; increases; increases
What are the main 5 indications for using US?
- Contractures/scarring
- Chronic arthritis
- Muscle strain/spasm
- MM Guarding/trigger pts
- Subacute/chronic inflammation
What are contraindications for using US?
- Pacemaker
- Pregnancy
- Malignancies/tumors
- DVT/thrombophlebitis
- Infected areas
- Spinal laminectomy
- Growing bone/epiphyseal plate not closed
- Areas tending to bleed
- Eyes
- Over heart, carotid sinus, cervical ganglia
What are precautions to using US?
- Unhealed Fx sites
- Primary repair of tendon or ligament
- Osteoporosis
- Plastic implants
- Metal implants
When using indirect contact, you either are doing ______ or _____
water immersion; gel pad
Indirect contact only delivers how much energy vs direct contact?
32%
Phonophoresis uses what in addition to US gel?
hydrocortisone (10%) or lidocaine
DON’T DRAG _____ in the gel for US
tip of gel bottle
If selecting pulsed US, you also have to select
the duty cycle
The size of the treatment area should be ____x size of the soundhead (____x ERA)
2-3; 3-4
Pressure on the transducer should ____ skin and be moving ______
indent; continuously
The appropriate time using US should be _____ minutes per site
5-10
Less than ____ minutes shows NO physiological effects
3
__ MHz takes 10 minutes to reach a therapeutic temperature, so ___ MHz is advised as it is faster
1; 3
What 2 motions are used with US?
Either longitudinal stoking or circular movements
The US Intensity should be ____ with more acute conditions and ____ with chronic conditions/CT shortening
lower; higher
The transducer/sound head MUST be…….when starting
in contact with skin
otherwise crystal will break with air contact
