Ultrasound Flashcards
When acoustical energy is absorbed by tissue what is created?
Thermal energy is created
Are tendons and ligaments dense tissues?
Yes
Compression happens in what type of tissue?
Dense tissue
Rarefraction happens in what type of tissue?
Less dense tissue
What are the principles of acoustic energy?
- Propagation of US waves
- Production of compression and rarefractions
- effect on US on various tissue densities
Is ultrasound more effective at heating dense tissues or less dense tissues?
Dense tissues
What does alternating current cause the crystal in US sound head to do?
Causes the crystal to expand and compress at a fast rate
What is the following a definition of?
Drawing in & drawing out of the shape of crystal
Piezoelectric effect
What is the ERA?
ERA = effective radiating area
Smaller than the actual size of the sound head
What are the frequencies that the ultrasound head can be placed at?
1 MHz, 3 MHz, 3.3 MHz
Frequency and depth of penetration are ____ ____
inversely proportional
Does tissue absorb heat faster at 1 MHz or 3 MHz?
3 MHz
A frequency of 1 MHz will penetrate how deeply?
6 cm deep
A frequency of 3 MHz will penetrate how deeply?
2.5 cm deep
What are the guidelines for intensity?
No guidelines - follow how to pt feels and is responding to treatment
What is the unit of measurement of dosage?
Joules (J)
What mode is this?
US delivered at constant energy level throughout the treatment
Continous
What mode is this?
energy flow cycles on/off
Pulsed
What part of the Pulsed Mode of US is this?
Time energy is flowing?
Pulse duration
What part of the Pulsed Mode of US is this?
‘on’ time (flow) + ‘off’ time (no flow)
Pulse Period
What part of the Pulsed Mode of US is this?
‘on’ time / ‘on’ time + ‘off’ time
Duty cycle
What is the following a definition of?
nonuniformity of acoustical energy at different parts of the collimated beam
Beam Nonuniformity Area (BNR)
A low BNR (3 or less) will do what?
Minimize the pt’s discomfort
What is this purpose for?
Distribute ‘hot spots’ around the treatment area and avoid burns (discomfort) by continually moving the ultrasound head
Beam Nonuniformity Area (BNR)
How big should the treatment area for US be?
No larger than 2-4x the treatment area (ERA)
What heats faster with ultrasound, muscle or achilles tendon?
Achilles tendon
What angle should the incident angle be at to avoid reflection of the US waves
90 degrees
How fast should the sound head be moving during treatment?
2 cm/sec to 6 cm/sec
What research design is the following?
RCT’s with an active interventin, appropriate control groups, and subjects randomly assigned to each group
Class I
What research design is the following?
Active intervention and control group without randomization to groups
Class II
What research design is the following?
Active intervention but without control groups; these are often single group designs
Class III
What research design is the following?
Single-subject ‘experimental’ designs and observational studies that involve case control, cohort, and case studies
Class IV
What type of theraputive effectiveness is this?
number of studies reporting improvement is greater or equal to 60%
Substantiated
What type of theraputive effectiveness is this?
number of studies reporting improvement is less than 60% but greater than or equal to 40%
Conflicting
What type of theraputive effectiveness is this?
number of studies reporting improvement is less than 40%
Unsubstantiated
What type of theraputive effectiveness is this?
< 5 studie of any type
Lack of evidence
What type of Strength of evidence is this?
50% or more of the studies are in class I
Strong evidence
What type of Strength of evidence is this?
> 50% of the stuides are in class I, II, and III
Moderate evidence
What type of Strength of evidence is this?
> 50% of the studies are in class IV
Weak evidence
What type of Strength of evidence is this?
fewer than 5 studies reporting on the outcomes under investigation
Lack of evidence
Which part of the body does this evidence support?
- benefit for pain
- conflicting evidence for increased pain threshold
- unsubstantiated effect on cervical ROM
Myofascial pain
Which part of the body does this evidence support?
- conflicting evidence
- no definitive conclusions
Back pain
Which part of the body does this evidence support?
- Insufficient evidence for thermal US
- no evidence of pulsed information US
Shoulder pain
Which part of the body does this evidence support?
- little evidence to support use of theraml or nonthermal US
Lateral epicondylitis
Which part of the body does this evidence support?
- strong substantial evidence for thermal US
- Reduction of pain and improved functional outcomes
Carpal tunnel syndrome
Which part of the body does this evidence support?
- Parameters widely varied
- Evidence for thermal US for pain & dysfunction
Calcific tnedonitis
Are the following contraindicatios or precautions? continous or pulsed?
- Pregnancy
- Active bone growth at epiphysis
- cancer
- tuberculosis infection
- hemorrhagic conditions
- impaired circulation
- myositis ossificans
- deep vein thrombosis
- acute injury
- recently irradiate tissue
- impaired sensation or cognition and communication
- skin disease
- pacemaker
- reproductive organs
- anterior neck
- metal implants over chest, heart or head
Contraindications of continous US
Are the following contraindicatios or precautions? continous or pulsed?
- Plastic or cemented implants
- spinal cord and superfical or regenerating nerves
Precautions of continous US
Are the following contraindicatios or precautions? continous or pulsed?
- pregnancy
- cancer
- hemmorhagic conditions
- myositis ossifcans
- deep vein thrombosis
- recently irrated tissue
- pacemaker
- reproductive organs
- eyes
- anterior neck
- metal implants over heart, head, or chest
Contraindications of Pulsed US
Are the following contraindicatios or precautions? continous or pulsed?
- Active bone growth at epiphysis
- areas of infections
- acute injury
- impaired sensation
- impaired cognition or communication
- impaired circulation
- skin disease
- plastic or cemented implants
- spinal cord and superficial or regnerating nerves
Precautios of Pulsed US
What is the following a definition of?
- Use of US to enhance delievery of topical agents through the skin
- ‘pushing’ molecules and increased permeability
- poor evidence for either mechanism
Phonophoresis
