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==Sound Waves==  
 
==Sound waves==  
*Ultrasound uses high frequency energy to create sound waves, characterized by
*Ultrasound uses high frequency energy to create sound waves, characterized by
**frequency: number of cycles per second (Hz)
**frequency: number of cycles per second (Hz)
Line 11: Line 11:
**amplitude: height of sound wave (decibels)
**amplitude: height of sound wave (decibels)


==Ultrasound and tissue interaction==
==Ultrasound And Tissue Interaction==
*reflection
*'''Reflection'''
**occurs when an ultrasound wave hits tissue.  Part of the wave is reflected back to the transducer
:**occurs when an ultrasound wave hits tissue.  Part of the wave is reflected back to the transducer
**tissues with greater density reflect a greater portion of the beam
:**tissues with greater density reflect a greater portion of the beam
**tissues at a 90 degree angle to the beam reflect a greater portion of the beam
:**tissues at a 90 degree angle to the beam reflect a greater portion of the beam


*acoustic impedance
*'''Acoustic impedance'''
**tissues can be defined by their individual acoustic impedance
:**tissues can be defined by their individual acoustic impedance
**AI = density x acoustic velocity
:**AI = density x acoustic velocity


*scatter
*'''Scatter'''
**small structures lead to scattering of the ultrasound signal
:**small structures lead to scattering of the ultrasound signal
**scattering radiates the beam in all directions, very little reaches back to the transducer
:**scattering radiates the beam in all directions, very little reaches back to the transducer


*refraction: ultrasound waves can be deflected as they pass into a medium of different acoustic impedance
*refraction: ultrasound waves can be deflected as they pass into a medium of different acoustic impedance


*attenuation
*'''Attenuation'''
**when sound travels through a medium, intensity diminishes with distance
**when sound travels through a medium, intensity diminishes with distance
**caused by absorption of the energy by the tissues, and conversion to heat
**caused by absorption of the energy by the tissues, and conversion to heat
**also affected by acoustic impedance and mismatch in impedance between adjacent structures
**also affected by acoustic impedance and mismatch in impedance between adjacent structures


==Ultrasound set-up==
==Ultrasound Set-Up==


*Energy source
*Energy source
*Transducer: converts electrical pulses to vibrations and returned vibrations back to electrical pulses
*'''Transducer'''
**piezoelectric crystals
:It converts the electrical pulses to vibrations and returned vibrations back to electrical pulses
***found inside the transducer
 
***compress and expand the electric current that is applied, generating a sound wave
*'''Piezoelectric crystals'''
***same crystals also act as receivers.  An electric current is generated when a reflected wave hits a crystal
:*It is found inside the transducer
:*It compresses and expand the electric current that is applied, generating a sound wave
:*Same crystals also act as receivers.  An electric current is generated when a reflected wave hits a crystal.


Image formation: based on the time interval between the ultrasound transmission and the arrival of the sound wave back to the transducer
Image formation: based on the time interval between the ultrasound transmission and the arrival of the sound wave back to the transducer


==Resolution==
==Resolution==
*axial- along the length of the ultrasound beam
*Axial- along the length of the ultrasound beam
*lateral- side to side resolution of the 2D image
*Lateral- side to side resolution of the 2D image
*elevational- the thickness of the tomographic slice
*Elevational- the thickness of the tomographic slice


==Basics of Echocardiography==
==Basics of Echocardiography==
<div class="mw-collapsible mw-collapsed">


===Basics of Echocardiography-Part 1===


'''Basics of Echocardiography'''-Part 1
<div class="mw-collapsible-content">
 
'''Basics of Echocardiography'''-Part 1-Series 1
{{#ev:youtube|QdkJ6qzMfNE}}
{{#ev:youtube|QdkJ6qzMfNE}}




'''Basics of Echocardiography'''-Part 2
'''Basics of Echocardiography'''-Part 1-Series 2
{{#ev:youtube|h4dZmbfXKJQ}}
{{#ev:youtube|h4dZmbfXKJQ}}


</div></div>
<div class="mw-collapsible mw-collapsed">


'''Basics of Echocardiography'''-Part 3
===Basics of Echocardiography-Part 2===
 
<div class="mw-collapsible-content">
 
'''Basics of Echocardiography'''-Part 2--Series 1
{{#ev:youtube|SaORcN29CtM}}
{{#ev:youtube|SaORcN29CtM}}




'''Basics of Echocardiography'''-Part 4
'''Basics of Echocardiography'''-Part 2--Series 2
{{#ev:youtube|zZVBN2cdqSo}}
{{#ev:youtube|zZVBN2cdqSo}}
</div></div>


==Fetal Echocardiography==
==Fetal Echocardiography==
<div class="mw-collapsible mw-collapsed">
===A Descriptive Case Presentation ===
<div class="mw-collapsible-content">
* '''A Descriptive Case Presentation'''
{{#ev:youtube|ZIk9GhWqqfE}}


* Transposition
</div></div>
<div class="mw-collapsible mw-collapsed">


<Youtube v=Rkm8e9q1GSc/>
===Transposition===


* A Descriptive Case Presentation
<div class="mw-collapsible-content">
* '''Transposition'''
{{#ev:youtube|Rkm8e9q1GSc}}


<Youtube v=ZIk9GhWqqfE/>
</div></div>
<div class="mw-collapsible mw-collapsed">


* Fetal Cardiac Myxoma
===Fetal Cardiac Myxoma===


<Youtube v=SdNw9yH9jBg/>
<div class="mw-collapsible-content">
* '''Fetal Cardiac Myxoma'''
{{#ev:youtube|SdNw9yH9jBg}}
 
</div></div>


==The Guide to Pediatric Echocardiography==
==The Guide to Pediatric Echocardiography==
<div class="mw-collapsible mw-collapsed">


<Youtube v=mquEA6l2afs/>
===Pediatric Echocardiography===


<div class="mw-collapsible-content">
{{#ev:youtube|mquEA6l2afs}}


</div></div>
==References==
{{Reflist|2}}
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[[Category:Cardiology]]
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[[Category:Imaging]]
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Latest revision as of 04:45, 15 March 2016


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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Ahmed Zaghw, M.D. [2]

Sound Waves

  • Ultrasound uses high frequency energy to create sound waves, characterized by
    • frequency: number of cycles per second (Hz)
    • wavelength: distance between excitations (mm)
    • amplitude: height of sound wave (decibels)

Ultrasound And Tissue Interaction

  • Reflection
    • occurs when an ultrasound wave hits tissue. Part of the wave is reflected back to the transducer
    • tissues with greater density reflect a greater portion of the beam
    • tissues at a 90 degree angle to the beam reflect a greater portion of the beam
  • Acoustic impedance
    • tissues can be defined by their individual acoustic impedance
    • AI = density x acoustic velocity
  • Scatter
    • small structures lead to scattering of the ultrasound signal
    • scattering radiates the beam in all directions, very little reaches back to the transducer
  • refraction: ultrasound waves can be deflected as they pass into a medium of different acoustic impedance
  • Attenuation
    • when sound travels through a medium, intensity diminishes with distance
    • caused by absorption of the energy by the tissues, and conversion to heat
    • also affected by acoustic impedance and mismatch in impedance between adjacent structures

Ultrasound Set-Up

  • Energy source
  • Transducer
It converts the electrical pulses to vibrations and returned vibrations back to electrical pulses
  • Piezoelectric crystals
  • It is found inside the transducer
  • It compresses and expand the electric current that is applied, generating a sound wave
  • Same crystals also act as receivers. An electric current is generated when a reflected wave hits a crystal.

Image formation: based on the time interval between the ultrasound transmission and the arrival of the sound wave back to the transducer

Resolution

  • Axial- along the length of the ultrasound beam
  • Lateral- side to side resolution of the 2D image
  • Elevational- the thickness of the tomographic slice

Basics of Echocardiography

Basics of Echocardiography-Part 1

Basics of Echocardiography-Part 1-Series 1 {{#ev:youtube|QdkJ6qzMfNE}}


Basics of Echocardiography-Part 1-Series 2 {{#ev:youtube|h4dZmbfXKJQ}}

Basics of Echocardiography-Part 2

Basics of Echocardiography-Part 2--Series 1 {{#ev:youtube|SaORcN29CtM}}


Basics of Echocardiography-Part 2--Series 2 {{#ev:youtube|zZVBN2cdqSo}}

Fetal Echocardiography

A Descriptive Case Presentation

  • A Descriptive Case Presentation

{{#ev:youtube|ZIk9GhWqqfE}}

Transposition

  • Transposition

{{#ev:youtube|Rkm8e9q1GSc}}

Fetal Cardiac Myxoma

  • Fetal Cardiac Myxoma

{{#ev:youtube|SdNw9yH9jBg}}

The Guide to Pediatric Echocardiography

Pediatric Echocardiography

{{#ev:youtube|mquEA6l2afs}}

References


Template:WikiDoc Sources CME Category::Cardiology