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Ultrasound Modes

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Mode 

A mode is an operational state that a system has been switched to. A normal mode occurs when all parts of a system oscillate with the same frequency.
For example, a standing wave is a continuous form of normal mode. In a standing wave, all the parts are oscillating in the same frequency and phase but each has a different amplitude.

• View the NEWS results for 'Mode' (7).Open this link in a new window.

• View the DATABASE results for 'Mode' (144).Open this link in a new window.

Ultrasound Imaging Modes 

Ultrasound imaging is excellent for diagnosing cysts and other fluids in soft tissue. For ultrasound imaging or ultrasonography, different modes are used to examine the arterial/venous system, heart, pancreas, urinary system, ovaries, spinal cord, joints and more.
Power levels, frequencies used, amplification, and beamforming determine the clarity of the image. These things are controlled by the sonographer, interacting with the properties of the ultrasound machine.

Various imaging modes:
point A-mode;
point B-mode;
point QB-mode;
point M-mode;
point real-time mode;
point pulsed wave Doppler;
point continuous wave Doppler;
point color Doppler;
point color power Doppler;
point duplex.

• View the DATABASE results for 'Ultrasound Imaging Modes' (6).Open this link in a new window.

 Further Reading:
  News & More:
Module 1: Basic A-scan Biometry Section 1: Basic ConceptsOpen this link in a new window
   by www.eyetec.net    
Doppler Ultrasound 

Doppler ultrasound is a medical imaging technique for calculating the relative velocity between two points by measuring the frequency shift of a sound wave transmitted from one point to the other, based on the Doppler effect. Continuous or pulsed Doppler is frequently used to examine cardiovascular blood flow. The combination of routine 2D-mode and Doppler ultrasound allows a complete evaluation of the heart's anatomy and function (including the fetal heart). See also Doppler Fluximetry in Pregnancy.
Doppler ultrasound depends on the fact that if a moving object reflects the ultrasound waves, the echo frequencies are changed. A higher frequency is created if the object is moving toward the probe//transducer and a lower frequency if it is moving away from it. How much the frequency is changed depends upon how fast the object is moving. Doppler ultrasound shows the different rates of blood flow in different colors on a monitor in real time.
The major Doppler parameters are the peak systolic velocity and the end-diastolic velocity. The peak systolic velocity ratio compensates the variability between different patients and instrumentations.

Different Doppler and duplex techniques:
list_point color Doppler;
list_point color power Doppler;
list_point continuous wave Doppler;
list_point contrast enhanced Doppler imaging;
list_point directional color power Doppler;
list_point duplex;
list_point harmonic power Doppler;
list_point pulse inversion Doppler;
list_point pulsed wave Doppler;
list_point spectral Doppler;
list_point transcranial Doppler.

• View the NEWS results for 'Doppler Ultrasound' (4).Open this link in a new window.

• View the DATABASE results for 'Doppler Ultrasound' (23).Open this link in a new window.

 Further Reading:
  Basics:
Noninvasive Evaluation of Peripheral Arterial DiseaseOpen this link in a new window
   by ej.rsna.org    
  News & More:
Principles in Doppler EchocardiographyOpen this link in a new window
   by www.echoincontext.com    
Evaluation of lower extremity bypass grafts with use of color duplex sonographyOpen this link in a new window
Thursday, 30 June 2005   by radiographics.rsna.org    
Carotid artery color doppler ultrasound: 80-90% stenosis of the proximal internal carotid artery secondary to large atherosclerotic plaquesOpen this link in a new window
   by rad.usuhs.mil    
Duplex 

Duplex ultrasonography (duplex scan) consists of two ultrasound modalities to study blood flow and the perivascular tissue. This includes B-mode / gray scale imaging used in combination with spectral Doppler / pulsed-wave Doppler.
The real-time visualization of the vessels and tissue by the B-mode component improves the PW Doppler positioning and the direction of blood flow can be inferred. The angle between the direction of the PW Doppler signal and the estimated direction of blood flow can be measured.
Duplex techniques are available on phased array, linear array, and mechanical scanners. A phased array probe is able to create nearly simultaneous images and flow information. A linear array transducer can also do this if the Doppler probe is attached separately to one end of the scanhead. A mechanical transducer freeze the image; the crystals must be static to produce a Doppler image. The first two transducers are therefore the best choice for Duplex.
See also Compound B-Mode, and Duplex Scanner.

• View the DATABASE results for 'Duplex' (10).Open this link in a new window.

 Further Reading:
  Basics:
MR angiography effective for diagnosing carotid artery stenosis - Patient Oriented Evidence That MattersOpen this link in a new window
September 2003   by www.findarticles.com    
Contrast-Enhanced Transcranial Color-Coded Duplex Sonography in Ischemic Cerebrovascular DiseaseOpen this link in a new window
Monday, 1 December 1997   by stroke.ahajournals.org    
  News & More:
Optimizing Doppler and Color Flow US: Application to Hepatic Sonography(.pdf)Open this link in a new window
   by radiographics.rsna.org    
Ultrasonographic fata morganaOpen this link in a new window
2003   by ndt.oxfordjournals.org    
  Basic Modes I top
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