Receiver Frequency Range; Harmonic Imaging (Hi) - GE Voluson S6 Basic User Manual

6.2.8 Receiver Frequency Range

6.2.9 Harmonic Imaging (HI)

Voluson® S6/S8 Basic User Manual
5433669-100 Revision 4
Use the [Foc.Zones] control key to select the number of focal zones.
The possible number of focal zones depends on the probe in use. Arrows at the left side of
the 2D image mark the active focal zones by their position.
Use the [Focus Depth] digipot to select the depth position of the current focus one(s). The
depth position(s) of the focal zone(s) is marked by the marker arrows.
Behaviour of the Focus:
In all boxes like Zoom box, CFM box, CF, PD, HD Flow or TD the default position of the focus
is centered (nearest focus position to the middle.) You can adjust focus position manually
using the [Focus Depth] digipot. When you change box position after adjusting focus position,
the focus will return to its default position.
Remarks:
•
After selection of focal zones the maximum possible acoustic output can be adequately
reduced.
•
The more focal zones are set, the lower is the frame rate.
The "Frequency range" function allows for the fast adjustment of high resolution/lower
penetration, mid resolution/mid penetration, or lower resolution/ high penetration for the 2D
image. From the transducer's broadband signal a certain start frequency and start bandwidth
is extracted and then continuously changed over depth. Every transducer has a set of three
fixed receive settings which are easily controlled by switching the [Frequency] key.
Use the [Frequency] control to adjust the range of the receive frequency. Three positions are
possible: Resolution, Normal, Penetration
Remarks:
•
The selected frequency range is displayed on the screen.
•
The frequency range is displayed in 2
5.0Mhz 7.5 ...... start frequency 5.0 ...... end frequency
Tissue not only scatters back echoes with the nominal transmitted frequency but also with
double, threefold, fourfold and so on (harmonic) frequencies, as a result of a physical effect
called "non-linear propagation". Coded Harmonic Imaging delivers better grayscale contrast
compared to standard ultrasound imaging. This technique has proved to be particularly useful
for difficult-to-image patients and furthermore is less prone to artefacts.
nd line of the B mode Image Info area: e.g.: 7.5 -
2D Mode
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