Full Digital Color Doppler Ultrasonic Diagnostic Instrument (Vet) User’s Manual V1.00
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8
Harmonics
2-level
Switch
the
work
frequency
and
harmonic frequency.
9
Acoustic
Power
4-level
AP25, AP50, AP75, AP100
10.3.4 M mode
Display adjustable parameters in M mode
For M images, through “Parameters” menu user can adjust “Dyn Range”, “ Edge”, “Comp Curve”,
“IP”, “M speed” and “M Mode Menu”; or turn
knob to adjust the image’s total gain; or turn
knob to adjust the image’s dymanic range.
10.3.5 CFM mode
CFM (Color flow mapping) mode is easy to observe the information of color flow, and can judge the
flow’s direction and velocity by color. In general, the color above color-bar baseline indicates the direction of
blood flowing to the probe; the bottom color indicates the reverse direction of blood flowing to probe; Color
is closer to the top color of color-bar, the velocity of blood is faster; closer to the color of color-bar baseline,
the velocity more slowly.
To get good blood flow information, the color flow adjustment is particularly important. Please
carefully read the following content before examination, and as a reference in the actual examination.
1). Color gain
The color’s brightness is in proportion to the blood flow velocity. The velocity is higher, the color’s
brightness is stronger; the lower velocity is, the weaker color’s brightness is.
Red and blue colors clutters will appear in the extravascular when the gain is too large; too small gain,
the blood flow is deficiency in the intravascular (especially check the small vessels and low-velocity
blood flow). When observing the blood flow figure, usually reduce the appropriate gain, decease the
affect of strong reflected signal in the vessel wall, then increase the color gain until clutters appearing
in the extravascular, then adjust the color gain back and forth until the color clutters just disappeared.
2). Velocity range, also known as range. In actual it adjusts PRF. Velocity range is set too high, the blood
flow is not satisfied, particularly difficult to detect low-velocity blood flow; be set too low, it will occur
color aliasing. Velocity range should be adjusted to maximize the display of low-velocity blood flow, but
not to appear color inversion. In the absence of blood mixed, satisfactory blood flow imaging should be
good filling within the lumen; no color inversion; due to higher velocity of flow, the color in the lumen
central part is brighter, such as red blood also with yellow.
3). Wall filter. In Doppler ultrasound, the received signals by probe are from red blood cells, but also mixed
with reflective Doppler signal generated by vessel wall and surrounding tissue. The reflective signal is
characterized by a low frequency, but echo signal intensity is larger than blood flow signal; it will
interfere with blood flow detection. The role of the filter is to filter out the reflective Doppler signal,
namely, filter out low-frequency echo signal not generated by blood flow, so that the blood flow signals
(low echo intensity and high velocity) can pass. The instrument has different filtering-levels by filtering
degree. The bigger level filter not only filters out non-blood flow, but also filters out low-velocity blood
flow signal.
Selecting the filter should be considered the inspection object. In the abdomen field, unless detecting
high-velocity large vessels such as abdominal aorta, the filer is generally adjusted to the smaller level,
especially in the detection of vein blood flow. The level of filter is smaller; the display of low flow
steadily is abundant.
4). Frame rate. To get a good real-time in the examination, it should be kept a certain frame rate. If the frame
rate is too low, the real-time is too poor, and difficult to distinguish the low blood flow signal and color
clutter. The frame rate is in proportion to PRF, the higher PRF is, the higher frame rate is, but consequent
Attention:
In real time M mode, only has “Parameters” menu. You also can move the
trackball to select the desired menu-item, when appears icon on the menu-item,
press
/
key or press
keys to adjust the parameters.