2. Steps for optimization
. Zoom to the area of interest ..
. adjust the focus.
.apply the colour Doppler.
- narrow the color box .
.adjust the gain.
.Apply the pulsed wave.
-adjust the gate to cover the vessel.
.adjust the angle.
.adjust the velocity scale (PRF ).
.Adjust the baseline &
f
ilter.
6. Power Doppler (PD)
. No illeasing .
. Angle independent.
. The sensitivity mor than color Doppler
for detection of low velocity vessels.
. Distinguish pre- occlusive from
occlusive lesions .
. Superior depiction of plaque surface
morphology.
. Useful in imaging tortious small vessels
. Used to look for tumor vessels inside
the organs
7. The key board of us machines
C= color
pw = pulsed wave
PW = power Doppler
9. Steps for optimization
Zoom and focus
. Zoom at the area of
interest
- set the focus
At the region of interest
10. Color Doppler ( C )
Operator press ( C) button Color box appear on the screen the adjusting
from( set) and move it by trackball
should be small and super
f
icial
11. Adjusting color gain
Color gain should be set as high as possible
Without displaying random color speekles
12. Apply PW
Adjusting Sample Gate — size and position
The size of the gate about 2 - 5 mm
It must to be small
With small vessel
for example
2 mm size in ductus
.the gate size is wide with a big
vessel
For example
3 mm size in umbilical artery
The gate should
be positioned over
the central part of
the studied
vessels
13. Angle of insinuation
- the angle between he ultrasound beam
and the blood
f
low inside the vessel 60 <
The closure to zero more accurate
>60 cause signi
f
icant underestimation of
the velocity
No di
ff
erent
change in pi
and Ri value
value
between the
angle
30 0r 50
Degree
14. Adjusting color velocity scale
(PRF)1–High scale velocity
( absence of
f
low)
2–optimum scale and normal
vasclar
f
low
3–low scale
( color aliasing )
PRF
Is the number of
ultrasound pulses
estimated
By the transducer
over designated
period of time .
— after increasing
the velocity scale
Automagically
increases the PRF
16. Adjusting base line
Normal basline
line
Inverted line is
corrected by inverter
button in key board
Dropped
baseline
Invert button
17. Changing wall
f
ilter
Loss of low
velocity
f
low of
wave form
above base line
Wave form appear
above baseline
when reducing
wall
f
ilter
For
example
18. To get rid of aliasing
. if the frequency
exceeds half PRF
Aliasing occurs
The correction of
aliasing by
.change the velocity-
scale
. Change the base line
. Use a lower us
frequency
