85 notecards = 22 pages (4 cards per page)
In a stenotic vessel explain what happens to velocity, pressure and volume.
Which reaction occurs at a stenosis?
a drop in pressure
As the average speed rises the Reynolds #
Reynolds # formula
(Velocity * Density * Diameter)/ Viscosity
As the diameter increases what happen to Reynolds #
As the viscosity increases what happen to Reynolds #
Doubling the radius of a vessel Decreases resistance to
1/16 of the original value
How many transducers does CW have?
Can CW determine depth?
Which forms of ultrasound uses the Doppler effect?
cw, pulsed-wave, color-flow, color doppler energy (NOT STATIC) Doppler would be useless in
Pulsed wave disadvantage
Continuous wave disadvantage
range ambiguity (depth confusion)
Can distinguish movement in both directions
Small gate (sample volume)
Gives you High Signal: Low Noise
With PW Doppler, the pulser generates _____ cycles of pulses.
The longer the vessel/tube the ______ the resistance
Flow at the beginning of the tube is likely to be ______
Flow going in same direction is ______
If you double pressure what happens to volume?
Pressure is directly proportionate to Volume (flow)
If length of tube increases, what will happen to Flow will?
w will decrease. Flow and Length are indirectly proportionate.
If you increase viscosity, what happens to velocity?
The inertia of the blood and vessels causes pressure to _______ when the velocity of blood flow increases
Pressure that is static flow
Reynolds number has NO UNIT
Venous flow is non ______
Blood flows from _____ pressure to ____ pressure
high to low
Viscosity can be defined as
the measurement of a liquid's resistance to flow
Turbulent flow =
Receiver is moving away from the Source
Moving in opposite direction
the max neg – Doppler shift
Correction line (angle) must be aligned _____ to correct
Doppler shift formula
Doppler shift = 2V cos0 Fo/C
The Doppler shift frequencies at 90 degrees =
Increasing the ensemble length ________ the frame rate.
Increasing ensemble length improves color sensitivity and accuracy and decreases _______
Color map baselines are always represented by ______.
black.(NO Doppler shift)
Steering the color window(gate, or box) to the right or left produces an _______ frame rate.
Compared with Doppler-shift imaging, Doppler-power imaging is more ______.
Color Doppler frame rates are ______ gray-scale rates
Frame rate =
frames per second
An earlier gate time means a ________ sample volume depth.
Flow reversal in diastole indicates _____ distal resistance.
what is the significance of large ensemble length
more sensitivity - ability to detect low flow
Decreasing the size of your color box has what effect on framerate
Increases frame rate
Increasing the size of B-mode area does what to frame rate
decreases Frame rate
Changing Doppler gain has what effect on framerate
Changing Doppler gain –has NO effect on frame rate
Which one has the slowest flow? looking at map
It will be the scale/map with the lowest #
What changes the colors in an image?
If venous flow is on the top , and goes to bottom of baseline how would you get it back to normal(correct it)?
Changing sweep speed does not affect ____ or _____ It changes amount of waves displayed
height or width
CW duty factor
100% or 1
If all the blood in vessels in a color box (gate)were traveling same speed—Spectral broadening _____ occur
Spectral Doppler is still SPECTRAL Doppler even if edges are colored..(don’t be tricked)
The removal of unwanted noise /clutter
The process of transforming the returning Doppler signals is accomplished by what
The horizontal scale represents
Changes in velocity & Frequency
Power Doppler doesn’t report
CW is used in _____ Doppler instruments
(know facts about CW )
How many pulses in color flow Doppler to write 1 line?
5 - 30 , 10 - 20 average
How do you turn on gate location?
turn on spectral
How many pulses in B-mode to write 1 line?
In Doppler shift blood flow moving away from the transducer will ______ the frequency of the sample wave
Opening the gate
Gate determines ____
depth (time and depth)
Advantage of PW
Advantage of CW
The range of velocity is controlled by
Y axis =
90 degree angle=
As angle increases—
it miscalculates more
Cosine of 60 is---
True or false
If the cosine increases what happens to the Doppler shift?
What is the correct Doppler Shift equation?
FD = (2 * V* cos0 * f0)/c
Velocity calculation error increases as the cosine angle _____.
True or False
The ensemble length is the _______
48.Primary colors are
the 3 basic hue colors
freezing the grayscale like in m mode, _______ the frame rate
INCREASES the frame rate
51 no motion=no Doppler shift=black on color map