When will the Doppler shift be the highest?
A.when the beam is parallel to the direction of flow
B.when the beam is at a 45 degree angle to flow
C.when the beam is perpendicular to the direction of flow
D. Doppler shift is unrelated to beam angle Correct Answer: A.when the beam is parallel to ...
spi ultrasound physics review| 296 questions| with verified complete solution
spi ultrasound physics review
when will the doppler shift be the highest
which of the following best describes the princi
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SPI Ultrasound Physics Review| 296 QUESTIONS|
WITH VERIFIED COMPLETE SOLUTION
When will the Doppler shift be the highest?
A.when the beam is parallel to the direction of flow
B.when the beam is at a 45 degree angle to flow
C.when the beam is perpendicular to the direction of flow
D. Doppler shift is unrelated to beam angle Correct Answer: A.when the beam is
parallel to the direction of flow
Which of the following best describes the principles of hemodynamics?
-The pressure difference required for blood to flow
-The pressure created in a fluid system
-A fluid's ability to resist change in shape or flow
-the study of blood circulation Correct Answer: -the study of blood circulation
The most effective way to eliminate aliasing on a color flow image is to:
-decrease the frequency output
-increase the color gain
-decrease the velocity scale
-increase the velocity scale Correct Answer: -increase the velocity scale
The increase in velocity at the center of the lumen that gradually decreases towards
the vessel wall is:
-laminar flow
-plug flow
-pulsatile flow
-parabolic flow Correct Answer: parabolic flow
While scanning the proximal common carotid artery, you adjust the color window
by making it wider. What happens to the frame rate?
-it does NOT effect the frame rate
-it increase
-it decrease
-the frame rate doubles Correct Answer: It decreases
The effect of decreased pressure in regions of high flow speeds describes the:
According to the Doppler equation, for any given velocity, the frequency shift will
increase by increasing the:
-pulse repetition frequency (PRF)
-Doppler angle
-pulse length
-transmit frequency Correct Answer: Transmit frequency
In the exercising patient, the distal arterioles are dilated. What type of flow pattern
would most likely be demonstrated on spectral Doppler within the proximal
vessels?
-Biphasic
-Triphasic
-Monophasic
-Venous Correct Answer: Monophasic
The baseline control allows the shifting of the baseline up and down to reduce the
appearance of aliasing.
True
False Correct Answer: True
The Nyquist limit is:
-the highest Doppler frequency that can be measured without the appearance of
aliasing
-caused by oversampling of the Doppler shifts
-a reflected echo with amplitude higher than the actual structure
-the lowest Doppler frequency that can be measured without the appearance of
aliasing Correct Answer: -the highest Doppler frequency that can be measured
without the appearance of aliasing
When a patient is standing upright, what is the hydrostatic pressure at the level of
the heart?
- 15 mmHg
75 mmHg
0 mmHg
100 mmHg Correct Answer: 0 mmHg
,You are performing a carotid duplex examination with the following parameters: 5
Mhz Doppler frequency, 6 kHz PRF, 4 cm depth, and 1.5 mm sample volume
length. What is the aliasing frequency?
5 MHz
6 kHz
1.5 MHz
12 kHz
3 kHz Correct Answer: 3kHz, because its 1/2 the PRF
The constant velocity in which blood travels across the vessel is:
-Parabolic Flow
Plug flow
Pulsatile velocity
spectral velocity Correct Answer: Plug flow
The Nyquist limit is equal to:
one half of the pulse repetition frequency
the operating frequency
the peak systolic velocity
the pulse repetition frequency Correct Answer: one half of the pulse repetition
frequency
While performing a Doppler study, you underestimated the measurement of the
Doppler angle of incidence. What error will result from this mistake?
Mirror imaging of the Doppler spectrum will occur.
No Doppler frequency shift will be detected.
The frequency shift will be underestimated.
Aliasing of the Doppler spectrum will occur.
The velocity estimation will be inaccurate Correct Answer: The velocity
estimation will be inaccurate
What is the hydrostatic pressure when a patient is laying down?
-30 mmHg
-50 mmHg
50 mmHg
zero Correct Answer: 0
, Which signal processing technique is used for color Doppler? It is not as accurate,
but faster, than the technique used for spectral Doppler?
autocorrelation
zero crossing
phase quadrature
Fast Fourier transform Correct Answer: autocorrelation
A flow condition in which parallel streamlines of flow are present within a vessel
is termed:
disturbed flow
turbulent flow
laminar flow
aliased flow Correct Answer: laminar flow
Which of the following will have NO effect on the measured Doppler shift?
flow velocity
tranducer frequency
propagation speed
amplitude Correct Answer: amplitude
Turbulence flow is often associated with:
cardiovascular pathology and low blood velocities
plug flow or parabolic flow
cardiovascular pathology and elevated blood velocities
reynolds number less than 2,000 Correct Answer: cardiovascular pathology and
elevated blood velocities
Confetti artifact occurs when:
when the velocity scale is decreased
when the direction of flow is perpendicular to the vessel
the color gain is set to high
the Doppler gain is set to high Correct Answer: the color gain is set to high
Click ALL that Apply
The flow rate is dependent on which of the following?
reflection from red blood cells
diameter of the vessel
transducer frequency
pressure differences
viscosity of the blood Correct Answer: pressure differences
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