Term
The following factors relate to what type of doppler?  range resolution  sample volume  limited maximum velocity (Nyquist)  aliasing 

Definition


Term
The following factors relate to what type of doppler?  range ambiguity  region of overlap  unlimited maximum velocity  no aliasing 

Definition


Term
The following factors relate to what type of transducer?  at least one crystal  damped PZT  low Qfactor  wide bandwidth  lower sensitivity 

Definition
Pulsed Doppler Transducer 


Term
The following factors relate to what type of transducer?  at least two crystals  undamped PZT  high Qfactor  narrow bandwidth  higher sensitivity 

Definition


Term
The following factors relate to what general type of modality?  normal incidence  higher frequency  pulsed wave only  minimum of 1 crystal 

Definition


Term
The following factors relate to what general type of modality?  0/180 degrees  lower frequency  pulsed or CW  min of 1 (pulsed) or 2 (CW) crystals 

Definition


Term
In this modality, velocity information is coded into colors and superimposed on a 2D grayscale, anatomic image 

Definition


Term
Is spectral doppler considered qualitative or quantitative? 

Definition


Term
Is color flow doppler considered qualitative or quantitative? 

Definition


Term
Since color flow doppler is based on ___ techniques, it has the same advantages (___) and disadvantage (___) 

Definition
Pulsed Wave + Range Resolution/Specificity  Aliasing 


Term
What type of velocities does color doppler report? 

Definition


Term
What does RABT stand for? 

Definition


Term
What does BART stand for? 

Definition


Term
What type of velocities does PW and CW doppler report? 

Definition


Term
In color doppler, the color represents what? 

Definition


Term
What does black represent in color doppler? 

Definition


Term
Colors above the black stripe represent blood cells moving in what direction? 

Definition


Term
Colors below the black stripe represent blood cells moving in what direction? 

Definition


Term
Flow toward the transducer is what kind of doppler shift? 

Definition


Term
Flow away from the transducer is what kind of doppler shift? 

Definition


Term
Colors closer to the black stripe represent what? 

Definition


Term
Colors farther away from the black stripe represent what? 

Definition


Term
In addition to direction and velocity, what additional information does variance mode offer? 

Definition
Laminar vs Turbulent Flow 


Term
In variance mode, what do the colors on the left side represent? 

Definition


Term
In variance mode, what do the colors on the right side represent? 

Definition


Term
In color doppler, multiple pulses are used to accurately determine blood velocities. What are these multiple pulses called? 

Definition


Term
The following advantages apply to what type of packets/ensembles?  more accurate velocity measurements  more sensitive to low flow 

Definition
Larger Packets Longer Ensemble Lengths 


Term
The following disadvantages apply to what type of packets/ensembles?  more time needed to acquire data  reduced frame rate  decreased temporal resolution 

Definition
Larger Packets Longer Ensemble Lengths 


Term
Flows detected at angles closer to 0 degrees will be ___ than those detected closer to 60 degrees 

Definition


Term
This modality only identifies the presence of a doppler shift, not speed or direction 

Definition
Power Doppler Energy Mode Color Angio 


Term
In this modality, the strength/amplitude of the reflected signal is processed, which is directly related to the number of moving blood cells 

Definition
Power Doppler Energy Mode Color Angio 


Term
What are 3 advantages of power doppler? 

Definition
1. increased sensitivity to low velocities 2. unaffected by doppler angles (unless 90 degrees exactly) 3. no aliasing 


Term
What are 3 disadvantages of power doppler? 

Definition
1. no velocity or direction information 2. lower frame rates / temporal resolution 3. susceptible to motion / flash artifacts 


Term
In addition to moving blood, very low frequency doppler shifts may be produced by ___ or ___ 

Definition
Moving Anatomy Pulsating Vessels 


Term
On spectral displays, low frequency doppler shift artifacts called what? 

Definition


Term
On color displays, low frequency doppler shift artifacts are called what? 

Definition


Term
How is clutter or ghosting eliminated? 

Definition


Term

Definition
These exclude low frequency doppler shifts around the baseline, but have no effect on higher doppler frequency shifts commonly created by blood cell motion 


Term

Definition
This is a special form of mirror image artifact that only appears with spectral doppler; while the flow pattern appears identical above and below the baseline, the true pattern in unidirectional 


Term
The following cause what type of artifact?  doppler receiver gain too high  incident angle near 90 degrees between the beam and the flow direction 

Definition


Term
This is the tool that breaks up a complex signal into the individual velocities which make up the reflected doppler signal 

Definition


Term
FFT (Fast Fourier Transform)


Definition
This doppler analysis tool is exceedingly accurate and displays all individual velocity components from the reflected signal; it is used with PW and CW doppler 


Term
Using FFT, a laminar flow will produce what in the display? 

Definition


Term
Using FFT, a turbulent flow will produce what in the display? 

Definition


Term
This doppler analysis tool is less accurate but substantially faster than FFT; it is used with color flow doppler 

Definition
Autocorrelation Correlation Function 


Term
When the spectral window is filled in, this is called what? and results from what? 

Definition
Spectral Broadening Turbulent Flow 


Term
Can a patient be so severely anemic that a doppler exam cannot be performed? 

Definition


Term
Is FFT quantitative or qualitative? 

Definition


Term
Is autocorrelation quantitative or qualitative? 

Definition


Term

Definition
This ratio is a quantitative, dopplerderived measurement of the vascular resistance of a segment of the arterial system. It requires min/max velocities 


Term

Definition
This ratio is a quantitative, dopplerderived measurement of the vascular resistance of a segment of the arterial system. It requires min/mean/max velocities 


Term
The following are advantages of what?  based on mathematical measurements  based on waveform shapes; unaffected by doppler angles 

Definition
Resistivity Index (RI) Pulsatility Index (PI) 


Term
The doppler effect is presented as a ___ when the source and the receiver are ___ 

Definition
Frequency Shift Moving relative to each other 


Term
Starting from the same point, the sound source is moving east at 12 miles/hour and the receiver is moving west at 10 miles/hour. The doppler shift is ___ 

Definition


Term
Starting from the same point, the receiver is moving west at 12 miles/hour and the source is moving west at 10 miles/hour. The doppler shift is ___ 

Definition


Term
Doppler shift produces information about ___ 

Definition


Term
At what angle between the sound beam and the direction of motion will the doppler shift be at a maximum? 

Definition


Term
At what angle between the beam and the direction of motion will the doppler shift be a minimum? 

Definition


Term
What is the difference between speed and velocity? 

Definition
Speed = magnitude Velocity = magnitude & direction 


Term
What is the current method of processing doppler signals? 

Definition
FFT for spectral doppler Autocorrelation for color doppler 


Term
What is the typical range of doppler shift found in diagnostic imaging? 

Definition
20 Hz  20 kHz (in the audible range) 


Term
The phenomenon where high velocities appear negative is called what? 

Definition


Term
The frequency at which aliasing occurs is called what? 

Definition


Term
The area of interrogation in a pulsed doppler exam is called what? 

Definition


Term
T/F: the higher the emitted frequency, the more likely a pulsed wave signal is to alias 

Definition


Term
T/F: shallower sample volumes result in more aliasing 

Definition


Term
T/F: only pulsed wave doppler exams have a sample volume 

Definition


Term
An 8 MHz transducer with a PRF of 5,000 Hz is imaging to a depth of 7 cm. What is the Nyquist frequency? A. 4 MHz B. 3.5 Hz C. 2.2 kHz D. 2.5 dB E. 5 kHz 

Definition


Term
An 8 MHz transducer with a PRF of 5,000 Hz measures a doppler shift of 7 kHz. The study is repeated with a 4 MHz transducer. What doppler shift will be measured? A. 4 MHz B. 3.5 Hz C. 4 kHz D. 3.5 dB E. 3,500 Hz 

Definition

