SPI 2 EXAM 4 UPDATED ACTUAL
QUESTIONS AND CORRECT ANSWERS
Question:
1. doppler effect
Answer:
change in frequency and wavelength caused by motion of a sound source, receiver, or reflector
Question:
2. doppler shift
Answer:
-difference between the frequency of the received sound and the frequency of the emitted sound
Question:
3. what does doppler shift determine
Answer:
direction and velocity
Question:
4. doppler shift equation (what are the units)
Answer:
fD= fR-fT fD is in kHz fR and fT are in MHz
Question:
5. Doppler equation (what does is measure and calculate)
Answer:
fD= 2/c x v x fT x cos(theta)
- measures shift and calculates velocity
Question:
6. color doppler
Answer:
- presents anatomic info in grayscale and rapidly detects shifts of blood flow at several locations along
each scan line
- the color box is superimposed over the 2D image demonstrating depth information
Question:
7. color doppler affect on FR
Answer:
- several images (frames) are displayed each second which allows for real time color doppler imaging
- 2 images stitched together -> decreased FR
Question:
8. autocorrelation
, Answer:
- only used in color doppler
- mathematical process that rapidly determines mean (average), variance (spread around the mean),
sign (+/- towards or away)
Question:
9. color doppler allows the control of
Answer:
PRF/Scale (sets the limit at teh color bar extremes_
- decreasedscale allows for display of slow flow or smaller shifts
- increased scale shows high velocity without aliasing
Question:
10. Nyquist limit equation
Answer:
PRF/2
Question:
11. color doppler limitations
Answer:
- angle dependent
- low FR
- cannot use multiple foci
- displays the mean, not the peak
- give qualitative info about velocity (slow vs fast) but not quantitative info (measure)
Question:
12. color doppler advantages
Answer:
- allows us to demonstrate flow abnormalities (turbulence, high velocity, and areas of no flow)
Question:
13. power doppler
Answer:
encodes STRENGTH (power and intensity) of the shifts
Question:
14. (power doppler) power of the shifts is determined by
Answer:
concentration of moving scatterers
Question:
15. PD display there is a ________ presentation of flow info at the expense of _________, _______,
and _______
Answer:
- uniform presentation at the expense of: flow direction, speed, and character info
Question:
16. power doppler advantages
QUESTIONS AND CORRECT ANSWERS
Question:
1. doppler effect
Answer:
change in frequency and wavelength caused by motion of a sound source, receiver, or reflector
Question:
2. doppler shift
Answer:
-difference between the frequency of the received sound and the frequency of the emitted sound
Question:
3. what does doppler shift determine
Answer:
direction and velocity
Question:
4. doppler shift equation (what are the units)
Answer:
fD= fR-fT fD is in kHz fR and fT are in MHz
Question:
5. Doppler equation (what does is measure and calculate)
Answer:
fD= 2/c x v x fT x cos(theta)
- measures shift and calculates velocity
Question:
6. color doppler
Answer:
- presents anatomic info in grayscale and rapidly detects shifts of blood flow at several locations along
each scan line
- the color box is superimposed over the 2D image demonstrating depth information
Question:
7. color doppler affect on FR
Answer:
- several images (frames) are displayed each second which allows for real time color doppler imaging
- 2 images stitched together -> decreased FR
Question:
8. autocorrelation
, Answer:
- only used in color doppler
- mathematical process that rapidly determines mean (average), variance (spread around the mean),
sign (+/- towards or away)
Question:
9. color doppler allows the control of
Answer:
PRF/Scale (sets the limit at teh color bar extremes_
- decreasedscale allows for display of slow flow or smaller shifts
- increased scale shows high velocity without aliasing
Question:
10. Nyquist limit equation
Answer:
PRF/2
Question:
11. color doppler limitations
Answer:
- angle dependent
- low FR
- cannot use multiple foci
- displays the mean, not the peak
- give qualitative info about velocity (slow vs fast) but not quantitative info (measure)
Question:
12. color doppler advantages
Answer:
- allows us to demonstrate flow abnormalities (turbulence, high velocity, and areas of no flow)
Question:
13. power doppler
Answer:
encodes STRENGTH (power and intensity) of the shifts
Question:
14. (power doppler) power of the shifts is determined by
Answer:
concentration of moving scatterers
Question:
15. PD display there is a ________ presentation of flow info at the expense of _________, _______,
and _______
Answer:
- uniform presentation at the expense of: flow direction, speed, and character info
Question:
16. power doppler advantages
