Physics Review Flashcards
Operating or transducer frequency is choose based on scanning depth and depends on what 2 factors
1) scan type
b) body habitus
If you increase the frequency what happens to the axial resolution and penetration
Better axial resolution
poor penetration
If you decrease the frequency what happens to the penetration and axial resolution
Deeper penetration
Degrade axial resolution
What type of transducer and frequency would you use for a peripheral duplex exam
7-12 MHz linear array
What type of transducer and frequency would you use for an abdominal duplex exam
2-6 MHz curved linear array
What type of transducer and frequency would you use for an intraoperative exam
12-15 MHz array
What type of imaging resolution depends on transducer frequency
a) axial
b) lateral
c) temporal
a) axial
- increase frequency to improve visualization of vessel wall thickness or plaque
What type of imaging resolution depends on beam width
a) axial
b) lateral
c) temporal
b) Lateral
Increasing the number of focal zones, increasing line density, and decreasing sector angle all help improve what imaging resolution
a) axial
b) lateral
c) temporal
b) lateral
What type of imaging resolution depends on frame rate
a) axial
b) lateral
c) temporal
c) temporal
Decreasing line density/ sector angle, decreasing the number of focal zones, and decreasing the color box all improve which imaging resolution
a) axial
b) lateral
c) temporal
c) temporal
What are 2 other names for reverberation
1) comet tail
b) ring down
Several bright false echoes deep to real reflectors describe what artifact
a) reverberation
b) posterior shadowing
c) posterior enhancement
d) mirror image
a) reverberation
Microcalcifications, gas bubbles, syringe needles, and catheters are examples of what artifact
a) reverberation
b) posterior shadowing
c) posterior enhancement
d) mirror image
a) reverberation
What artifact has severe attenuation with a dark band deep to highly reflecting objects
a) reverberation
b) posterior shadowing
c) posterior enhancement
d) mirror image
b) posterior shadowing
Bony structures and calcified plaque are examples of what imaging artifact
a) reverberation
b) posterior shadowing
c) posterior enhancement
d) mirror image
b) posterior shadowing
Lack of attenuation from fluid-filled structures describes what imaging artifact
a) reverberation
b) posterior shadowing
c) posterior enhancement
d) mirror image
c) posterior enhancement
Cysts and hematomas are examples of what imaging artifact
a) reverberation
b) posterior shadowing
c) posterior enhancecment
d) mirror image
c) posterior enhancement
Copy of echoes deep to renal anatomy/specular reflectors describes what imaging artifact
a) reverberation
b) posterior shadowing
c) posterior enhancement
d) mirror image
d) mirror image
The liver/diaphragm and larger arteries are examples of what imaging artifact
a) reverberation
b) posterior shadowing
c) posterior enhancement
d) mirror image
d) mirror image
Moving towards the sound source the received frequency would be
a) higher
b) lower
a) higher
Moving away from the sound source the received frequency would be
a) higher
b) lower
b) lower
The difference between the reflected and transmitted frequencies is called
Frequency shift
What is another name for frequency shift
Doppler shift
If the received frequency is greater than the transmitted this would be considered a
a) positive shift
b) negative shift
a) positive shift
If the received frequency is less than the transmitted this would considered a
a) positive shift
b) negative shift
b) negative shift
How are velocity and shift related
Direct
How are frequency and shift related
Direct
How are angle and shift related
Inverse
If the angle is closer to 90 degrees what happens to the doppler shift
a) decrease
b) no shift
c) greater shift
a) decrease
If the angle is 90 degrees or perpendicular what happens to the shift
a) decreases
b) no shift
c) greater shift
b) no shift
What happens to the shift when the angle is 0 degrees or parallel or 180 degrees
a) decreases
b) no shift
c) greater shift
c) greater shift
Is color considered qualitative or quantitative
qualitative
______ only displays direction and averaged velocities
Color
Slow flow is considered
a) low scale
b) high scale
a) low scale
Fast flow is considered
a) low scale
b) high scale
b) high scale
Closer to parallel= _____ doppler shift and brighter color
a) higher
b) lower
a) higher
Perpendicular = ________ doppler shift and will be black
No
The negative color is always going to be _______ the side the box is steered
a) towards
b) away
a) towards
The positive color is always going to be ________ from the the side the box is being steered
a) towards
b) away
b) away
This evaluates flow over on small area called sample volume
Pulsed doppler
Whats another name for sample volume
Range gating
Is pulsed doppler considered to be qualitative or quantitative
Quantitatitve
What breaks down the signal into separate components according to velocity and time
Spectral analysis
What are 2 other names for power doppler
1) energy doppler
2) amplitude doppler
What only detects and displays the presence of flow and there is NO direction info
Power Doppler
This type of doppler is very sensitive to slow flow
Power doppler
Unable to determine depth or location is called
Range ambiguous
What is only used as a flow detector or to measure severely elevated velocities
Continuous wave doppler
What type of doppler can not choose a location
Continuous wave doppler
Which of the folllowing is a disadvantage of a continuous wave doppler unit
a) range ambiguity
b) inaccurate velocity calculation
c) risk of aliasing
d) qualitative assessment only
a) range ambiguity
CW doppler does not allow for range location. Meaning we can’t tell or choose the location of the doppler signal
What pathology is most likely to produce posterior enhancement
a) cellulitis
b) dense plaque
c) chronic DVT
d) bakers cyst
d) baker cyst
- fluid filled structures will produce posterior enhancement
Which of the following will produce no doppler shift
a) decreasing the doppler angle
b) 90 degrees incidence
c) 0 degree incidence
d) lowering the wall filter
b) 90 degree incidence
There is no doppler shift at 90 degrees or perpendicular incidence
What diagnostic applications can power doppler be useful?
a) valvular incompetence
b) confirm near total occlusion
c) hemodialysis access grafts
d) subclavian steal
b) confirm near total occlusion
Which change will correct aliasing
a) decrease scale
b) increase transducer frequency
c) increase wall filter
d) decrease transducer frequency
d) decrease transducer frequency
-The only things that will help eliminate aliasing are
1) increase PRF/velocity scale
2) lower baseline
3) decrease transducer frequency
4) increase doppler angle
Which artifact will mimic an aortic dissection
a) Propagational speed error artifact
b) Grating lobe artifact
c) Side lobe artifact
d) Mirror imaging arifact
c) Side lobe artifact
