Module 6 Review Flashcards
Which of the following is an example of an object imaged at the correct distance but is lateral to its proper location?
- Refraction
- Propagation speed error
- Side lobes
- A and C
- All of the above
- Refraction and side lobes
What assumption accounts for the artifact imaged at the correct distance but lateral to its proper location?
- Sound travels in a straight line
- Echoes originate from points along the main beam axis
What artifacts can cause objects to be displayed in improper location or incorrect sizes, or both?
- Propagation
- Refraction
Which statement is correct speed error artifacts?
- If the propagation speed is greater than 1.54 mm/usec, the display will place the reflector closer to the transducer
- If the propagation speed is greater than 1.54 mm/usec, The display will place the reflector further from the transducer
- If the propagation speed is less than 1.54 mm/usec, the display will place the reflector closer to the transducer
- If the propagation speed is less than 1.54 mm/usec, the display will place the reflector further from the transducer
E. A and D
F. B and C
E) A and D
What category of artifact does edge shadow belong to?
Refraction
When does edge shadowing occur?
When structures are curved and larger than the beam width
Focal enhancements is due to what?
Increased intensity at the focal zone
Focal enhancement is defined as what?
False brightening of the image at the focal zone
Enhancement is caused by what?
A weakly attenuating structure
An example of enhancement can be seen beneath what?
A cyst and a bile in the gallblader
Mirror image artifacts are a variant of reverberation, T/F?
True
When a strong Specular reflector is located in the scan plane, which of the following artifacts is likely to occur?
Mirror image
Which of the following statements relates to comet tail artifact?
- Associates with the presence of a collection of gas bubbles
- Beams that propagate from a single element in directions different from the primary beam
- Reverberations that appear as equally spaced discrete echoes
- Appearance of false debris in an echo free space
- Reverberations that appear as equally spaced discrete echoes
From the following examples, which would NOT cause a comet tail artifact?
- Biopsy needle
- Gas bubble s
- Intrauterine contraceptive device
- Thin layers of calcium
- Gas bubbles
Grating lobes are caused by areas of energy angled outside the main beam. Which of the following is a solution to resolve this artifact?
- Decreasing spacing between elements
- Increasing spacing between elements
- Subdicing
- Apodization
- A and C and D
- B and C and D
- A and C and D
Grating lobes occur in ________ transducers and are seen as linear echogenic bands or sheets in ______ structures
Array, anechoic
Beam width perpendicular to the scan plane causes what type of artifact?
Section thickness
The fact that a beam, as it passes through tissue has some non-zero width perpendicular to the scan plane describes the results of __________ artifact
Section thickness
Which modes can range ambiguity occur with?
1. 2D
2. Pulsed doppler
3. Colour follow doppler
4. A and C
5. All of the above
- All of the above
Which of the following may cause a range ambiguity artifact?
- Use of an increased doppler angle
- Increased PRF
- Pulsed emitted before the previously received pulse
- B and C
- All of the above
- B and C
Which of the following best describes refraction
- A Back and forth reflection of part or all of a sound beam between two strong reflectors
- A change in the direction of propagation of sound wave transmitted across a interface where the speed of sound varies
- A manifestation of increased echo signal amplitudes
- A loss of echo signals from distal structures due to attenuation
- A change in the direction of propagation of a sound wave transmitted across a interface where the speed of sound varies
Which of the following will NOT produce a shadow?
- Calcified plaque
- Air in the biliary duct
- True cyst
- Gallstone
- C and D
True cyst
Which of the following best describes shadowing?
- Absorption
- Attenuation
- Penetration
- Propagation
- Reverberation
Attenuation
If axial resolution is 2 mm and multiple parallel structures are located 4 mm apart, what will happen to the appearance of the structures?
Structures will be visualized at the their real distance and size
If axial resolution is 4 mm and multiple parallel structures are located 2 mm apart, what will happen to the appearance of the structures?
Structures may merge and appear as a single object
Ring down artifacts are most likely caused by what?
The presence of collection of gas bubbles
In reverberation, subsequent reflections are _________ than previous ones.
Weaker
The multiple reflections, in reverberation, are placed beneath the real reflector at separation intervals _________ the separation between the transducer and the real reflector.
Equal
What impact does a smaller lateral resolution have on the image?
Image enhancement
What will improve lateral resolution?
Reducing the beam diameter
How will the reflectors deep to a structure that has a speed of sound greater than 1540 m/s appear?
Closer to the probe
How would one correct for artifacts related to lateral resolutions?
Scan in the near zone
Which of the following is the best way to reduce the clutter in a colour image?
Increase the filter
Which of the following is the result of an odd angled strong reflector?
- Mirror image
- Edge shadow
- Refractive duplication
- Refractive mail position
- Mirror image
Which of the following could be used to correct mirror imaging in a spectral trace?
- Move the baseline
- Turn down the 2D gain
- Turn down the spectral gain
- Change the operating frequency
Turn down the spectral gain
Which of the following artifacts is the results of gas bubbles?
- Comet tail
- Ring down
- Grating lobes
- Reverberation
Ring down
Which of the following may occur when the spectral gain is set to high?
- Aliasing
- Decreased EDV
- Decreased resistive index
- Over estimation of the PSV
Over estimation of the PSV
Which of the following artifacts is due to the assumption that sound travels at 1540 m/s?
Speed error
Which of the following has the biggest impact in reducing reverberation?
- Harmonics
- Reduce gain
- Reduce TGC
- Increase the persistence
Harmonics
Which of the following artifact can be useful in diagnosis a calculus?
- Shadowing
- Enhancement
- Reverberation
- None of the above
Shadowing