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64 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Identify the artifact that would have occurred if small bands of high signal extends from the near wall of the gallbladder |
Comet tail |
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Which artifact is commonly observed in the bladder |
Reverberation which artifact does not cause a special missed registration in the image |
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Which artifact does not cause a spatial misregistration in the image |
Attenuation |
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A feature that appears on the image but does not correspond to an anatomical structure is called |
Artifact |
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The artifact that interferes with the ability to detect a low contrast object is known as |
Acoustic speckle |
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The artifact that occurs from the thickness of the scanned tissue volume perpendicular to the scan plane is called |
Elevational resolution |
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Multiple equally spaced reflections on the image decreasing in intensity is called |
Reverberation |
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A type of reverberation artifact due to metal within the body is called |
Comet tail |
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Acoustic energy emitted in a direction different than the main axis of the sound beam is called |
Side lobes |
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If the speed of sound is greater than 1540 m/s the echo will be placed |
Too close to the transducer |
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The absence or reduced intensity of echo information distal to a reflector is called |
Shadowing |
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An example of an artifact helpful in diagnoses is |
Shadowing |
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When creating an ultrasound image all of the following assumptions are made except |
All structures create reflections of equal magnitude |
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Which statement regarding Axel resolution is incorrect |
Axial resolution artifact is related to beam diameter |
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And ultrasound pulse has a width of 4 mm a length of 2 mm and is produced by a transducer 3000 times per second. What is the best estimate of the systems axial resolution? |
1mm |
2÷2 |
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Which of the following statements is true about lateral resolution |
It can be improved by focusing |
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All of the following artifacts result in the placement of too many echoes on the image except |
Shadowing |
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Which of the following determines the spatial resolution of a display |
Number of lines on the display |
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Which of the following determines the spatial resolution of a digital display |
Pixel density |
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Which artifact produces an image with an incorrect number of reflectors |
Side lobes |
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True or false: mirror image artifact always appear deeper than the true anatomy |
True |
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True or false: it is common to visualize artifacts when the dimension of the sound beam is larger than the reflectors dimension |
True |
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Two reflections, one true and one artifact, Are displayed on the ultrasound image. In the body, only one anatomic structures present. The correct reflection and artifact are side-by-side. What is the most likely cause of this artifact |
Grating lobe |
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Two distinct reflections are observed on an image, but they actually arise from a single anatomic structure. The artifact is positioned deeper than the correct reflection. Which is the most likely cause of this artifact |
Mirror image |
Mirror mirror on the wall |
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Which of these artifacts does not result from multiple reflections |
Enhancement |
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To avoid the range ambiguity artifact |
The pulser of an instrument automatically reduces the PRF for deeper imaging |
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Reverberation results in added reflectors being imaged with equal |
Separation |
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And reverberation, subsequent reflections are |
Weaker than the previous ones |
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Enhancement is caused by |
Weakly attenuating structure |
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Propagation speed errors result in improper |
Axial position of a reflector on the display |
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Which artifact should be suspected if one observes twin gestational sacs when scanning through the rectus abdominis muscle |
Refraction |
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When a pulse is emitted before all echoes from the previous pulse have been received, which artifact |
Range ambiguity |
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Acoustic artifacts include |
Images of reflectors in an inappropriate position, images of reflectors with improper shape, images of reflectors with incorrect brightness, images that do not correspond to anatomical structures |
Four answers |
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Ultrasound systems are designed to automatically |
Display all reflections on a line corresponding to the main axis of the sound beam, regardless of refraction |
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What’s the cause of acoustic speckle |
Interference of tiny acoustic wavelets |
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Artifact results from an ultrasound beam having a finite and measurable 3-D profile |
Slice thickness artifact |
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How does slice thickness artifact commonly express itself |
Fill in of cystic structures |
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What artifact results in improper side-by-side positioning of reflectors |
Refraction |
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What assumption is violated when A reflected soundwaves is processed |
Sound travels in a straight line |
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Six distinct equally spaced reflectors appear on an image at ever increasing depth what type of artifact is this |
Reverberation |
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Which situation will commonly produce reverberation artifact |
Two strong reflectors that lie along the main axis of the beam |
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Which process causes mirror image artifact |
Reflection |
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Where is a mirror image artifact located |
Always deeper on the image than in the body |
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What are the characteristics of a medium that produce comet tail artifact |
Strong reflectors, closely spaced, high propagation speed |
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What is a comet tail artifacts fundamental mechanism of formation |
Reflection |
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Diagnostic imaging, how does multipath artifact affect the image |
Mild image degradation |
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What causes enhancement artifact |
Unexpectedly low acoustic attenuation |
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What causes side lobe artifact |
Acoustic energy radiating in a direction other than the beams main axis |
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Sidelobe artifact usually results in all of the following except |
Reflectors not appearing on an image |
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Grading lobes are most common with which type of transducer technology |
Linear arrays |
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Grading lobes are produced by the same mechanism as which other artifact |
Side lobes |
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Which technique of linear array transducer design has virtually eliminated the appearance of grading lobe artifact on modern ultrasound system |
Subdicing |
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Where are shadowing artifact commonly seen on an acoustic scan |
Deeper than a structure with high attenuation |
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How is shadowing artifact expressed |
Reflectors being absent on the image |
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Which of these produce shadowing |
Attenuation |
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When enhancement occurs, where does it appear on the image |
Deeper than a weak attenuator |
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What is the likely cause of ring down artifact |
Reverberation below gas-air bubble |
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Which type of artifact causes a reflection to be placed an incorrect depth |
Range ambiguity |
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If an ultrasound pulse travels through a large mass in the body at a speed of 1.2 mm/us what happens to the position of all echoes produced from reflectors shallower than the mass |
They are likely to be placed at the correct depth |
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If an ultrasound pulse travels through a large mass in the body at a speed of 1.2 mm/us what happens to the position of all echoes produced from reflectors deeper than the mass |
They are placed in too deep of a location on the image |
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Two small cysts positioned perpendicular to the main axis of a sound beam are 2.4 mm apart. What determines whether they appear as two distinct images on the systems display |
The beam width |
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Axial resolution artifacts are due to which of the following |
Pulse length |
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Which artifact is created by sound moving through a medium with a propagation speed less than soft tissue |
Vertical misregistration |
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When enhancement occurs where does it appear on the image |
Deeper than a weak attenuator |
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