Physics-Artifacts

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Author:
aprilh4485
ID:
117624
Filename:
Physics-Artifacts
Updated:
2011-11-17 22:10:57
Tags:
Sonography
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Description:
Artifacts
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  1. When creating an ultrasound image, all of the following assumptions are made except:
    A. sound travels in a straight line
    B. sound travels at 1.54 km/s
    C. reflections arise only from structures in the pulse's main beam
    D. the sound beam is extremely thin
    E. all structures create reflections of equal magnitude
    E. all structures create reflections of equal magnitude
  2. Which statement regarding axial resolution is incorrect?
    A. too few reflectors appear on the image
    B. axial resolution may be reported in units of meters
    C. numerically, axial resolution equals one-half the pulse length
    D. higher quality images are associated with small numbers
    E. axial resolution artifact is related to beam diameter
    E. axial resolution artifact is related to beam diameter
    (this multiple choice question has been scrambled)
  3. An ultrasound pulse has a width of 4 mm, a length of 2 mm, and is produced by a transducer 3,000 times per second. What is the best estimate of the system's axial resolution?
    A. 4 mm
    B. 2 mm
    C. 1 mm
    D. 1500 Hz
    • C. 1 mm
    • axial resolution is equal to approx 1/2 of pulse length
  4. Which of the following statements is true about lateral resolution?
    A. it can be improved by focusing
    B. it is the same at all depths
    C. it is alos called angular, transverse, and depth resolution
    D. it is reported in units of time
    A.
    (this multiple choice question has been scrambled)
  5. All of the following artifacts results in the placement of too many echoes on the image except:
    A. shadowing
    B. reverberation
    C. mirror image
    D. grating lobes
    A. shadowing
  6. Which of the following determiens the spatial resolution of an analog display?
    A. spatial pulse length
    B. number of pixels
    C. number of lines on the display
    D. number of bits per pixel
    C. number of lines on the display
    (this multiple choice question has been scrambled)
  7. Which of the following determines the spatial resolution of a digital display?
    A. pixel density
    B. number of lines on the display
    C. spatial pulse length
    D. number of bits per pixel
    A. pixel density
    (this multiple choice question has been scrambled)
  8. Which artifact produces an image with an incorrect number of reflectors?
    A. multipath
    B. enhancement
    C. side lobes
    D. propagation speed error
    C. side lobes
    (this multiple choice question has been scrambled)
  9. True or false.
    Mirror image artifacts always appear deeper than the true anatomy.
    true
  10. Which artifact is unrelated to dimensions of an ultrasound pulse?
    A. depth resolution
    B. refraction
    C. slice thickness
    D. lateral resolution
    B. refraction
    (this multiple choice question has been scrambled)
  11. True or False.
    It is common to visualize artifacts when the dimension of the sound beam is larger than the reflector's dimension.
    true
  12. Two reflection, one true and one artifact, are displayed on an image. In the body, only one anatomic structure is present. The correct reflection and the artifact are found side by side. What is the most likely cause of this artifact?
    A. multipath
    B. grating lobe
    C. mirror image
    D. enhancement
    B. grating lobe
    (this multiple choice question has been scrambled)
  13. Two distinct reflections are observed on an image, but they actually arise form a single anatomic structure. The artifact is positioned deeper than the correct reflection. What is the most likely cause of this artifact?
    A. side lobe
    B. grating lobe
    C. refraction
    D. mirror image
    D. mirror image
    (this multiple choice question has been scrambled)
  14. Which of these artifacts does not result from multiple reflections?
    A. comet tail
    B. ring down
    C. enhancement
    D. reverberations
    C. enhancement
    (this multiple choice question has been scrambled)

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