Mock 2.8

15 Questions

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Questions and Answers
  • 1. 
    As the frequency matrix increases scan time _________.
    • A. 

      Increases

    • B. 

      Decreases

    • C. 

      Stays the same

    • D. 

      None of the above

  • 2. 
    If a 256 frequency encoding is selected, the system will sample the echo __________ in the presence of the frequency encoding gradient.
    • A. 

      128 times

    • B. 

      192 times

    • C. 

      256 times

    • D. 

      512 times

  • 3. 
    If a phase resolution of 256 is desired, then the pulse sequence must be repeated a minimum of __________, and with each repetition, the phase encoding gradient will be applied with a different amplitude and/or polarity.
    • A. 

      128 times

    • B. 

      192 times

    • C. 

      256 times

    • D. 

      512 times

  • 4. 
    Increasing the matrix, increases the number of phase and frequency steps and therefore __________.
    • A. 

      Increases the voxel size

    • B. 

      Decreases the voxel size

    • C. 

      Has no effect on the voxel size

    • D. 

      Increases the pixel size

  • 5. 
    Increasing the number of phase and/or frequency encodings __________.
    • A. 

      Reduces voxel volume and reduces SNR

    • B. 

      Increases voxel volume and reduces SNR

    • C. 

      Increases voxel volume and increases SNR

    • D. 

      Reduces voxel volume and increases SNR

  • 6. 
    The SNR is proportional to __________.
    • A. 

      Total sampling time2

    • B. 

      √Total sampling time

    • C. 

      Total sampling time x 2

    • D. 

      Total sampling tim

  • 7. 
    Increasing the number of phase encodings (samplings) __________.
    • A. 

      Increases samples and therefore increases truncation artifact

    • B. 

      Increases samples and therefore reduces truncation artifact

    • C. 

      Reduces samples and therefore reduces truncation artifact

    • D. 

      Reduces samples and therefore increases truncation artifact

  • 8. 
    The slice thickness is determined by the __________.
    • A. 

      Amplitude (slope) of the slice selection gradient

    • B. 

      The transmitter bandwidth

    • C. 

      Amplitude (slope) of the slice selection gradient and/or the transmitter bandwidth

    • D. 

      Neither amplitude (slope) of the slice selection gradient nor the transmitter bandwidth

  • 9. 
    In 3D or single slice acquisitions, scan time is determined by the __________.
    • A. 

      TR x #PE's x NSA

    • B. 

      TR x #PE's x NSA x # slices

    • C. 

      TR x #PE's x NSA / ETL

    • D. 

      TR x # shots x NSA

  • 10. 
    As an example, if the slice thickness is increased from 3 mm to 6 mm, the voxel volume will __________ and thus the SNR will increase by a factor of __________.
    • A. 

      Stay the same / 0

    • B. 

      Double / 2 (double)

    • C. 

      Double / 22 = 4 (quadruple)

    • D. 

      Quadruple / 4 (quadruple)

  • 11. 
    In a FSE acquisition the number of echoes produced in a single repetition is an operator selectable parameter known as the __________.
    • A. 

      "Echo Train Length" (ETL)

    • B. 

      Turbo Factor

    • C. 

      A & b

    • D. 

      None of the above

  • 12. 
    Echoes generated following higher amplitude phase encoding gradients are encoded for the __________ "lines" of k-space and echoes generated following lower amplitude phase encoding gradients are encoded for the __________ "lines" of k-space.
    • A. 

      Outer / outer

    • B. 

      Central / inner

    • C. 

      Inner / outer

    • D. 

      Outer / inner

  • 13. 
    When a long effective TE is used, it can be used in combination with a __________ however, when a short TE is used, it should be used in combination with a __________.
    • A. 

      Long ETL / short ETL

    • B. 

      Short ETL / short ETL

    • C. 

      Long ETL / long ETL

    • D. 

      Short ETL / short ETL

  • 14. 
    Motion artifacts occur along the __________ on MR images. For this reason the direction of __________ generally defaults along the short axis of the anatomy.
    • A. 

      Frequency direction / frequency encoding

    • B. 

      Phase direction / phase encoding

    • C. 

      Frequency direction / phase encoding

    • D. 

      Phase direction / frequency encoding

  • 15. 
    A 2D acquisition selectively excites a __________ of tissue while a 3D acquisition excites a __________.
    • A. 

      Slice / slice

    • B. 

      Slice / slab

    • C. 

      Proton / slab

    • D. 

      Atom / molecule