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Review Questions for MRI- Carolyn Roth & William Faulkner Jr. > Part C: Sequence parameters and options > Flashcards

Part C: Sequence parameters and options Flashcards

1
Q
  1. The time between excitation pulses is known as the:
    a. TI
    b. TE
    c. TR
    d. PR
A

c. TR

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2
Q
  1. In a spin echo sequence, the time between the 90° pulse and the 180° pulse is:
    a. TE
    b. TR
    c. TI
    d. 1/2 TE
A

d. 1/2 TE

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3
Q
  1. Presaturation pulses are often used to:
    a. Improve spatial resolution
    b. Reduce flow artifacts
    c. Reduce scan time
    d. Turn flowing blood bright
A

b. Reduce flow artifacts

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4
Q
  1. The presaturation pulses usually occur:
    a. Prior to the excitation pulse
    b. After the 180° pulse
    c. Between the 90° and 180° pulses
    d. Prior to the TE
A

a. Prior to the excitation pulse

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5
Q
  1. Gradient echo sequences use flip angles:
    a. Less than 90°
    b. That vary between pulse repetitions
    c. To control saturation effects
    d. To reduce SAR for larger patients
A

c. To control saturation effects

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6
Q
  1. Complete saturation is a condition where:
    a. Not enough time is given to allow the T2 decay to complete
    b. The image becomes brighter
    c. Longitudinal magnetisation is not allowed to recover between excitations
    d. Proton density effects predominate
A

c. Longitudinal magnetisation is not allowed to recover between excitations

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7
Q
  1. Increasing the TE:
    a. Increases the contrast based on T2-relxation times of the tissues
    b. Reduces the contrast based on T2-relxation times of the tissues
    c. Reduces the contrast based on T1-relxation times of the tissues
    d. a and c
A

a. Increases the contrast based on T2-relxation times of the tissues

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8
Q
  1. Reducing the TR down to or below the T1-relaxation time of the tissue:
    a. Decreases the signal-to-noise ratio (SNR) of the image
    b. Reduces the contrast based on T2 relaxation times of the tissues
    c. Increases saturation effects
    d. a and c
A

d. a and c

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9
Q
  1. Reducing the TE:
    a. Increases the contrast based on T1 relaxation times
    b. Increases the spin density contrast weighting
    c. Reduces saturation effects
    d. Reduces contrast based on T2 relaxation times
A

d. Reduces contrast based on T2 relaxation times

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10
Q
  1. As the TR increases:
    a. SNR increases up to a point
    b. SNR decreases
    c. SNR is not affected by TR
    d. TE increases
A

a. SNR increases up to a point

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11
Q
  1. As the TE increases:
    a. SNR increases
    b. SNR decreases
    c. SNR is not affected by TE
    d. TR increases
A

b. SNR decreases

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12
Q
  1. In a gradient echo sequence, reducing the flip angle while holding the TR constant reduces:
    a. T2* contrast weighting
    b. Spin density contrast weighting
    c. Saturation
    d. Scan time
A

c. Saturation

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13
Q
  1. In a 2D conventional spin echo multislice pulse sequence, scan time is given by the equation:
    a. Time x number of phase encodings (#PEs) x TR (time to repitition)
    b. TR (time to repetition) X FOV (field of view) x number of signals
    c. TR (time to repetition) x number of slices (#SI) x number of signals averaged (NSA)
    d. TR (time to repetition) x number of signals averaged (NSA) x number of phase encodings (#PEs)
A

d. TR (time to repetition) x number of signals averaged (NSA) x number of phase encodings (#PEs)

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14
Q
  1. In an inversion recovery pulse sequence, image contrast is controlled by:
    a. TR and TE only
    b. TI only
    c. T1 and TE only
    d. TR, TE and TI
A

d. TR, TE and TI

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15
Q
  1. In an inversion recovery pulse sequence, the time between the initialising 180° pulse and the 90° pulse is known as:
    a. TE
    b. TR
    c. TI
    d. T1
A

c. TI

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16
Q
  1. Another name for TI is:
    a. Alpha
    b. Theta
    c. Sigma
    d. Tau
A

d. Tau

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17
Q
  1. A short T1 inversion recovery (STIR) sequence can suppress the signal from:
    a. Fat
    b. Water
    c. A gadolinium-enhancing lesion
    d. a and c
A

d. a and c

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18
Q
  1. Decreasing the receiver bandwidth (narrow BW):
    a. Decrease the SNR
    b. Inverts the SNR
    c. Increases the SNR
    d. Has no effect on the SNR
A

c. Increases the SNR

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19
Q
  1. Decreasing the receiver bandwidth (narrow BW):
    a. Increases chemical shift artifact
    b. Inverts chemical shift artifact
    c. Reduces chemical shift artifact
    d. Has no effect on chemical shift artifact
A

a. Increases chemical shift artifact

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20
Q
  1. Decreasing the receiver bandwidth (narrow BW):
    a. Increases readout time
    b. Inverts the readout time
    c. Reduces readout time
    d. Has no effect on the readout time
A

a. Increases readout time

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21
Q
  1. Decreasing the receiver bandwidth (narrow BW):
    a. Decreases susceptibility artifact
    b. Inverts susceptibility artifact
    c. Increases susceptibility artifact
    d. Has no effect on the susceptibility artifact
A

c. Increases susceptibility artifact

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22
Q
  1. Decreasing the receiver bandwidth (narrow BW):
    a. Decreases the number of slices
    b. Inverts the number of slices
    c. Increases the number of slices
    d. Has no effect of the number of slices
A

a. Decreases the number of slices

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23
Q
  1. Increasing the receiver bandwidth (wide BW):
    a. Decreases the available ETL
    b. Inverts the available ETL
    c. Increases the available ETL
    d. Has no effect on the available ETL
A

d. Has no effect on the available ETL

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24
Q
  1. The time during which the frequency encoding gradient is on:
    a. Increases with a reduction in receiver bandwidth
    b. Decreases with a reduction in receiver bandwidth
    c. Is not affected by a reduction in receiver bandwidth
    d. Cannot be change by a reduction in receiver bandwidth
A

a. Increases with a reduction in receiver bandwidth

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25
Q
  1. In a conventional spin echo multi-echo sequence, it is possible to create multiple images, each with different amounts of:
    a. T1 weighting
    b. Phase encoding
    c. T2 weighting
    d. Spatial resolution
A

c. T2 weighting

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26
Q
  1. The SNR will increase in a 3D sequence with an increase in:
    a. FOV
    b. Number of slices
    c. TE
    d. a and b
A

d. a and b

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27
Q
  1. Between slices 2D acquisitions generally require:
    a. Wait time
    b. Gradient refocusing
    c. Gaps
    d. An inversion pulse
A

c. Gaps

28
Q
  1. Doubling the number of signals averaged (NSA) will:
    a. Decrease the SNR
    b. Increase the SNR by the square root of 2
    c. Double the SNR
    d. Not affect the SNR
A

b. Increase the SNR by the square root of 2

29
Q
  1. Increasing the number of phase encodings will produce will produce an image with:
    a. Increased voxel volume
    b. Decreased voxel volume
    c. An unchanged voxel volume
    d. Higher SNR
A

b. Decreased voxel volume

30
Q
  1. Reducing NSA will reduce the scan time and:
    a. Decrease the SNR
    b. Increase the SNR by a factor of 1.41
    c. Not affect the SNR
    d. Double the SNR
A

a. Decrease the SNR

31
Q
  1. Doubling the NSA will increase the SNR by a factor of:
    a. 2
    b. 4
    c. 1.6
    d. 1.41
A

d. 1.41

32
Q
  1. Reducing the FOV by a factor of 2 will reduce the voxel volume by a factor of:
    a. √ 2
    b. 2
    c. 8
    d. 4
A

d. 4

33
Q
  1. If a STIR sequence using a TR of 3000, a TE of 20 and a T! of 140 produces an image with dark fat and brighter water. The contrast in such an image is primarily base on:
    a. Flow
    b. T1
    c. T2
    d. Dephasing
A

b. T1

34
Q
  1. In choosing the direction of phase encoding, the technologist usually considers the direction in which the:
    a. Most signal is needed
    b. Scan time will not be affected
    c. Motion artifacts transverse the least tissue or areas of interest
    d. Resolution will not be distorted
A

c. Motion artifacts transverse the least tissue or areas of interest

35
Q
  1. A chemical or spectral fat suppression sequence will suppress the signal from fat based on the:
    a. Precessional frequency of fat
    b. Amount of fat in the target slice
    c. T2 relaxation time of fat
    d. a and c
A

a. Precessional frequency of fat

36
Q
  1. Increasing slice thickness from 5 to 10mm (by a factor of 2 i.e. 2 x thicker), the SNR:
    a. Increases by a factor of 2
    b. Increases by a factor of 4
    c. Is not affected
    d. Decreases by a factor of 2
A

a. Increases by a factor of 2

37
Q
  1. Increasing the number of phase encodings (matrix) from 128 to 256 (by a factor of 2), the SNR:
    a. Increases
    b. Inverts
    c. Is not affected
    d. Decreases
A

d. Decreases

38
Q
  1. Gradient moment nulling is most effective when correcting for motion-induced signal loss from:
    a. Pulsatile flow
    b. No flow
    c. Slow constant flow
    d. Magnetic field inhomogeneities
A

c. Slow constant flow

39
Q
  1. To rephase the signal from moving spins, gradient moment nulling techniques use a:
    a. RF pulse
    b. Gradient
    c. Series of short rapid pulses that are strategically timed
    d. Flow encoding gradient
A

b. Gradient

40
Q
  1. Using a conventional spin echo multislice sequence, the number of slices allowed hen increasing the TR:
    a. Decreases
    b. Is not affected
    c. Increases by a factor of TR/TE
    d. Doubles
A

c. Increases by a factor of TR/TE

41
Q
  1. Using a conventional spin echo multislice sequence, the number of slices allowed when increasing the TE from 20 to 40ms:
    a. Decreases
    b. Is no affected
    c. Increases by a factor of TR x TE
    d. Doubles
A

a. Decreases

42
Q
  1. Using a 3D acquisition, the number of slices allowed when increasing the TR:
    a. Decrease
    b. Is not affected
    c. Increases by a factor of TR/2
    d. Doubles
A

b. Is not affected

43
Q
  1. Using a 3D acquisition, increasing the number of slices from 64 to 128:
    a. Recues the scan time
    b. Have no effect on the scan time
    c. Increases the scan time by a factor of 1.41
    d. Doubles the scan time
A

d. Doubles the scan time

44
Q
  1. Increasing the matric in the frequency direction from 256 to 512 will:
    a. Reduce the scan time
    b. Have no effect on the scan time
    c. Increase the scan time by a factor of 256/512
    d. Double the scan time
A

b. Have no effect on the scan time

45
Q
  1. The effective TE in a fast spin echo pulse sequence determines the:
    a. Image contrast
    b. Scan time
    c. Spatial resolution
    d. Number of frequency samples
A

a. Image contrast

46
Q
  1. in a fast spin echo sequence, the central lines of k-space are associated with the:
    a. Image’s spatial resolution
    b. TR
    c. Effective TE
    d. Scan time
A

c. Effective TE

47
Q
  1. When triggering a scan from the patient’s ECG, the TR of the sequence is determined by the:
    a. Number of phase encodings selected
    b. Number of phases of the heart cycle being imaged
    c. Number of frequency encodings selected
    d. Patient’s heart rate
A

d. Patient’s heart rate

48
Q
  1. Increasing TR:
    a. Increases scan time
    b. Inverts scan time
    c. Does not affect scan time
    d. Decreases scan time
A

a. Increases scan time

49
Q
  1. Increasing TE:
    a. Increases scan time
    b. Inverts scan time
    c. Does not affect scan time
    d. Decreases scan time
A

c. Does not affect scan time

50
Q
  1. Increasing the number of slices in a 2D acquisition:
    a. Increases scan time
    b. Inverts scan time
    c. Does not affect scan time
    d. Decreases scan time
A

c. Does not affect scan time

51
Q
  1. For a given tissue with a given T1- relaxation time and TR, the flip angle, which will result in the maximum signal for that tissue, is:
    a. 90°
    b. 180°
    c. 45°
    d. the Ernst angle
A

d. the Ernst angle

52
Q
  1. Increasing the FOV:
    a. Increases scan time
    b. Inverts scan time
    c. Does not affect scan time
    d. Decreases scan time
A

c. Does not affect scan time

53
Q
  1. Increasing the phase matrix:
    a. Increases scan time
    b. Inverts scan time
    c. Does not affect scan time
    d. Decreases scan time
A

a. Increases scan time

54
Q
  1. Increasing the slice thickness:
    a. Increases scan time
    b. Inverts scan time
    c. Does not affect scan time
    d. Decreases scan time
A

c. Does not affect scan time

55
Q
  1. Increasing the NSA:
    a. Increases scan time
    b. Inverts scan time
    c. Does not affect scan time
    d. Decreases scan time
A

a. Increases scan time

56
Q
  1. Increasing the slice thickness:
    a. Increases SNR
    b. Inverts SNR
    c. Does not affect SNR
    d. Decreases SNR
A

a. Increases SNR

57
Q
  1. Increasing the matrix:
    a. Increases SNR
    b. Inverts SNR
    c. Does not affect SNR
    d. Decreases SNR
A

d. Decreases SNR

58
Q
  1. Increasing the flip angle:
    a. Inverts SNR up to the Ernst angle
    b. Inverts SNR
    c. Does not affect SNR
    d. Always decreases SNR
A

a. Inverts SNR up to the Ernst angle

59
Q
  1. Reducing the ETL:
    a. Increases scan time
    b. Inverts scan time
    c. Does not affect scan time
    d. Decreases scan time
A

a. Increases scan time

60
Q
  1. Reducing the TE:
    a. Increases SNR
    b. Inverts SNR
    c. Does not affect SNR
    d. Decreases SNR
A

a. Increases SNR

61
Q
  1. Reducing the TE yields images with:
    a. More T1 information
    b. Less T1 information
    c. More T2 information
    d. Less T2 information
A

d. Less T2 information

62
Q
  1. Increasing the TR yields images with:
    a. More T1 information
    b. Less T1 information
    c. More T2 information
    d. Less T2 information
A

b. Less T1 information

63
Q
  1. Increasing the TE yields images with:
    a. More T1 information
    b. Less T1 information
    c. More T2 information
    d. Less T2 information
A

c. More T2 information

64
Q
  1. Reducing the TR yields images with:
    a. More T1 information
    b. Less T1 information
    c. More T2 information
    d. Less T2 information
A

a. More T1 information

65
Q
  1. Reducing the flip angle yields images with:
    a. More T1 information
    b. Less T1 information
    c. More T2 information
    d. Less T2 information
A

b. Less T1 information

66
Q
  1. Increasing the flip angle yields images with:
    a. More T1 information
    b. Less T1 information
    c. More T2 information
    d. Less T2 information
A

a. More T1 information

Review Questions for MRI- Carolyn Roth & William Faulkner Jr. (18 decks)

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