4357225
Pregunta 1
Pregunta
The precessional frequency of hydrogen at 1.5 telsa is
Respuesta
-
42.6MHz
-
63.86MHz
-
63.86KHz
-
21.28KHz
Pregunta 2
Pregunta
More questions regarding precessional frequency at 1.0T
Respuesta
-
1
-
2
Pregunta 3
Pregunta
Even more questions regarding precessional frequency at 0.5T
Respuesta
-
1
-
2
Pregunta 4
Pregunta
The coils used to alter the magnetic field during scanning are known as the
Respuesta
-
RF receive coils
-
RF transmit coils
-
Shim coils
-
Gradient coils
Pregunta 5
Pregunta
The precessional frequency of hydrogen nuclei that experience increased magnetic field strength due to gradient coils
Respuesta
-
Increases
-
Decreases
-
Stays the same
Pregunta 6
Pregunta
The precessional frequency of hydrogen nuclei that experience decreased magnetic field strength due to gradient coils
Respuesta
-
Increases
-
Decreases
-
Stays the same
Pregunta 7
Pregunta
There are how many pairs of gradient coils in a standard MRl system
Respuesta
-
1 pair
-
2 pairs
-
3 pairs
-
4 pairs
Pregunta 8
Pregunta
The Z gradient alters the magnetic field strength along which axis
Respuesta
-
Horizontal axis
-
Vertial axis
-
Long axis
-
Short axis
Pregunta 9
Pregunta
The Y gradient alters the magnetic field strength along which axis
Respuesta
-
Horizontal axis
-
Vertical axis
-
Long axis
-
Short axis
Pregunta 10
Pregunta
The X gradient alters the magnetic field strength along which axis
Respuesta
-
Horizontal axis
-
Vertical axis
-
Long axis
-
Short axis
Pregunta 11
Pregunta
The center of the magnet where the magnetic field strength remains unchanged even during the application of gradient magnetic fields is known as the
Respuesta
-
Pericenter
-
Isocenter
-
Monocenter
-
None of above
Pregunta 12
Pregunta
The three primary functions that gradients perform during MR scanning are
Respuesta
-
Slice selection, RF application, Frequency encoding
-
Phase encoding, Frequency encoding, RF application
-
Slice selection, Phase encoding, Frequency encoding
-
None of the above
Pregunta 13
Pregunta
During slice selection, the Z gradient is used to select slices in which plane
Respuesta
-
Coronal
-
Axial
-
Saggital
-
None of the above
Pregunta 14
Pregunta
During slice selection, the X gradient is used to select slices in which plane
Respuesta
-
Coronal
-
Axial
-
Saggital
-
None of the above
Pregunta 15
Pregunta
During slice selection, the Y gradient is used to select slices in which plane
Respuesta
-
Coronal
-
Axial
-
Saggital
-
None of the above
Pregunta 16
Pregunta
During the acquisition of sagittal images with the frequency direction S/I, phase encoding is conducted by which physical gradient
Respuesta
-
X gradient
-
Y gradient
-
Z gradient
-
None of the above
Pregunta 17
Pregunta
During the acquisition of coronal images with the frequency direction S/I, phase encoding is conducted by which physical gradient
Respuesta
-
X gradient
-
Y gradient
-
Z gradient
-
None of above
Pregunta 18
Pregunta
During the acquisition of axial images of the brain with the frequency direction A/P, phase encoding is performed by which physical gradient
Respuesta
-
X gradient
-
Y gradient
-
Z gradient
-
None of the above
Pregunta 19
Pregunta
During the acquisition of axial images of the body with the frequency direction L/R, phase encoding is performed by which physical gradient
Respuesta
-
X gradient
-
Y gradient
-
Z gradient
-
None of the above
Pregunta 20
Pregunta
During the acquisition of sagittal images with the phase direction A/P, frequency encoding is performed by which physical gradient
Respuesta
-
X gradient
-
Y gradient
-
Z gradient
-
None of the above
Pregunta 21
Pregunta
During the acquisition of coronal images with the phase direction L/R, frequency encoding is conducted by which physical gradient
Respuesta
-
X gradient
-
Y gradient
-
Z gradient
-
None of the above
Pregunta 22
Pregunta
During the acquisition of axial images of the body with the phase direction A/P, frequency encoding is performed by which physical gradient
Respuesta
-
X gradient
-
Y gradient
-
Z gradient
-
None of the above
Pregunta 23
Pregunta
During the acquisition of axial images of the brain with the phase direction L/R, frequency encoding is performed by which physical gradient
Respuesta
-
X gradient
-
Y gradient
-
Z gradient
-
None of the above
Pregunta 24
Pregunta
In MR imaging, slice thickness is determined by which factor(s)
Respuesta
-
Magnet field strength
-
Gradient slope slice select
-
Transmit bandwidth
-
Gradient slope slice select and Transmit bandwidth
Pregunta 25
Pregunta
In MRI, thin slices are achieved by applying a _______ gradient slope or a ______ bandwidth
Respuesta
-
Shallow, broad
-
Steep, narrow
-
Shallow, narrow
-
None of the above
Pregunta 26
Pregunta
In MRI, thick slices are achieved by applying a ________ gradient slope or a
_______ bandwidth
Respuesta
-
Shallow, broad
-
Steep, narrow
-
Shallow, narrow
-
None of the above
Pregunta 27
Pregunta
The range of frequencies that is sampled during frequency encoding is known as the
Respuesta
-
Receive bandwidth
-
Transmit bandwidth
-
Gradient slope
-
None the above
Pregunta 28
Pregunta
The range of frequencies that is transmitted by the RF pulse is known as the
Respuesta
-
Receive bandwidth
-
Transmit bandwidth
-
Gradient slope
-
None of the above
Pregunta 29
Pregunta
In MR imaging, the interslice gap is determined by which factor(s)
Respuesta
-
Slice selection gradient slope
-
Slice thickness
-
External magnetic field strength
-
Slice selection gradient slope & Slice thickness
Pregunta 30
Pregunta
The gradient that is turned on during the application of the 90 degree excitation pulse and the 180 degree RF pulse is known as
Respuesta
-
Slice selection gradient
-
Phase encoding gradient
-
Frequency encoding gradient
-
None of the above
Pregunta 31
Pregunta
The gradient that is turned on during signal sampling is known as the
Respuesta
-
Slice selection gradient
-
Phase encoding gradient
-
Frequency encoding gradient
-
None of the above
Pregunta 32
Pregunta
The gradient that is turned on just before the 180 degree rephasing pulse is known as the
Respuesta
-
Slice selection gradient
-
Phase encoding gradient
-
Frequency encoding gradient
-
None of the above
Pregunta 33
Pregunta
The amplitude ofthe phase and frequency encoding gradients determines the dimension of what parameter
Respuesta
-
FOV
-
TR
-
TE
-
NEX
Pregunta 34
Pregunta
The frequency encoding gradient is also known as the _______ because it is turned on during the sampling of signal
Respuesta
-
Refocusing gradient
-
Spoiler gradient
-
Readout gradient
-
Phase encoding gradient
Pregunta 35
Pregunta
The theorem that states that a frequency must be sampled at least twice in order to reproduce it reliably is known as the
Respuesta
-
Pathagarum theorem
-
Nyquist theorem
-
Larmor theorem
-
Fourier theorem
Pregunta 36
Pregunta
The rate at which signal samples are taken during frequency encoding is known as the
Respuesta
-
Readout rate
-
Frequency rate
-
Sampling rate
-
None of the above
Pregunta 37
Pregunta
During the sampling of signal, the sampling rate is directly proportional to the
Respuesta
-
Sampling time
-
Receive bandwidth
-
Transmit bandwidth
-
None of the above
Pregunta 38
Pregunta
During the sampling of the signal, the sampling time is inversely proportional to
Respuesta
-
Sampling rate
-
Transmit bandwidth
-
Receive bandwidth
-
Sampling rate & Receive bandwidth
Pregunta 39
Pregunta
The spacial location of signal according to its precessional phase is known
Respuesta
-
Slice selection
-
Phase encoding
-
Frequency encoding
-
Readout
Pregunta 40
Pregunta
The spacial location of signal according to its precessional frequency is known as
Respuesta
-
Slice selection
-
Phase encoding
-
Frequency encoding
-
Spoiling
Pregunta 41
Pregunta
The area within the array processor where spatially located information is stored is known as
Respuesta
-
Interspace
-
Array space
-
Fourier space
-
K space
Pregunta 42
Pregunta
The magnitude of the phase shifts between two points within a patient is determined by which factor
Respuesta
-
Slope of the frequency encoding gradient
-
Slope of the phase encoding gradient
-
Strength of the RF pulse
-
None of the above
Pregunta 43
Pregunta
The process that uses mathematical conversions to calculate the amplitude of individual frequencies is known as
Respuesta
-
Fast Fourier Transformation
-
Free induction decay
-
Lamor equation
-
None of the above
Pregunta 44
Pregunta
The number of times each signal is sampled with the same value of the phase encoding gradient is known as
Respuesta
-
Number of signal averages
-
Number of excitations
-
Number of signal quotients
-
All of the above
Pregunta 45
Pregunta
The higher the number of excitations that are acquired the more K space that is filled
Respuesta
-
True
-
False
Pregunta 46
Pregunta
In conventional spin echo sequences, how many phase encoding steps must be selected to fill 128 lines of K space
Respuesta
-
64
-
128
-
192
-
256
Pregunta 47
Pregunta
In conventional spin echo sequences, how many phase encoding steps must be selected to fill 256 lines of K space
Respuesta
-
64
-
128
-
192
-
256
Pregunta 48
Pregunta
Which parameter(s) effect total scan time
Respuesta
-
Repetition time
-
Number of phase encoding steps
-
Number of excitations
-
All of the above
Pregunta 49
Pregunta
During a conventional spin echo pulse sequence, each slice is selected, phase encoded, and frequency encoded once per TR
Respuesta
-
True
-
False
Pregunta 50
Pregunta
The horizontal axis of K space represents which axis of the image (with corrected answer)
Respuesta
-
Phase encoding
-
Frequency encoding
-
Slice selection
-
None of the above
Pregunta 51
Pregunta
The vertical axis of K space represents which axis of the image (with corrected answer)
Respuesta
-
Phase encoding
-
Frequency encoding
-
Slice selection
-
None of the above
Pregunta 52
Pregunta
The area of K space filled with the shallowest phase encoding slopes is known as
Respuesta
-
Central lines
-
Outer lines
-
Negative lines only
-
None of the above
Pregunta 53
Pregunta
The area of K space that is filled with the steepest phase encoding gradient slopes is known as
Respuesta
-
Central lines
-
Outer lines
-
Positive lines only
-
None of the above
Pregunta 54
Pregunta
Image data along both the phase and frequency axis with the highest signal amplitude is stored in which area of K space
Respuesta
-
Central lines
-
Outer lines
-
Positive lines only
-
None of the above
Pregunta 55
Pregunta
Image data along both the phase and frequency axis with the lowest signal amplitude is stored in which area of the K space
Respuesta
-
Central lines
-
Outer lines
-
Positive lines only
-
None of the above
Pregunta 56
Pregunta
When the phase encoding gradient is activated, steep slopes produce what type of signal amplitude
Respuesta
-
High
-
Low
-
Medium
-
None of the above
Pregunta 57
Pregunta
When the phase encoding gradient is activated, shallow slopes produce what type of signal amplitude
Respuesta
-
High
-
Low
-
Medium
-
None of the above
Pregunta 58
Pregunta
When the phase encoding gradient is activated, medium slopes produce what type of signal amplitudes
Respuesta
-
High
-
Low
-
Medium
-
None of the above
Pregunta 59
Pregunta
When the amplitude of the phase encoding gradient increases, the amount of phase shift along the gradient
Respuesta
-
Increases
-
Decreases
-
Stays the same
-
None of the above
Pregunta 60
Pregunta
When the phase encoding gradient is activated, steep slopes produce data with what type of spatial resolution
Respuesta
-
High
-
Low
-
Medium
-
None of the above
Pregunta 61
Pregunta
Image data with high spatial resolution is stored in which area of K space
Respuesta
-
Outer lines
-
Central lines
-
Negative lines only
-
Positive lines only
Pregunta 62
Pregunta
Image data with low spatial resolution is stored in which area of K space
Respuesta
-
Outer lines
-
Central lines
-
Negative lines only
-
Positive lines only
Pregunta 63
Pregunta
The process of filling K space by sampling only half of the echo and interpolating the rest is known as
Respuesta
-
Fractional echo
-
Gradient echo
-
Partial echo
-
Fractional echo & Partial echo
Pregunta 64
Pregunta
The process of filling only a percentage of K space with acquired data and filling the rest with zeros is known as
Respuesta
-
Partial saturation
-
Partial averaging
-
Partial voluming
-
Partial echo
Pregunta 65
Pregunta
Which method of image acquisition acquires all of the data from one slice before acquiring data from the next slice
Respuesta
-
Sequential
-
2D volumetric
-
3D volumetric
-
None of the above
Pregunta 66
Pregunta
Which method of image acquisition fills one line of K space for each slice in the sequence before it moves to the second line of K space
Respuesta
-
Sequential
-
2D volumetric
-
3D volumetric
-
None of the above
Pregunta 67
Pregunta
Which method ofimage acquisition acquires data from an entire volume of tissue, then uses a method called slice encoding to separate the images
Respuesta
-
Sequential
-
2D volumetric
-
3D volumetric
Pregunta 68
Pregunta
The thickness of an MRI image can be changed by which of the following methods
Respuesta
-
Altering the gradient slope
-
Changing the number of excitations
-
Altering the RF bandwidth
-
Altering the gradient slope & Altering the RF bandwidth
Pregunta 69
Pregunta
The term used to describe a volume element is known as
Respuesta
-
Pixel
-
Pixie
-
Voxel
-
Picture element
Pregunta 70
Pregunta
The number of picture elements used to make up an image is known as
Respuesta
-
Contrast
-
Matrix
-
Signal to noise
-
None of the above
Pregunta 71
Pregunta
The ability to distinguish one structure from another on an image is known as
Respuesta
-
Spatial resolution
-
Contrast to noise
-
Signal to noise
-
None of the above
Pregunta 72
Pregunta
The term used to describe a picture element is known as a
Respuesta
-
Image element
-
Pixel
-
Voxel
-
Volume element
Pregunta 73
Pregunta
The size of the area being displayed on an MR image is known as
Respuesta
-
Field of view
-
Voxel size
-
Pixel size
-
None of the above
Pregunta 74
Pregunta
The depth of a volume element is determined by what parameter
Respuesta
-
Matrix
-
NEX
-
Repetition time
-
Slice thickness
Pregunta 75
Pregunta
The height and width of a picture element is determined by what parameter(s)
Respuesta
-
Size of the FOV
-
Number of phase encoding steps
-
Number of frequency encoding steps
-
All of the above
Pregunta 76
Pregunta
A volume element that has the same height, width, and depth is known
as
Respuesta
-
Rectangular
-
Isotropic
-
Triangular
-
Anisotropic
Pregunta 77
Pregunta
A voxel that is unequal in height, width, and depth is known as
Respuesta
-
Isotropic
-
Triangular
-
Squared
-
Anisotropic
Pregunta 78
Pregunta
Three characteristics commonly used to define the quality of an MRl image are
Respuesta
-
Contrast, Resolution, Matrix
-
Resolution, Contrast, Signal to Noise
-
Signal to Noise, Excitations, Contrast
-
Resolution, Matrix, Signal to Noise
Pregunta 79
Pregunta
The difference in brightness between two regions of an image is known
Respuesta
-
Signal to noise
-
Image contrast
-
Spatial resolution
-
None of the above
Pregunta 80
Pregunta
Bright pixels on an MRI image represent what type of signal
Respuesta
-
Low
-
High
-
Weak
-
None of the above
Pregunta 81
Pregunta
The clarity with which different areas of an image are distinguished is known
as
Respuesta
-
Image contrast
-
Signal to noise
-
Spatial resolution
-
None of the above
Pregunta 82
Pregunta
The proportion of signal actually used to construct an image relative to the amount of background noise is known as
Respuesta
-
Spatial resolution
-
Signal to noise ratio
-
Image contrast
-
None of the above
Pregunta 83
Pregunta
An image with a grainy appearance usually represents an image with
Respuesta
-
High resolution
-
Low signal to noise
-
High signal to noise
-
Low resolution
Pregunta 84
Pregunta
Noise that degrades image quality in a specific location within an MRI image is known as
Respuesta
-
Inherent noise interference
-
Random noise interference
-
Discrete noise interference
-
None of the above
Pregunta 85
Pregunta
Noise that generally degrades overall quality of an MRI image is known
Respuesta
-
Inherent noise interference
-
Random noise interference
-
Discrete noise interference
-
None of the above
Pregunta 86
Pregunta
Which of the following is a parameter that directly affects signal to noise ratio
Respuesta
-
Voxel size
-
Number of excitations
-
Repetition time
-
All of the above
Pregunta 87
Pregunta
The term "Trade-off parameters" is used to describe parameters that affect each other inversely
Respuesta
-
True
-
False
Pregunta 88
Pregunta
When magnetic field strength increases, signal to noise ratio
Respuesta
-
Increases
-
Decreases
-
Stays the same
Pregunta 89
Pregunta
When voxel size decreases, signal to noise ratio
Respuesta
-
Increases
-
Decreases
-
Stays the same
Pregunta 90
Pregunta
When pixel size increases, signal to noise ratio
Respuesta
-
Increases
-
Decreases
-
Stays the same
Pregunta 91
Pregunta
When bandwidth is increased, signal to noise ratio
Respuesta
-
Increases
-
Decreases
-
Stays the same
Pregunta 92
Pregunta
When repetition time is increased, signal to noise ratio
Respuesta
-
Increases
-
Decreases
-
Stays the same
Pregunta 93
Pregunta
When echo time is increased, signal to noise ratio
Respuesta
-
Increases
-
Decreases
-
Stays the same
Pregunta 94
Pregunta
When field of view decreases, spatial resolution
Respuesta
-
Increases
-
Decreases
-
Stays the same
Pregunta 95
Pregunta
When field of view is increased, signal to noise ratio
Respuesta
-
Increases
-
Decreases
-
Stays the same
Pregunta 96
Pregunta
When the number of excitations is increased, spatial resolution
Respuesta
-
Increases
-
Decreases
-
Stays the same
Pregunta 97
Pregunta
When image matrix is increased, spatial resolution
Respuesta
-
Increases
-
Decreases
-
Stays the same
Pregunta 98
Pregunta
When slice thickness is increased, signal to noise ratio
Respuesta
-
Increases
-
Decreases
-
Stays the same
Pregunta 99
Pregunta
When slice spacing increases, signal to noise ratio
Respuesta
-
Increases
-
Decreases
-
Stays the same
Pregunta 100
Pregunta
When image matrix is decreased, spatial resolution
Respuesta
-
Increases
-
Decreases
-
Stays the same
Pregunta 101
Pregunta
When TE is decreased, the spatial resolution
Respuesta
-
Increases
-
Decreases
-
Stays the same
Pregunta 102
Pregunta
When TR is increased, acquisition time
Respuesta
-
Increases
-
Decreases
-
Stays the same
Pregunta 103
Pregunta
When the number of excitations is decreased, acquisition time
Respuesta
-
Increases
-
Decreases
-
Stays the same
Pregunta 104
Pregunta
When image matrix increases, acquisition time
Respuesta
-
Increases
-
Decreases
-
Stays the same
Pregunta 105
Pregunta
With the parameters given, which protocol gives the highest signal to noise ratio
Respuesta
-
Long TR/Short TE/High matrix
-
Short TR/Long TE/Low matrix
-
Long TR/Long TE/High matrix
-
Long TR/Short TE/Low matrix
Pregunta 106
Pregunta
With the parameters given, which protocol gives the highest spatial resolution
Respuesta
-
Thick slice/Large FOV/High matrix
-
Thin slice/Large FOV/High matrix
-
Thin slice/Small FOV/Low matrix
-
Thin slice/Small FOV/High matrix
Pregunta 107
Pregunta
With the parameters given, which protocol has the longest acquisition time
Respuesta
-
Long TR/Low NEX/Low matrix
-
Short TR/High NEX/Low matrix
-
Short TR/Low NEX/High matrix
-
Long TR/High NEX/High matrix
Pregunta 108
Pregunta
With the parameters given, which protocol gives the highest signal to noise ratio
Respuesta
-
Thick slice/Low TE/Large FOV
-
Thin slice/High TE/Small FOV
-
Thick slicelHigh TE/Small FOV
-
Thin slice/Low TE/Small FOV
Pregunta 109
Pregunta
As bandwidth increases, sampling time
Respuesta
-
Increases
-
Decreases
-
Stays the same
Pregunta 110
Pregunta
As bandwidth decreases, sampling time
Respuesta
-
Increases
-
Decreases
-
Stays the same
Pregunta 111
Pregunta
Which of the following 'logical' gradients is known as the frequency encoding gradient
Respuesta
-
X gradient
-
Y gradient
-
Z gradient
Pregunta 112
Pregunta
Which of the following 'logical' gradients is known as the phase encoding gradient
Respuesta
-
X gradient
-
Y gradient
-
Z gradient
Pregunta 113
Pregunta
Which of the following 'logical' gradients is known as the slice selection gradient
Respuesta
-
X gradient
-
Y gradient
-
Z gradient
Pregunta 114
Pregunta
In plane pixel size can be determined by which of the following methods
Respuesta
-
Dividing the FOY by the number phase and frequency steps
-
Dividing the NEX by the FOV
-
Dividing the TR by the NEX
-
Dividing the TR by the slice thickness
Pregunta 115
Pregunta
Which of the following is the formula for determining scan time for a 3D FT pulse sequence
Respuesta
-
TR x NEX x phase steps x number of slices
-
TR x NEX x phase steps
-
NEX x TR x number of slices
-
TR x phase steps x number of slices
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