4397459
Pregunta 1
Pregunta
An image artifact caused by anatomical motion along a gradient is known as what type of artifact
Respuesta
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Ringing
-
Aliasing
-
Volume averaging
-
Phase mismapping
Pregunta 2
Pregunta
Another name for phase mismapping artifact is
Respuesta
-
Ringing
-
Aliasing
-
Ghosting
-
Truncation
Pregunta 3
Pregunta
An example ofphase mismapping artifact is
Respuesta
-
Cardiac motion
-
Flow motion
-
Respiratory motion
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Cardiac motion & Flow motion & Respiratory motion
Pregunta 4
Pregunta
An example of aperiodic motion is
Respuesta
-
Cardiac motion
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Flow motion
-
Respiratory motion
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Peristalsis motion
Pregunta 5
Pregunta
Ghosting artifact on an MR image caused by the heart can be decreased by which of the following methods
Respuesta
-
Decreasing bandwidth
-
Peripheral compensation
-
Cardiac gating
-
Respiratory compensation
Pregunta 6
Pregunta
Motion artifact on an MR image caused by flowing blood or CSF can be decreased by which of the following methods
Respuesta
-
Respiratory compensaton
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Patient education
-
Gradient moment nulling
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Respiratory gating
Pregunta 7
Pregunta
Peripheral gating is a technique used to decrease what type of motion artifact
Respuesta
-
CSF pulsation motion
-
Cardiac motion
-
Swallowing
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Respiratory motion
Pregunta 8
Pregunta
A saturation pulse is a technique used to reduce what type of motion artifact
Respuesta
-
Blood flow motion
-
Respiratory motion
-
Swallowing motion
-
All of the above
Pregunta 9
Pregunta
Phase mismapping artifact always occurs in which direction of the MR image
Respuesta
-
Frequency direction
-
Phase direction
-
Slice selection direction
-
Readout direction
Pregunta 10
Pregunta
Phase mismapping artifact caused by respiratory motion can be decreased by which method
Respuesta
-
Presaturation pulse
-
Swapping phase and frequency direction
-
Respiratory compensation
-
All of the above
Pregunta 11
Pregunta
Gradient moment nulling is most effective in reducing flow related motion in which type of flow
Respuesta
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Slow flow
-
Fast flow
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Inplane flow
-
Slow flow and inplane flow
Pregunta 12
Pregunta
The artifact that is produced when anatomy that is outside the FOV is mapped within the FOV is known as
Respuesta
-
Phase mismapping
-
Aliasing
-
Partial volume averaging
-
Magnetic susceptibility
Pregunta 13
Pregunta
Another name for aliasing artifact is
Respuesta
-
Foldover artifact
-
Ringing artifact
-
Wraparound artifact
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Foldover artifact & Wraparound artifact
Pregunta 14
Pregunta
Wraparound artifact occurs in which direction of an MR image
Respuesta
-
Phase direction
-
Frequency direction
-
Slice selection direction
-
Phase direction & Frequency direction
Pregunta 15
Pregunta
Wraparound artifact caused by undersampling of frequencies in the readout direction is known as
Respuesta
-
Phase wrap
-
Frequency wrap
-
Gibbs wrap
-
Truncation
Pregunta 16
Pregunta
Foldover artifact caused by undersampling of signal in the phase encoding direction is known as
Respuesta
-
Phase wrap
-
Frequency wrap
-
Gibbs wrap
-
None of the above
Pregunta 17
Pregunta
Aliasing artifact in the frequency direction can be corrected by which of the following methods
Respuesta
-
Decreasing the FOV
-
Increasing the matrix
-
Filtering the frequencies outside the FOV in the phase direction
-
Filtering the frequencies outside the FOV in the frequency direction
Pregunta 18
Pregunta
Foldover artifact in the phase direction can be corrected by which of the following methods
Respuesta
-
Oversampling the signal outside the FOV
-
Increasing the FOV
-
Using saturation pulses outside the FOV
-
All of the above
Pregunta 19
Pregunta
The precessional frequency of hydrogen is influenced by its chemical environment
Respuesta
-
True
-
False
Pregunta 20
Pregunta
In fat, the hydrogen atom is bound with what other type of atom
Respuesta
-
Oxygen
-
Nitrogen
-
Helium
-
Carbon
Pregunta 21
Pregunta
In water, the hydrogen atom is bound with what other type of atom
Respuesta
-
Oxygen
-
Nitrogen
-
Helium
-
Carbon
Pregunta 22
Pregunta
The artifact that is caused due to the difference in precessional frequencies between fat and water is called
Respuesta
-
Magnetic susceptibility
-
Chemical shift
-
Truncation
-
Aliasing
Pregunta 23
Pregunta
In a 1.5 tesla magnet, the difference in the precessional frequency between fat and water is
Respuesta
-
250 MHz
-
210 MHz
-
220 Watts
-
220 Hz
Pregunta 24
Pregunta
In a 1.0 tesla magnet, the difference in the precessional frequency between fat and water is
Respuesta
-
130 MHz
-
147 Hz
-
200 Hz
-
220 Hz
Pregunta 25
Pregunta
Chemical shift artifact occurs in which direction of the MR image
Respuesta
-
Phase encoding direction
-
Frequency encoding direction
-
Slice selection direction
-
None of the above
Pregunta 26
Pregunta
In an MR image, the degree of chemical shift artifact depends upon which parameter
Respuesta
-
Receive bandwidth
-
Size of the FOV
-
Magnetic field strength
-
All of the above
Pregunta 27
Pregunta
Chemical shift artifact can be minimized by which of the following methods
Respuesta
-
Minimizing the FOV
-
Increasing the receive bandwidth
-
Utilizing chemical saturation
-
All of the above
Pregunta 28
Pregunta
The artifact that is caused by the phase differences between fat and water is known as
Respuesta
-
Chemical shift
-
Phase wrap
-
Chemical misregistration
-
Ringing
Pregunta 29
Pregunta
Chemical misregistration artifact most commonly occurs in which direction of the MR image
Respuesta
-
Phase encoding direction
-
Frequency encoding direction
-
Slice selection direction
-
None of the above
Pregunta 30
Pregunta
Chemical misregistration artifact is most likely to affect which type of pulse sequence
Respuesta
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Spin echo pulse sequences
-
Inversion recovery pulse sequences
-
Gradient echo pulse sequences
-
None of the above
Pregunta 31
Pregunta
Which imaging parameter affects the amount of chemical misregistration that will be seen on an image
Respuesta
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TR
-
TI
-
TE
-
NEX
Pregunta 32
Pregunta
At 1.5 tesla, to reduce chemical misregistration artifact, the TE should be a multiple of what time
Respuesta
-
3.1 ms
-
4.2 ms
-
6.6 ms
-
7.3 ms
Pregunta 33
Pregunta
At 0.5 tesla, to reduce chemical misregistration artifact, the TE should be a multiple of what time
Respuesta
-
3.1 ms
-
4.2 ms
-
6.6 ms
-
7.0 ms
Pregunta 34
Pregunta
The time that both fat and water are in phase with each other is known as
Respuesta
-
Peroidicity
-
Repetition time
-
Inversion time
-
None of the above
Pregunta 35
Pregunta
Another name for truncation artifact is
Respuesta
-
Foldover artifact
-
Gibbs artifact
-
Ringing artifact
-
Gibbs artifact & Ringing artifact
Pregunta 36
Pregunta
The artifact that appears as a low intensity band in areas of high intensity due to undersampling is known as
Respuesta
-
Gibbs artifact
-
Truncation artifact
-
Ringing artifact
-
All of the above
Pregunta 37
Pregunta
Gibbs artifact can be decreased by ________ the number of phase encoding steps
Respuesta
-
Increasing
-
Decreasing
Pregunta 38
Pregunta
Truncation artifact occurs in which direction of the MRl image
Respuesta
-
Phase encoding direction
-
Frequency encoding direction
-
Slice selection direction
-
None of the above
Pregunta 39
Pregunta
Metal in the patient, in the area that is being scanned, will most likely create what type of artifact
Respuesta
-
Foldover artifact
-
Chemical shift artifact
-
Truncation artifact
-
Magnetic susceptability
Pregunta 40
Pregunta
Magnetic susceptibility artifact is most prominent in what type of pulse sequence
Respuesta
-
Spin echo
-
Inversion recovery
-
Gradient echo
-
None of the above
Pregunta 41
Pregunta
Magnetic susceptibility artifact can be used to help diagnose what pathology
Respuesta
-
Torn meniscus
-
Herniated nucleus pulposis
-
Pituitary adenoma
-
Hemorrhage
Pregunta 42
Pregunta
An artifact that is caused by an external radio frequency leak is known as
Respuesta
-
Shading artifact
-
Zipper artifact
-
Starring artifact
-
Herringbone
Pregunta 43
Pregunta
In clinical MRI, what method is used to prevent external radio frequency from affecting the MRI image
Respuesta
-
Copper shielded room
-
Iron shielded magnet
-
Passive shimming
-
None of the above
Pregunta 44
Pregunta
The artifact that is produced by overlapping radio frequency pulses in adjacent slices is known as
Respuesta
-
Cross excitation artifact
-
Aliasing artifact
-
Truncation artifact
-
Phase mismapping artifact
Pregunta 45
Pregunta
The artifact produced by the transfer of spin lattice energy from one slice
to its adjacent slice is known as
Respuesta
-
Wraparound artifact
-
Ringing artifact
-
Cross talk artifact
-
Magnetic susceptibility
Pregunta 46
Pregunta
Cross excitation artifact can be eliminated by which ofthe following methods
Respuesta
-
Increasing interslice gap
-
Using a sine RF pulse
-
Interleaving
-
All of the above
Pregunta 47
Pregunta
The technique used to eliminate cross excitation artifact that acquires data in two separate acquisitions from alternating slices is known as
Respuesta
-
Aliasing
-
Interleaving
-
Spin warping
-
None of the above
Pregunta 48
Pregunta
To decrease the chances of cross excitation there should be at least what percentage of interslice gap
Respuesta
-
10 %
-
15 %
-
30 %
-
50 %
Pregunta 49
Pregunta
Cross excitation artifact is less likely to occur with which pulse sequence
Respuesta
-
Spin echo, 90 degree flip angle, 10% interslice gap
-
Spin echo, 90 degree flip angle, 50% interslice gap
-
Gradient echo, 15 degree flip angle, 30% interslice gap
-
Dual echo, 90 degree flip angle, 25% interslice gap
Pregunta 50
Pregunta
The artifact that is produced when many structures with different signal intensities are averaged together within a pixel is known as
Respuesta
-
Cross talk artifact
-
Truncation artifact
-
Partial volume averaging
-
Aliasing artifact
Pregunta 51
Pregunta
Volume averaging artifact can be reduced by which of the following methods
Respuesta
-
Increasing slice thickness
-
Decreasing slice thickness
-
Increasing NEX
-
Decreasing NEX
Pregunta 52
Pregunta
The artifact that is characterized by a loss of signal intensity in one area of an image is known as
Respuesta
-
Aliasing artifact
-
Ringing artifact
-
Shading artifact
-
None of the above
Pregunta 53
Pregunta
Shading artifact can be caused by what factor(s)
Respuesta
-
Inhomogeneity of the external magnetic field
-
Undersampling of phase encoding steps
-
Inhomogeneity of the RF pulse
-
Inhomogeneity of the external magnetic field & Inhomogeneity of the RF pulse
Pregunta 54
Pregunta
Data loss due to gradient instability, excessive noise, or tuning errors can cause an artifact with what type of appearance
Respuesta
-
Zippering
-
Shading
-
Staring
-
Herringbone
Pregunta 55
Pregunta
An artifact caused by faulty receiver attenuation settings during prescan is known as
Respuesta
-
Herringbone
-
Shading
-
Data clipping
-
Aliasing
Pregunta 56
Pregunta
Figure 6 - 1 displays an example of what type of artifact?
Respuesta
-
Aliasing
-
Truncation
-
Foldover
-
Magnetic Susceptibility
Pregunta 57
Pregunta
Figure 6-2 displays an example of what type of artifact
Respuesta
-
Magnetic susceptibility
-
Phase wrap
-
RF zipper
-
Magnetic susceptibility & RF zipper
Pregunta 58
Pregunta
Figure 6-3 displays an example of what type of artifact
Respuesta
-
Ringing
-
Phase wrap
-
Chemical shift
-
Cross talk
Pregunta 59
Pregunta
Figure 6-4 displays an example of what type of artifact
Respuesta
-
Phase mismapping
-
Aliasing
-
Chemical shift
-
Cross excitation
Pregunta 60
Pregunta
Figure 6-5 displays an example of what type of artifact
Respuesta
-
Truncation
-
Aliasing
-
Cross excitation
-
Chemical shift
Pregunta 61
Pregunta
Figure 6-6 displays an example of what type of artifact
Respuesta
-
Aliasing
-
Truncation
-
Chemical shift
-
Phase mismapping
Pregunta 62
Pregunta
Figure 6-7 displays an example of what type of artifact
Respuesta
-
Aliasing
-
Truncation
-
Chemical shift
-
Phase mismapping
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