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Practice Set (6) - Artifacts and Corrections

Beschreibung

Diploma MR Quiz am Practice Set (6) - Artifacts and Corrections, erstellt von S L am 30/01/2016.
S L
Quiz von S L, aktualisiert more than 1 year ago
S L
Erstellt von S L vor fast 9 Jahre
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Zusammenfassung der Ressource

Frage 1

Frage
An image artifact caused by anatomical motion along a gradient is known as what type of artifact
Antworten
  • Ringing
  • Aliasing
  • Volume averaging
  • Phase mismapping

Frage 2

Frage
Another name for phase mismapping artifact is
Antworten
  • Ringing
  • Aliasing
  • Ghosting
  • Truncation

Frage 3

Frage
An example ofphase mismapping artifact is
Antworten
  • Cardiac motion
  • Flow motion
  • Respiratory motion
  • Cardiac motion & Flow motion & Respiratory motion

Frage 4

Frage
An example of aperiodic motion is
Antworten
  • Cardiac motion
  • Flow motion
  • Respiratory motion
  • Peristalsis motion

Frage 5

Frage
Ghosting artifact on an MR image caused by the heart can be decreased by which of the following methods
Antworten
  • Decreasing bandwidth
  • Peripheral compensation
  • Cardiac gating
  • Respiratory compensation

Frage 6

Frage
Motion artifact on an MR image caused by flowing blood or CSF can be decreased by which of the following methods
Antworten
  • Respiratory compensaton
  • Patient education
  • Gradient moment nulling
  • Respiratory gating

Frage 7

Frage
Peripheral gating is a technique used to decrease what type of motion artifact
Antworten
  • CSF pulsation motion
  • Cardiac motion
  • Swallowing
  • Respiratory motion

Frage 8

Frage
A saturation pulse is a technique used to reduce what type of motion artifact
Antworten
  • Blood flow motion
  • Respiratory motion
  • Swallowing motion
  • All of the above

Frage 9

Frage
Phase mismapping artifact always occurs in which direction of the MR image
Antworten
  • Frequency direction
  • Phase direction
  • Slice selection direction
  • Readout direction

Frage 10

Frage
Phase mismapping artifact caused by respiratory motion can be decreased by which method
Antworten
  • Presaturation pulse
  • Swapping phase and frequency direction
  • Respiratory compensation
  • All of the above

Frage 11

Frage
Gradient moment nulling is most effective in reducing flow related motion in which type of flow
Antworten
  • Slow flow
  • Fast flow
  • Inplane flow
  • Slow flow and inplane flow

Frage 12

Frage
The artifact that is produced when anatomy that is outside the FOV is mapped within the FOV is known as
Antworten
  • Phase mismapping
  • Aliasing
  • Partial volume averaging
  • Magnetic susceptibility

Frage 13

Frage
Another name for aliasing artifact is
Antworten
  • Foldover artifact
  • Ringing artifact
  • Wraparound artifact
  • Foldover artifact & Wraparound artifact

Frage 14

Frage
Wraparound artifact occurs in which direction of an MR image
Antworten
  • Phase direction
  • Frequency direction
  • Slice selection direction
  • Phase direction & Frequency direction

Frage 15

Frage
Wraparound artifact caused by undersampling of frequencies in the readout direction is known as
Antworten
  • Phase wrap
  • Frequency wrap
  • Gibbs wrap
  • Truncation

Frage 16

Frage
Foldover artifact caused by undersampling of signal in the phase encoding direction is known as
Antworten
  • Phase wrap
  • Frequency wrap
  • Gibbs wrap
  • None of the above

Frage 17

Frage
Aliasing artifact in the frequency direction can be corrected by which of the following methods
Antworten
  • 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

Frage 18

Frage
Foldover artifact in the phase direction can be corrected by which of the following methods
Antworten
  • Oversampling the signal outside the FOV
  • Increasing the FOV
  • Using saturation pulses outside the FOV
  • All of the above

Frage 19

Frage
The precessional frequency of hydrogen is influenced by its chemical environment
Antworten
  • True
  • False

Frage 20

Frage
In fat, the hydrogen atom is bound with what other type of atom
Antworten
  • Oxygen
  • Nitrogen
  • Helium
  • Carbon

Frage 21

Frage
In water, the hydrogen atom is bound with what other type of atom
Antworten
  • Oxygen
  • Nitrogen
  • Helium
  • Carbon

Frage 22

Frage
The artifact that is caused due to the difference in precessional frequencies between fat and water is called
Antworten
  • Magnetic susceptibility
  • Chemical shift
  • Truncation
  • Aliasing

Frage 23

Frage
In a 1.5 tesla magnet, the difference in the precessional frequency between fat and water is
Antworten
  • 250 MHz
  • 210 MHz
  • 220 Watts
  • 220 Hz

Frage 24

Frage
In a 1.0 tesla magnet, the difference in the precessional frequency between fat and water is
Antworten
  • 130 MHz
  • 147 Hz
  • 200 Hz
  • 220 Hz

Frage 25

Frage
Chemical shift artifact occurs in which direction of the MR image
Antworten
  • Phase encoding direction
  • Frequency encoding direction
  • Slice selection direction
  • None of the above

Frage 26

Frage
In an MR image, the degree of chemical shift artifact depends upon which parameter
Antworten
  • Receive bandwidth
  • Size of the FOV
  • Magnetic field strength
  • All of the above

Frage 27

Frage
Chemical shift artifact can be minimized by which of the following methods
Antworten
  • Minimizing the FOV
  • Increasing the receive bandwidth
  • Utilizing chemical saturation
  • All of the above

Frage 28

Frage
The artifact that is caused by the phase differences between fat and water is known as
Antworten
  • Chemical shift
  • Phase wrap
  • Chemical misregistration
  • Ringing

Frage 29

Frage
Chemical misregistration artifact most commonly occurs in which direction of the MR image
Antworten
  • Phase encoding direction
  • Frequency encoding direction
  • Slice selection direction
  • None of the above

Frage 30

Frage
Chemical misregistration artifact is most likely to affect which type of pulse sequence
Antworten
  • Spin echo pulse sequences
  • Inversion recovery pulse sequences
  • Gradient echo pulse sequences
  • None of the above

Frage 31

Frage
Which imaging parameter affects the amount of chemical misregistration that will be seen on an image
Antworten
  • TR
  • TI
  • TE
  • NEX

Frage 32

Frage
At 1.5 tesla, to reduce chemical misregistration artifact, the TE should be a multiple of what time
Antworten
  • 3.1 ms
  • 4.2 ms
  • 6.6 ms
  • 7.3 ms

Frage 33

Frage
At 0.5 tesla, to reduce chemical misregistration artifact, the TE should be a multiple of what time
Antworten
  • 3.1 ms
  • 4.2 ms
  • 6.6 ms
  • 7.0 ms

Frage 34

Frage
The time that both fat and water are in phase with each other is known as
Antworten
  • Peroidicity
  • Repetition time
  • Inversion time
  • None of the above

Frage 35

Frage
Another name for truncation artifact is
Antworten
  • Foldover artifact
  • Gibbs artifact
  • Ringing artifact
  • Gibbs artifact & Ringing artifact

Frage 36

Frage
The artifact that appears as a low intensity band in areas of high intensity due to undersampling is known as
Antworten
  • Gibbs artifact
  • Truncation artifact
  • Ringing artifact
  • All of the above

Frage 37

Frage
Gibbs artifact can be decreased by ________ the number of phase encoding steps
Antworten
  • Increasing
  • Decreasing

Frage 38

Frage
Truncation artifact occurs in which direction of the MRl image
Antworten
  • Phase encoding direction
  • Frequency encoding direction
  • Slice selection direction
  • None of the above

Frage 39

Frage
Metal in the patient, in the area that is being scanned, will most likely create what type of artifact
Antworten
  • Foldover artifact
  • Chemical shift artifact
  • Truncation artifact
  • Magnetic susceptability

Frage 40

Frage
Magnetic susceptibility artifact is most prominent in what type of pulse sequence
Antworten
  • Spin echo
  • Inversion recovery
  • Gradient echo
  • None of the above

Frage 41

Frage
Magnetic susceptibility artifact can be used to help diagnose what pathology
Antworten
  • Torn meniscus
  • Herniated nucleus pulposis
  • Pituitary adenoma
  • Hemorrhage

Frage 42

Frage
An artifact that is caused by an external radio frequency leak is known as
Antworten
  • Shading artifact
  • Zipper artifact
  • Starring artifact
  • Herringbone

Frage 43

Frage
In clinical MRI, what method is used to prevent external radio frequency from affecting the MRI image
Antworten
  • Copper shielded room
  • Iron shielded magnet
  • Passive shimming
  • None of the above

Frage 44

Frage
The artifact that is produced by overlapping radio frequency pulses in adjacent slices is known as
Antworten
  • Cross excitation artifact
  • Aliasing artifact
  • Truncation artifact
  • Phase mismapping artifact

Frage 45

Frage
The artifact produced by the transfer of spin lattice energy from one slice to its adjacent slice is known as
Antworten
  • Wraparound artifact
  • Ringing artifact
  • Cross talk artifact
  • Magnetic susceptibility

Frage 46

Frage
Cross excitation artifact can be eliminated by which ofthe following methods
Antworten
  • Increasing interslice gap
  • Using a sine RF pulse
  • Interleaving
  • All of the above

Frage 47

Frage
The technique used to eliminate cross excitation artifact that acquires data in two separate acquisitions from alternating slices is known as
Antworten
  • Aliasing
  • Interleaving
  • Spin warping
  • None of the above

Frage 48

Frage
To decrease the chances of cross excitation there should be at least what percentage of interslice gap
Antworten
  • 10 %
  • 15 %
  • 30 %
  • 50 %

Frage 49

Frage
Cross excitation artifact is less likely to occur with which pulse sequence
Antworten
  • 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

Frage 50

Frage
The artifact that is produced when many structures with different signal intensities are averaged together within a pixel is known as
Antworten
  • Cross talk artifact
  • Truncation artifact
  • Partial volume averaging
  • Aliasing artifact

Frage 51

Frage
Volume averaging artifact can be reduced by which of the following methods
Antworten
  • Increasing slice thickness
  • Decreasing slice thickness
  • Increasing NEX
  • Decreasing NEX

Frage 52

Frage
The artifact that is characterized by a loss of signal intensity in one area of an image is known as
Antworten
  • Aliasing artifact
  • Ringing artifact
  • Shading artifact
  • None of the above

Frage 53

Frage
Shading artifact can be caused by what factor(s)
Antworten
  • 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

Frage 54

Frage
Data loss due to gradient instability, excessive noise, or tuning errors can cause an artifact with what type of appearance
Image:
e2867087-e083-45f1-9fb8-1c1f009f4872 (image/jpeg)
Antworten
  • Zippering
  • Shading
  • Staring
  • Herringbone

Frage 55

Frage
An artifact caused by faulty receiver attenuation settings during prescan is known as
Image:
c9d9b853-5b86-4024-8d83-47ca9b75cd19.gif (image/gif)
Antworten
  • Herringbone
  • Shading
  • Data clipping
  • Aliasing

Frage 56

Frage
Figure 6 - 1 displays an example of what type of artifact?
Image:
f0a18d51-17fa-4da1-9f2b-8188eae253c1 (image/png)
Antworten
  • Aliasing
  • Truncation
  • Foldover
  • Magnetic Susceptibility

Frage 57

Frage
Figure 6-2 displays an example of what type of artifact
Image:
65332502-a322-43a1-a4fc-74282a08e767 (image/png)
Antworten
  • Magnetic susceptibility
  • Phase wrap
  • RF zipper
  • Magnetic susceptibility & RF zipper

Frage 58

Frage
Figure 6-3 displays an example of what type of artifact
Image:
94f864e6-11ac-4cf8-a964-51c767a0aeb2 (image/png)
Antworten
  • Ringing
  • Phase wrap
  • Chemical shift
  • Cross talk

Frage 59

Frage
Figure 6-4 displays an example of what type of artifact
Image:
085699c1-4034-4e4c-9769-607d47a7ebd9 (image/png)
Antworten
  • Phase mismapping
  • Aliasing
  • Chemical shift
  • Cross excitation

Frage 60

Frage
Figure 6-5 displays an example of what type of artifact
Image:
6b0fc6a7-b561-42dd-8158-e9906ab3a879 (image/png)
Antworten
  • Truncation
  • Aliasing
  • Cross excitation
  • Chemical shift

Frage 61

Frage
Figure 6-6 displays an example of what type of artifact
Image:
cb8b8b15-bed5-4d01-86c7-5da132131837 (image/png)
Antworten
  • Aliasing
  • Truncation
  • Chemical shift
  • Phase mismapping

Frage 62

Frage
Figure 6-7 displays an example of what type of artifact
Image:
6116c789-1b47-4b9a-bcea-2695930ac295 (image/png)
Antworten
  • Aliasing
  • Truncation
  • Chemical shift
  • Phase mismapping
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