Test
Practice Set (6) - Artifacts and Corrections
Preguntas del test (62)
1An image artifact caused by anatomical motion along a gradient is known as what type of artifact
- ARinging
- BAliasing
- CVolume averaging
- DPhase mismapping
2Another name for phase mismapping artifact is
- ARinging
- BAliasing
- CGhosting
- DTruncation
3An example ofphase mismapping artifact is
- ACardiac motion
- BFlow motion
- CRespiratory motion
- DCardiac motion & Flow motion & Respiratory motion
4An example of aperiodic motion is
- ACardiac motion
- BFlow motion
- CRespiratory motion
- DPeristalsis motion
5Ghosting artifact on an MR image caused by the heart can be decreased by which of the following methods
- ADecreasing bandwidth
- BPeripheral compensation
- CCardiac gating
- DRespiratory compensation
6Motion artifact on an MR image caused by flowing blood or CSF can be decreased by which of the following methods
- ARespiratory compensaton
- BPatient education
- CGradient moment nulling
- DRespiratory gating
7Peripheral gating is a technique used to decrease what type of motion artifact
- ACSF pulsation motion
- BCardiac motion
- CSwallowing
- DRespiratory motion
8A saturation pulse is a technique used to reduce what type of motion artifact
- ABlood flow motion
- BRespiratory motion
- CSwallowing motion
- DAll of the above
9Phase mismapping artifact always occurs in which direction of the MR image
- AFrequency direction
- BPhase direction
- CSlice selection direction
- DReadout direction
10Phase mismapping artifact caused by respiratory motion can be decreased by which method
- APresaturation pulse
- BSwapping phase and frequency direction
- CRespiratory compensation
- DAll of the above
11Gradient moment nulling is most effective in reducing flow related motion in which type of flow
- ASlow flow
- BFast flow
- CInplane flow
- DSlow flow and inplane flow
12The artifact that is produced when anatomy that is outside the FOV is mapped within the FOV is known as
- APhase mismapping
- BAliasing
- CPartial volume averaging
- DMagnetic susceptibility
13Another name for aliasing artifact is
- AFoldover artifact
- BRinging artifact
- CWraparound artifact
- DFoldover artifact & Wraparound artifact
14Wraparound artifact occurs in which direction of an MR image
- APhase direction
- BFrequency direction
- CSlice selection direction
- DPhase direction & Frequency direction
15Wraparound artifact caused by undersampling of frequencies in the readout direction is known as
- APhase wrap
- BFrequency wrap
- CGibbs wrap
- DTruncation
16Foldover artifact caused by undersampling of signal in the phase encoding direction is known as
- APhase wrap
- BFrequency wrap
- CGibbs wrap
- DNone of the above
17Aliasing artifact in the frequency direction can be corrected by which of the following methods
- ADecreasing the FOV
- BIncreasing the matrix
- CFiltering the frequencies outside the FOV in the phase direction
- DFiltering the frequencies outside the FOV in the frequency direction
18Foldover artifact in the phase direction can be corrected by which of the following methods
- AOversampling the signal outside the FOV
- BIncreasing the FOV
- CUsing saturation pulses outside the FOV
- DAll of the above
19The precessional frequency of hydrogen is influenced by its chemical environment
- ATrue
- BFalse
20In fat, the hydrogen atom is bound with what other type of atom
- AOxygen
- BNitrogen
- CHelium
- DCarbon
21In water, the hydrogen atom is bound with what other type of atom
- AOxygen
- BNitrogen
- CHelium
- DCarbon
22The artifact that is caused due to the difference in precessional frequencies between fat and water is called
- AMagnetic susceptibility
- BChemical shift
- CTruncation
- DAliasing
23In a 1.5 tesla magnet, the difference in the precessional frequency between fat and water is
- A250 MHz
- B210 MHz
- C220 Watts
- D220 Hz
24In a 1.0 tesla magnet, the difference in the precessional frequency between fat and water is
- A130 MHz
- B147 Hz
- C200 Hz
- D220 Hz
25Chemical shift artifact occurs in which direction of the MR image
- APhase encoding direction
- BFrequency encoding direction
- CSlice selection direction
- DNone of the above
26In an MR image, the degree of chemical shift artifact depends upon which parameter
- AReceive bandwidth
- BSize of the FOV
- CMagnetic field strength
- DAll of the above
27Chemical shift artifact can be minimized by which of the following methods
- AMinimizing the FOV
- BIncreasing the receive bandwidth
- CUtilizing chemical saturation
- DAll of the above
28The artifact that is caused by the phase differences between fat and water is known as
- AChemical shift
- BPhase wrap
- CChemical misregistration
- DRinging
29Chemical misregistration artifact most commonly occurs in which direction of the MR image
- APhase encoding direction
- BFrequency encoding direction
- CSlice selection direction
- DNone of the above
30Chemical misregistration artifact is most likely to affect which type of pulse sequence
- ASpin echo pulse sequences
- BInversion recovery pulse sequences
- CGradient echo pulse sequences
- DNone of the above
31Which imaging parameter affects the amount of chemical misregistration that will be seen on an image
- ATR
- BTI
- CTE
- DNEX
32At 1.5 tesla, to reduce chemical misregistration artifact, the TE should be a multiple of what time
- A3.1 ms
- B4.2 ms
- C6.6 ms
- D7.3 ms
33At 0.5 tesla, to reduce chemical misregistration artifact, the TE should be a multiple of what time
- A3.1 ms
- B4.2 ms
- C6.6 ms
- D7.0 ms
34The time that both fat and water are in phase with each other is known as
- APeroidicity
- BRepetition time
- CInversion time
- DNone of the above
35Another name for truncation artifact is
- AFoldover artifact
- BGibbs artifact
- CRinging artifact
- DGibbs artifact & Ringing artifact
36The artifact that appears as a low intensity band in areas of high intensity due to undersampling is known as
- AGibbs artifact
- BTruncation artifact
- CRinging artifact
- DAll of the above
37Gibbs artifact can be decreased by ________ the number of phase encoding steps
- AIncreasing
- BDecreasing
38Truncation artifact occurs in which direction of the MRl image
- APhase encoding direction
- BFrequency encoding direction
- CSlice selection direction
- DNone of the above
39Metal in the patient, in the area that is being scanned, will most likely create what type of artifact
- AFoldover artifact
- BChemical shift artifact
- CTruncation artifact
- DMagnetic susceptability
40Magnetic susceptibility artifact is most prominent in what type of pulse sequence
- ASpin echo
- BInversion recovery
- CGradient echo
- DNone of the above
41Magnetic susceptibility artifact can be used to help diagnose what pathology
- ATorn meniscus
- BHerniated nucleus pulposis
- CPituitary adenoma
- DHemorrhage
42An artifact that is caused by an external radio frequency leak is known as
- AShading artifact
- BZipper artifact
- CStarring artifact
- DHerringbone
43In clinical MRI, what method is used to prevent external radio frequency from affecting the MRI image
- ACopper shielded room
- BIron shielded magnet
- CPassive shimming
- DNone of the above
44The artifact that is produced by overlapping radio frequency pulses in adjacent slices is known as
- ACross excitation artifact
- BAliasing artifact
- CTruncation artifact
- DPhase mismapping artifact
45The artifact produced by the transfer of spin lattice energy from one slice
to its adjacent slice is known as- AWraparound artifact
- BRinging artifact
- CCross talk artifact
- DMagnetic susceptibility
46Cross excitation artifact can be eliminated by which ofthe following methods
- AIncreasing interslice gap
- BUsing a sine RF pulse
- CInterleaving
- DAll of the above
47The technique used to eliminate cross excitation artifact that acquires data in two separate acquisitions from alternating slices is known as
- AAliasing
- BInterleaving
- CSpin warping
- DNone of the above
48To decrease the chances of cross excitation there should be at least what percentage of interslice gap
- A10 %
- B15 %
- C30 %
- D50 %
49Cross excitation artifact is less likely to occur with which pulse sequence
- ASpin echo, 90 degree flip angle, 10% interslice gap
- BSpin echo, 90 degree flip angle, 50% interslice gap
- CGradient echo, 15 degree flip angle, 30% interslice gap
- DDual echo, 90 degree flip angle, 25% interslice gap
50The artifact that is produced when many structures with different signal intensities are averaged together within a pixel is known as
- ACross talk artifact
- BTruncation artifact
- CPartial volume averaging
- DAliasing artifact
51Volume averaging artifact can be reduced by which of the following methods
- AIncreasing slice thickness
- BDecreasing slice thickness
- CIncreasing NEX
- DDecreasing NEX
52The artifact that is characterized by a loss of signal intensity in one area of an image is known as
- AAliasing artifact
- BRinging artifact
- CShading artifact
- DNone of the above
53Shading artifact can be caused by what factor(s)
- AInhomogeneity of the external magnetic field
- BUndersampling of phase encoding steps
- CInhomogeneity of the RF pulse
- DInhomogeneity of the external magnetic field & Inhomogeneity of the RF pulse
54Data loss due to gradient instability, excessive noise, or tuning errors can cause an artifact with what type of appearance
- AZippering
- BShading
- CStaring
- DHerringbone
55An artifact caused by faulty receiver attenuation settings during prescan is known as
- AHerringbone
- BShading
- CData clipping
- DAliasing
56Figure 6 - 1 displays an example of what type of artifact?
- AAliasing
- BTruncation
- CFoldover
- DMagnetic Susceptibility
57Figure 6-2 displays an example of what type of artifact
- AMagnetic susceptibility
- BPhase wrap
- CRF zipper
- DMagnetic susceptibility & RF zipper
58Figure 6-3 displays an example of what type of artifact
- ARinging
- BPhase wrap
- CChemical shift
- DCross talk
59Figure 6-4 displays an example of what type of artifact
- APhase mismapping
- BAliasing
- CChemical shift
- DCross excitation
60Figure 6-5 displays an example of what type of artifact
- ATruncation
- BAliasing
- CCross excitation
- DChemical shift
61Figure 6-6 displays an example of what type of artifact
- AAliasing
- BTruncation
- CChemical shift
- DPhase mismapping
62Figure 6-7 displays an example of what type of artifact
- AAliasing
- BTruncation
- CChemical shift
- DPhase mismapping
Información
- Descripción
- Diploma MR Test sobre Practice Set (6) - Artifacts and Corrections, creado por S L el 30/01/2016.
- Autor
- S L
- Idioma
- English
- Visitas
- 100
- Historial
- Creado el 30 ene 2016 · actualizado el 12 abr 2016
- Etiquetas
- Valoración
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