Mri physics final Exam with Verified
Solutions
which pulse sequence below reduces magnetic susceptibility artifact Correct Ans-spin Echo
pulse sequence
cardiac gating is used to eliminate which artifact Correct Ans-phase miss-mapping
gradient moment nulling is most effective on Correct Ans-slow, regular flow
antispasmodic agents are used to reduce what kind of motion Correct Ans-bowel motion
when applying a preset pulse, all nuclides get flipped to the 90° transverse plane in the SAT
band. The flowing nuclei (blood) that then moves into the slice and receives the excitation pulse
are moved into Correct Ans-180° fully saturated
out of phase artifact is also called Correct Ans-chemical Mis registration
to prevent anti-aliasing along the frequency access Correct Ans-most Systems Incorporated to
filter out noise when enlarging the fov
,when using respiratory compensation, the system will perform the shallow phase encoding
gradient slopes to fill the central lines of K space when the chest wall movement is at a minimum
Correct Ans-true
what device is used in respiratory compensation Correct Ans-Bellows wrapped around the
chest
phase mismapping is caused by Correct Ans-Anatomy moving along the phase encoding
gradient during the pulse sequence
total elimination of face mapping according to the text, is impossible unless Correct Ans-you
are Imaging a cadaver
pre saturation pulses are only effective Correct Ans-if applied to tissue
this artifact is caused by undersampling by the frequency encoding gradient Correct Ans-
frequency wrap
this artifact is caused by nuclei being given the same phase outside of the fov as nuclei within the
fov Correct Ans-phase wrap
undersampling and its artifact refers to Correct Ans-the Nyquist theorem
,which remedy below is a remedy for decreasing the effects of the magnetic susceptibility artifact
Correct Ans-decreasing the TE
to prevent cross excitation, what percentage of your slice thickness should be used when you
work on a computer system that does not square off your RF pulse Correct Ans-30%
to prevent cross excitation what percentage of your slice thickness should be used when you
work on a computer system that does square off your RF pulse Correct Ans-10%
which artifact can be reduced by exciting alternate slices in a given volume Correct Ans-cross
excitation artifact
this particular remedy is used to reduce cross excitation even further than using alternate slice
excitation what is it called Correct Ans-interleaving and concatenation
one way to eliminate this artifact is to reposition the patient so they are not at a 55 degree angle
to be subscript zero Correct Ans-magic angle
which artifact below occurs only in the phase Direction Correct Ans-phase mis-mapping
which artifact below can occur in either the frequency or the phase Direction Correct Ans-
shading
, This substance has a very high positive susceptibility when exposed to a magnetic field
Correct Ans-Ferromagnetic
Gadolinium, which contains gadolinium chelates, is a member of which group Correct Ans-
Paramagnetic
What is the purpose of cryogens Correct Ans-to super cool the coils of the wire in a
superconducting magnet
Why is active shielding more commonly used than passive shielding Correct Ans--not as
heavy
-more effective
-less costly
all of the above
Current standards restrict magnetic fringe field to Correct Ans-5G
Which answer below describes how passive shielding is accomplished Correct Ans-surrounds
the magnet room with steel plates
What is the temperature of the wires of superconducting electromagnets when they exhibit zero
resistance Correct Ans-4K
Solutions
which pulse sequence below reduces magnetic susceptibility artifact Correct Ans-spin Echo
pulse sequence
cardiac gating is used to eliminate which artifact Correct Ans-phase miss-mapping
gradient moment nulling is most effective on Correct Ans-slow, regular flow
antispasmodic agents are used to reduce what kind of motion Correct Ans-bowel motion
when applying a preset pulse, all nuclides get flipped to the 90° transverse plane in the SAT
band. The flowing nuclei (blood) that then moves into the slice and receives the excitation pulse
are moved into Correct Ans-180° fully saturated
out of phase artifact is also called Correct Ans-chemical Mis registration
to prevent anti-aliasing along the frequency access Correct Ans-most Systems Incorporated to
filter out noise when enlarging the fov
,when using respiratory compensation, the system will perform the shallow phase encoding
gradient slopes to fill the central lines of K space when the chest wall movement is at a minimum
Correct Ans-true
what device is used in respiratory compensation Correct Ans-Bellows wrapped around the
chest
phase mismapping is caused by Correct Ans-Anatomy moving along the phase encoding
gradient during the pulse sequence
total elimination of face mapping according to the text, is impossible unless Correct Ans-you
are Imaging a cadaver
pre saturation pulses are only effective Correct Ans-if applied to tissue
this artifact is caused by undersampling by the frequency encoding gradient Correct Ans-
frequency wrap
this artifact is caused by nuclei being given the same phase outside of the fov as nuclei within the
fov Correct Ans-phase wrap
undersampling and its artifact refers to Correct Ans-the Nyquist theorem
,which remedy below is a remedy for decreasing the effects of the magnetic susceptibility artifact
Correct Ans-decreasing the TE
to prevent cross excitation, what percentage of your slice thickness should be used when you
work on a computer system that does not square off your RF pulse Correct Ans-30%
to prevent cross excitation what percentage of your slice thickness should be used when you
work on a computer system that does square off your RF pulse Correct Ans-10%
which artifact can be reduced by exciting alternate slices in a given volume Correct Ans-cross
excitation artifact
this particular remedy is used to reduce cross excitation even further than using alternate slice
excitation what is it called Correct Ans-interleaving and concatenation
one way to eliminate this artifact is to reposition the patient so they are not at a 55 degree angle
to be subscript zero Correct Ans-magic angle
which artifact below occurs only in the phase Direction Correct Ans-phase mis-mapping
which artifact below can occur in either the frequency or the phase Direction Correct Ans-
shading
, This substance has a very high positive susceptibility when exposed to a magnetic field
Correct Ans-Ferromagnetic
Gadolinium, which contains gadolinium chelates, is a member of which group Correct Ans-
Paramagnetic
What is the purpose of cryogens Correct Ans-to super cool the coils of the wire in a
superconducting magnet
Why is active shielding more commonly used than passive shielding Correct Ans--not as
heavy
-more effective
-less costly
all of the above
Current standards restrict magnetic fringe field to Correct Ans-5G
Which answer below describes how passive shielding is accomplished Correct Ans-surrounds
the magnet room with steel plates
What is the temperature of the wires of superconducting electromagnets when they exhibit zero
resistance Correct Ans-4K
