ARRT FINAL EXAM ACTUAL EXAM TEST BANK 400
QUESTIONS AND CORRECT DETAILED ANSWERS
(VERIFIED ANSWERS) |ALREADY GRADED A+
3D gradient echo axial views can be used in cervical spine imaging to provide -
ANSWER: Thin, contiguous sections of the spine, the ability to reformat into any
other imaging plane, retrospectively, the ability to get either T1, spin density or T2*
information by changing parameters.
In complete spine imaging, to rule out metastatic lesions of the spinal cord, contrast
enhancement can be used with T1 weighted images because - ANSWER: metastatic
lesions enhance and normal cord does not
Due to the differences in frequencies across the magnetic field we - ANSWER: use
gradients, use sat bands, . use different coils
To avoid the "magic angle" (an artifactual brightness seen in the medial segment of
the posterior horn of the lateral meniscus when short TEs are used) artifact when
imaging the knee, - ANSWER: use a longer TE, reposition the knee, orient the
affected anatomy to another angle
To best visualize the anterior cruciate ligament on knee MR - ANSWER: externally
rotate the leg about 15
When using MRA to evaluate intracranial vascularity, flow within smaller vessels can
best be demonstrated by - ANSWER: 3D time of flight MRA or 3D phase contrast
MRA
To produce the echo, a gradient echo pulse sequence uses - ANSWER: a gradient
magnetic field only
The rate of dephasing due to inhomogeneities is called - ANSWER: T2 inhomogeneity
If the TR of a gradient echo pulse sequence is considerably less than the T2 (and
T2*), the condition that will exist is known as - ANSWER: steady state
The gradient that is on during the production of the echo is the __________
encoding gradient - ANSWER: frequency
The gradient that is on longest is the __________ encoding gradient - ANSWER:
frequency
The four phases of a spin echo pulse sequence, in correct order, are - ANSWER:
Excitation, encoding, refocusing, readout.
, Using an NSA of 3, if a phase resolution of 192 is desired, then the TR must be
repeated - ANSWER: 576 times
In a fast spin echo sequence, the effective TE is the echo that is performed with the -
ANSWER: Low amplitude phase encoding gradient.
In a 2D multiecho pulse sequence, ETL = 8, scan time is given by the equation TR x -
ANSWER: Number of signals averaged x number of phase encodings / the number of
echoes.
When using MRA to evaluate extracranial vascular flow, such as that within common
carotid arteries, a recommended technique is - ANSWER: 2D time of flight MRA
When using bright blood MRA to evaluate peripheral vascular flow, such as that
within the arteries of the legs, saturation pulses are - ANSWER: placed inferior to the
acquired slices
In a 3D acquisition, the slices are produced by - ANSWER: A phase encoding gradient
applied in the slice direction. Acquired by volume imaging.
To create a projection image in MRA, the technique MOST commonly employed is -
ANSWER: 19. maximum intensity pixel
If a given conventional spin echo pulse sequence takes 12 minutes to acquire, a
multiecho sequence, using a 6 echo train, with all factors that affect scan time
remaining the same, will take ________________ to acquire the same images -
ANSWER: 2 minutes
Gadolinium chelates are - ANSWER: Paramagnetic.
Acquiring half the phase views of k space and then calculating the data for the other
half is a technique known as - ANSWER: partial Fourier
The MRA sequence that is more sensitive to slow flow is - ANSWER: 2D time of flight
A major advantage of MRA over conventional angiography is that - ANSWER: 2D time
of flight
The removal of signal from vessels in an MRA sequence is achieved by - ANSWER:
spatial presaturation
In a spin echo sequence, flowing blood is normally seen as a signal void because -
ANSWER: the 90o pulse and the 180o pulse are both slice selective
In a time of flight sequence, the tissue is hypointense relative to flowing blood
because of - ANSWER: saturation effects
QUESTIONS AND CORRECT DETAILED ANSWERS
(VERIFIED ANSWERS) |ALREADY GRADED A+
3D gradient echo axial views can be used in cervical spine imaging to provide -
ANSWER: Thin, contiguous sections of the spine, the ability to reformat into any
other imaging plane, retrospectively, the ability to get either T1, spin density or T2*
information by changing parameters.
In complete spine imaging, to rule out metastatic lesions of the spinal cord, contrast
enhancement can be used with T1 weighted images because - ANSWER: metastatic
lesions enhance and normal cord does not
Due to the differences in frequencies across the magnetic field we - ANSWER: use
gradients, use sat bands, . use different coils
To avoid the "magic angle" (an artifactual brightness seen in the medial segment of
the posterior horn of the lateral meniscus when short TEs are used) artifact when
imaging the knee, - ANSWER: use a longer TE, reposition the knee, orient the
affected anatomy to another angle
To best visualize the anterior cruciate ligament on knee MR - ANSWER: externally
rotate the leg about 15
When using MRA to evaluate intracranial vascularity, flow within smaller vessels can
best be demonstrated by - ANSWER: 3D time of flight MRA or 3D phase contrast
MRA
To produce the echo, a gradient echo pulse sequence uses - ANSWER: a gradient
magnetic field only
The rate of dephasing due to inhomogeneities is called - ANSWER: T2 inhomogeneity
If the TR of a gradient echo pulse sequence is considerably less than the T2 (and
T2*), the condition that will exist is known as - ANSWER: steady state
The gradient that is on during the production of the echo is the __________
encoding gradient - ANSWER: frequency
The gradient that is on longest is the __________ encoding gradient - ANSWER:
frequency
The four phases of a spin echo pulse sequence, in correct order, are - ANSWER:
Excitation, encoding, refocusing, readout.
, Using an NSA of 3, if a phase resolution of 192 is desired, then the TR must be
repeated - ANSWER: 576 times
In a fast spin echo sequence, the effective TE is the echo that is performed with the -
ANSWER: Low amplitude phase encoding gradient.
In a 2D multiecho pulse sequence, ETL = 8, scan time is given by the equation TR x -
ANSWER: Number of signals averaged x number of phase encodings / the number of
echoes.
When using MRA to evaluate extracranial vascular flow, such as that within common
carotid arteries, a recommended technique is - ANSWER: 2D time of flight MRA
When using bright blood MRA to evaluate peripheral vascular flow, such as that
within the arteries of the legs, saturation pulses are - ANSWER: placed inferior to the
acquired slices
In a 3D acquisition, the slices are produced by - ANSWER: A phase encoding gradient
applied in the slice direction. Acquired by volume imaging.
To create a projection image in MRA, the technique MOST commonly employed is -
ANSWER: 19. maximum intensity pixel
If a given conventional spin echo pulse sequence takes 12 minutes to acquire, a
multiecho sequence, using a 6 echo train, with all factors that affect scan time
remaining the same, will take ________________ to acquire the same images -
ANSWER: 2 minutes
Gadolinium chelates are - ANSWER: Paramagnetic.
Acquiring half the phase views of k space and then calculating the data for the other
half is a technique known as - ANSWER: partial Fourier
The MRA sequence that is more sensitive to slow flow is - ANSWER: 2D time of flight
A major advantage of MRA over conventional angiography is that - ANSWER: 2D time
of flight
The removal of signal from vessels in an MRA sequence is achieved by - ANSWER:
spatial presaturation
In a spin echo sequence, flowing blood is normally seen as a signal void because -
ANSWER: the 90o pulse and the 180o pulse are both slice selective
In a time of flight sequence, the tissue is hypointense relative to flowing blood
because of - ANSWER: saturation effects
