1|Page
ASMIRT- MRI ACCREDITATION EXAM TEST BANK NEWEST 2026
ACTUAL EXAM WITH COMPLETE QUESTIONS AND CORRECT
DETAILED ANSWERS (100% VERIFIED ANSWERS) |ALREADY
GRADED A+| ||PROFESSOR VERIFIED||
How can intervoxel phase dephasing be minimised? - ANSWER-
Reduction of intervoxel phase dephasing is achieved using a
technique known as Gradient Moment Nulling or flow
compensation. This has been mentioned previously. The
drawback to this technique is it results in an increase in the
minimum TE.
What is TOF MRA? - ANSWER-Time of Flight MR angiography
uses gradient echo sequences with short TR's and TE's to
saturate out the signal from stationary tissue while moving spins
flowing into an imaging slice yield high signal. Post processing in
the form of MIP's then accentuates these differences and creates
a diagnostic image.
How are 2D MRA's acquired? - ANSWER-Involves the sequential
acquisition of many thin (1-2mm) slices. These slices are then
MIP'ed to create an image of the vessels. The advantages of this
method are good background tissue suppression and the
,2|Page
technique is also sensitive to slow flow due to the thin nature of
the slices. The disadvantages are the long TE's required when
selecting thin slices leading to a loss of signal from turbulent or
complex flow
What are the key advantages of 2D TOF? - ANSWER-• it is more
sensitive to slow flow
• it provides superior blood / background contrast
• it is possible to image longer lengths of vessel since the slice by
slice approach means that this technique does not suffer from the
eventual saturation of flowing nuclei which can be a problem with
the 3D approach.
Which examinations are 2D TOFs best used for? - ANSWER-•
neck carotid arteries
• cerebral venous system (MRV)
• peripheral vessels such as femoral arteries and run offs
How are 3D TOFs acquired? - ANSWER-Also relying on the flow
related enhancement effect, 3D TOF studies excite a whole
,3|Page
volume of tissue which is then divided into thin contiguous slices
with an extra set of phase encoding steps. There is a limit to the
thickness of the slab, since eventually the fresh nuclei entering
the volume will become saturated and no longer return high signal
relative to the stationary background tissue. As with 2D TOF, a
pre-saturation slab can be used to limit the study to flow in one
direction only.
What are the key advantages of 3D TOFs? - ANSWER-• greater
SNR due to the excitation of a thick slab rather than a thin slice.
• This will allow better resolution through thinner slices, larger
matrices and smaller FOV's.
• less intra voxel dephasing will occur due to the reduced voxel
size.
• selecting a slab rather than a thin slice is less demanding on the
gradient system - this will allow shorter TE times which will also
reduce intra voxel dephasing.
Which examinations are 3D TOFs best used for? - ANSWER-3D
TOF MRA is ideally suited to anatomy such as the Circle of Willis
where high detail is required over a limited area.
, 4|Page
Mild sensory effects due to static magnetic fields include: -
ANSWER-• Vertigo
• Nausea
• Taste Sensations
Sensory effects of the static magnetic field increase or decrease
with field strength? - ANSWER-Sensory effects are related to the
strength of the magnetic field with few symptoms at 1.5T and
more appearing approaching a 4T field strength
Explain what t-wave artefact is and why it occurs - ANSWER-Any
charged particle moving through a magnetic field will have a
current induced via this interaction. As blood, a conductive fluid
flows through a magnetic field it induces an electrical biopotential.
This electrical biopotential can be seen on the ECG waveform of
patients in MRI. It is demonstrated by an increase in the T-wave
amplitude on ECG. This change in T-wave amplitude is directly
proportional to the strength of the Static Filed. It is important that
MR radiographers are aware of this as elevated T-waves are also
associated with ischemia and myocardial infarction.
ASMIRT- MRI ACCREDITATION EXAM TEST BANK NEWEST 2026
ACTUAL EXAM WITH COMPLETE QUESTIONS AND CORRECT
DETAILED ANSWERS (100% VERIFIED ANSWERS) |ALREADY
GRADED A+| ||PROFESSOR VERIFIED||
How can intervoxel phase dephasing be minimised? - ANSWER-
Reduction of intervoxel phase dephasing is achieved using a
technique known as Gradient Moment Nulling or flow
compensation. This has been mentioned previously. The
drawback to this technique is it results in an increase in the
minimum TE.
What is TOF MRA? - ANSWER-Time of Flight MR angiography
uses gradient echo sequences with short TR's and TE's to
saturate out the signal from stationary tissue while moving spins
flowing into an imaging slice yield high signal. Post processing in
the form of MIP's then accentuates these differences and creates
a diagnostic image.
How are 2D MRA's acquired? - ANSWER-Involves the sequential
acquisition of many thin (1-2mm) slices. These slices are then
MIP'ed to create an image of the vessels. The advantages of this
method are good background tissue suppression and the
,2|Page
technique is also sensitive to slow flow due to the thin nature of
the slices. The disadvantages are the long TE's required when
selecting thin slices leading to a loss of signal from turbulent or
complex flow
What are the key advantages of 2D TOF? - ANSWER-• it is more
sensitive to slow flow
• it provides superior blood / background contrast
• it is possible to image longer lengths of vessel since the slice by
slice approach means that this technique does not suffer from the
eventual saturation of flowing nuclei which can be a problem with
the 3D approach.
Which examinations are 2D TOFs best used for? - ANSWER-•
neck carotid arteries
• cerebral venous system (MRV)
• peripheral vessels such as femoral arteries and run offs
How are 3D TOFs acquired? - ANSWER-Also relying on the flow
related enhancement effect, 3D TOF studies excite a whole
,3|Page
volume of tissue which is then divided into thin contiguous slices
with an extra set of phase encoding steps. There is a limit to the
thickness of the slab, since eventually the fresh nuclei entering
the volume will become saturated and no longer return high signal
relative to the stationary background tissue. As with 2D TOF, a
pre-saturation slab can be used to limit the study to flow in one
direction only.
What are the key advantages of 3D TOFs? - ANSWER-• greater
SNR due to the excitation of a thick slab rather than a thin slice.
• This will allow better resolution through thinner slices, larger
matrices and smaller FOV's.
• less intra voxel dephasing will occur due to the reduced voxel
size.
• selecting a slab rather than a thin slice is less demanding on the
gradient system - this will allow shorter TE times which will also
reduce intra voxel dephasing.
Which examinations are 3D TOFs best used for? - ANSWER-3D
TOF MRA is ideally suited to anatomy such as the Circle of Willis
where high detail is required over a limited area.
, 4|Page
Mild sensory effects due to static magnetic fields include: -
ANSWER-• Vertigo
• Nausea
• Taste Sensations
Sensory effects of the static magnetic field increase or decrease
with field strength? - ANSWER-Sensory effects are related to the
strength of the magnetic field with few symptoms at 1.5T and
more appearing approaching a 4T field strength
Explain what t-wave artefact is and why it occurs - ANSWER-Any
charged particle moving through a magnetic field will have a
current induced via this interaction. As blood, a conductive fluid
flows through a magnetic field it induces an electrical biopotential.
This electrical biopotential can be seen on the ECG waveform of
patients in MRI. It is demonstrated by an increase in the T-wave
amplitude on ECG. This change in T-wave amplitude is directly
proportional to the strength of the Static Filed. It is important that
MR radiographers are aware of this as elevated T-waves are also
associated with ischemia and myocardial infarction.
