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ASMIRT MRI ACCREDITATION EXAM VERSION 1 LATEST 2026-2027 ACTUAL
EXAM WITH COMPLETE QUESTIONS AND CORRECT DETAILED ANSWERS
(100% VERIFIED ANSWERS) |ALREADY GRADED A+| ||PROFESSOR VERIFIED||
||BRANDNEW!!!||
In 2D MRI, which plane will give rise to a sagittal slice, a coronal
slice and an axial slice? - ANSWER-For 2D MRI, a slice-select
gradient is applied over the top of the main magnetic field and
perpendicular to the desired plane: • X axis for a sagittal slice • Y
axis for a coronal slice • Z axis for an axial slice
How can the desired slice be excited in an MRI sequence? -
ANSWER-The precessional frequency will vary along this axis
due to the application of the gradient and an RF pulse can be
applied with a bandwidth of frequencies so that only protons in the
desired slice are excited.
How can one decrease slice thickness? - ANSWER-The slice
thickness can be decreased by:
• using a steeper gradient
• using a narrower bandwidth RF pulse .
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What does the frequency encoding gradient do and what will it's
strength depend on? - ANSWER-The frequency encoding
gradient is switched on as the echo is received and will produce a
frequency shift dependent on position along this axis. This will
allow the signal to be resolved in one direction. The strength of
the frequency encoding gradient required will depend on:
• the field of view
• the receiver bandwidth - i.e. the range of frequencies used to
span the FOV
What does the phase encoding gradient do? - ANSWER-The
phase encoding gradient is pulsed on briefly after the excitation
pulse to produce a phase shift between adjacent rows of pixels.
This is repeated as many times as there are pixels in the phase
encoding direction. With each step, the strength of the gradient is
varied slightly from a maximum positive value though zero to a
maximum negative value. This will produce a different phase shift
between pixel rows for each step. The gradient strength required
for these maximum steps will depend on: • the field of view • the
number of pixels in the phase encoding direction
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To maximize spatial resolution, what needs to occurs between the
steepest positive and negative steps? - ANSWER-To maximise
spatial resolution, the steepest positive and negative steps will
need to create a 180 degree phase shift between adjacent
columns since this will produce the maximum possible phase
separation.
The strength of the phase encoding gradient depends on -
ANSWER-The gradient strength required for these maximum
steps will depend on:
• the field of view
• the number of pixels in the phase encoding direction
What is sampling? - ANSWER-The echo is sampled and digitised
in the presence of a frequency encoding (or read-out) gradient.
This is known as analog to digital conversion. The results are
stored in an array known as k-space. (
What is ADC, reference sampling rate and Nyquist theorem? -
ANSWER-Converting the analog waveform into a digital signal
requires us to sample the waveform at multiple different points. In
, 4|Page
order to represent this waveform accurately we must sample the
waveform at a high enough rate. This is known as the sampling
rate. The sampling rate used in MRI is known as the Nyquist
frequency and relates to The Nyquist Theorem. The Nyquist
Theorem is important to MRI and it dictates that any signal must
be sampled at least twice per cycle to represent it accurately
What is the sampling time, the sampling rate and receiver
bandwidth? - ANSWER-• The sampling time is the duration of the
gradient while 256 or 512 frequencies are sampled. (eg. 8 msec)
• The sampling rate is the rate at which these samples are taken.
• The receiver bandwidth is the range of frequencies sampled
during read-out (eg 16 kHz
What does reducing bandwidth do in terms of trade-offs? -
ANSWER-Reducing the bandwidth will:
• increase sampling time
• increase SNR
• increase echo spacing for FSE scans and increase blurring
• increase chemical shift and susceptibility artefact.
ASMIRT MRI ACCREDITATION EXAM VERSION 1 LATEST 2026-2027 ACTUAL
EXAM WITH COMPLETE QUESTIONS AND CORRECT DETAILED ANSWERS
(100% VERIFIED ANSWERS) |ALREADY GRADED A+| ||PROFESSOR VERIFIED||
||BRANDNEW!!!||
In 2D MRI, which plane will give rise to a sagittal slice, a coronal
slice and an axial slice? - ANSWER-For 2D MRI, a slice-select
gradient is applied over the top of the main magnetic field and
perpendicular to the desired plane: • X axis for a sagittal slice • Y
axis for a coronal slice • Z axis for an axial slice
How can the desired slice be excited in an MRI sequence? -
ANSWER-The precessional frequency will vary along this axis
due to the application of the gradient and an RF pulse can be
applied with a bandwidth of frequencies so that only protons in the
desired slice are excited.
How can one decrease slice thickness? - ANSWER-The slice
thickness can be decreased by:
• using a steeper gradient
• using a narrower bandwidth RF pulse .
,2|Page
What does the frequency encoding gradient do and what will it's
strength depend on? - ANSWER-The frequency encoding
gradient is switched on as the echo is received and will produce a
frequency shift dependent on position along this axis. This will
allow the signal to be resolved in one direction. The strength of
the frequency encoding gradient required will depend on:
• the field of view
• the receiver bandwidth - i.e. the range of frequencies used to
span the FOV
What does the phase encoding gradient do? - ANSWER-The
phase encoding gradient is pulsed on briefly after the excitation
pulse to produce a phase shift between adjacent rows of pixels.
This is repeated as many times as there are pixels in the phase
encoding direction. With each step, the strength of the gradient is
varied slightly from a maximum positive value though zero to a
maximum negative value. This will produce a different phase shift
between pixel rows for each step. The gradient strength required
for these maximum steps will depend on: • the field of view • the
number of pixels in the phase encoding direction
,3|Page
To maximize spatial resolution, what needs to occurs between the
steepest positive and negative steps? - ANSWER-To maximise
spatial resolution, the steepest positive and negative steps will
need to create a 180 degree phase shift between adjacent
columns since this will produce the maximum possible phase
separation.
The strength of the phase encoding gradient depends on -
ANSWER-The gradient strength required for these maximum
steps will depend on:
• the field of view
• the number of pixels in the phase encoding direction
What is sampling? - ANSWER-The echo is sampled and digitised
in the presence of a frequency encoding (or read-out) gradient.
This is known as analog to digital conversion. The results are
stored in an array known as k-space. (
What is ADC, reference sampling rate and Nyquist theorem? -
ANSWER-Converting the analog waveform into a digital signal
requires us to sample the waveform at multiple different points. In
, 4|Page
order to represent this waveform accurately we must sample the
waveform at a high enough rate. This is known as the sampling
rate. The sampling rate used in MRI is known as the Nyquist
frequency and relates to The Nyquist Theorem. The Nyquist
Theorem is important to MRI and it dictates that any signal must
be sampled at least twice per cycle to represent it accurately
What is the sampling time, the sampling rate and receiver
bandwidth? - ANSWER-• The sampling time is the duration of the
gradient while 256 or 512 frequencies are sampled. (eg. 8 msec)
• The sampling rate is the rate at which these samples are taken.
• The receiver bandwidth is the range of frequencies sampled
during read-out (eg 16 kHz
What does reducing bandwidth do in terms of trade-offs? -
ANSWER-Reducing the bandwidth will:
• increase sampling time
• increase SNR
• increase echo spacing for FSE scans and increase blurring
• increase chemical shift and susceptibility artefact.
