1|Page
ASMIRT- MRI Accreditation Actual Exam Test Bank
Newest 2025-2026/ ASMIRT- MRI Accreditation Exam
Preparation /ASMIRT- MRI Accreditation Practice Exam
With Complete 250 Questions And Correct Detailed Answers
|Already Graded A+(Newest Version!)
What are coherent gradient echo sequences used to determine? -
ANSWER-Coherent gradient echo pulse sequences produce images that
are T2* weighted. They can be used to determine if a vessel is patent or
if a region contains fluid.
For GRE coherent T2* weighted scans the following parameters are
suggested - ANSWER-For GRE coherent T2* weighted scans the
following parameters are suggested
•Flip angle 30-45 degree
•Long TE: 15ms+ (this maximises T2* contrast)
•Short TR : 20-50ms
What is an EPI sequence and what do they achieve? - ANSWER-With
echo planar imaging, a single echo train is used to collect data from all
lines of K-space during on TR period. Use of this technique
subsequently considerably shortens the acquisition time. There are two
types of EPI sequences; SE and GRE sequences. All the lines of K-space
can be acquired in a single TR (in single shot EPI) or in two or more
,2|Page
TR's. (in multishot EPI) The phase and frequency encoding gradients are
turned on and off very rapidly, a technique which allows the rapid filling
of K-space. EPI imaging is the sequence of choice for diffusion
weighted imaging, for which a EPI SE sequence is typically used. EPI
imaging is more vulnerable to magnetic susceptibility effects and
provides greater tissue contrast than does imaging with standard GRE
sequences. EPI imaging sequences are widely used to assess cerebral
perfusion.
What is DWI and what sequences are typically used to obtain DWI
images? - ANSWER-Diffusion weighting enables the operator to
distinguish between rapid diffusion of protons (unrestricted diffusion)
and slow diffusion of protons (restricted diffusion) For DWI either a EP
or a fast GRE sequence is used and two equal gradient pulses are applied
(one on each side of the 180 degree RF pulse in EP sequences)
Explain how the movement of protons in a DWI sequence impacts the
signal intensity - ANSWER-If no net movement of spinning protons
occurs between application of the two gradient pulses, the first gradient
dephases the spins and the second gradient rephases them. Thus high
signal intensity is seen. If however there is net movement of protons
these protons will be affected differently by each gradient and will thus
return lower signal intensity.
What images are produced by a DWI sequence? - ANSWER-The main
use for this technique is in the detection of stroke. These diffusion
weighted images are usually combined with an ADC map. ADC being:
,3|Page
Apparent Diffusion Coefficient. For the calculation of the ADC map,
two sets of images are obtained.
• One set is obtained without the application of a diffusion gradient
which results in a set of images with an appearance similar to that of a
T2 weighted set of images.
• The other set is obtained with a diffusion gradient. • • • • ADC
calculation is based on the negative logarithm of the ratio of the two sets
of images
What does stroke look like on ADC vs DWI? - ANSWER-The main
point of note is being able to recognise the appearance of stroke on
Diffusion and ADC maps. Firstly areas of restricted diffusion appear
dark on ADC maps and bright on diffusion weighted images. This is due
to the fact that stroke results in a region of restricted diffusion within the
brain. On the other hand areas of unrestricted diffusion appear bright on
ADC maps and dark on diffusion weighted images.
What is T2 shine through? - ANSWER-Sometimes the appearance of
high signal intensity on DWI also may be due to T2 effects or so called
T2 shine through. The absence of these effects on ADC maps allows
areas of restricted diffusion from recent stroke to appear dark and areas
of unrestricted diffusion in remote tissues or older stroke areas to appear
relatively bright.
What does subacute stroke look like? - ANSWER-Those affected
recently by a subacute stroke appear somewhat bright on DWI and may
, 4|Page
appear moderately so on ADC maps. Areas affected by old stroke are
depicted as dark areas on DWI and bright regions on ADC maps
What are the functions of gradient coils? - ANSWER-Gradients are
responsible for performing the following three tasks in encoding
• Slice Selection- locating a slice within the scan plane selected
• Spatially Encoding (locating) signal along the long axis of the anatomy
this is called frequency encoding.
• Spatially Encoding (locating) signal along the short axis of anatomy
this is called phase encoding.
The signal received is a conglomerate echo from all of the protons
excited by the RF pulse. To produce an image, the signal components
must be encoded in such a way that they can be traced back to the voxels
from which they arose.
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
ASMIRT- MRI Accreditation Actual Exam Test Bank
Newest 2025-2026/ ASMIRT- MRI Accreditation Exam
Preparation /ASMIRT- MRI Accreditation Practice Exam
With Complete 250 Questions And Correct Detailed Answers
|Already Graded A+(Newest Version!)
What are coherent gradient echo sequences used to determine? -
ANSWER-Coherent gradient echo pulse sequences produce images that
are T2* weighted. They can be used to determine if a vessel is patent or
if a region contains fluid.
For GRE coherent T2* weighted scans the following parameters are
suggested - ANSWER-For GRE coherent T2* weighted scans the
following parameters are suggested
•Flip angle 30-45 degree
•Long TE: 15ms+ (this maximises T2* contrast)
•Short TR : 20-50ms
What is an EPI sequence and what do they achieve? - ANSWER-With
echo planar imaging, a single echo train is used to collect data from all
lines of K-space during on TR period. Use of this technique
subsequently considerably shortens the acquisition time. There are two
types of EPI sequences; SE and GRE sequences. All the lines of K-space
can be acquired in a single TR (in single shot EPI) or in two or more
,2|Page
TR's. (in multishot EPI) The phase and frequency encoding gradients are
turned on and off very rapidly, a technique which allows the rapid filling
of K-space. EPI imaging is the sequence of choice for diffusion
weighted imaging, for which a EPI SE sequence is typically used. EPI
imaging is more vulnerable to magnetic susceptibility effects and
provides greater tissue contrast than does imaging with standard GRE
sequences. EPI imaging sequences are widely used to assess cerebral
perfusion.
What is DWI and what sequences are typically used to obtain DWI
images? - ANSWER-Diffusion weighting enables the operator to
distinguish between rapid diffusion of protons (unrestricted diffusion)
and slow diffusion of protons (restricted diffusion) For DWI either a EP
or a fast GRE sequence is used and two equal gradient pulses are applied
(one on each side of the 180 degree RF pulse in EP sequences)
Explain how the movement of protons in a DWI sequence impacts the
signal intensity - ANSWER-If no net movement of spinning protons
occurs between application of the two gradient pulses, the first gradient
dephases the spins and the second gradient rephases them. Thus high
signal intensity is seen. If however there is net movement of protons
these protons will be affected differently by each gradient and will thus
return lower signal intensity.
What images are produced by a DWI sequence? - ANSWER-The main
use for this technique is in the detection of stroke. These diffusion
weighted images are usually combined with an ADC map. ADC being:
,3|Page
Apparent Diffusion Coefficient. For the calculation of the ADC map,
two sets of images are obtained.
• One set is obtained without the application of a diffusion gradient
which results in a set of images with an appearance similar to that of a
T2 weighted set of images.
• The other set is obtained with a diffusion gradient. • • • • ADC
calculation is based on the negative logarithm of the ratio of the two sets
of images
What does stroke look like on ADC vs DWI? - ANSWER-The main
point of note is being able to recognise the appearance of stroke on
Diffusion and ADC maps. Firstly areas of restricted diffusion appear
dark on ADC maps and bright on diffusion weighted images. This is due
to the fact that stroke results in a region of restricted diffusion within the
brain. On the other hand areas of unrestricted diffusion appear bright on
ADC maps and dark on diffusion weighted images.
What is T2 shine through? - ANSWER-Sometimes the appearance of
high signal intensity on DWI also may be due to T2 effects or so called
T2 shine through. The absence of these effects on ADC maps allows
areas of restricted diffusion from recent stroke to appear dark and areas
of unrestricted diffusion in remote tissues or older stroke areas to appear
relatively bright.
What does subacute stroke look like? - ANSWER-Those affected
recently by a subacute stroke appear somewhat bright on DWI and may
, 4|Page
appear moderately so on ADC maps. Areas affected by old stroke are
depicted as dark areas on DWI and bright regions on ADC maps
What are the functions of gradient coils? - ANSWER-Gradients are
responsible for performing the following three tasks in encoding
• Slice Selection- locating a slice within the scan plane selected
• Spatially Encoding (locating) signal along the long axis of the anatomy
this is called frequency encoding.
• Spatially Encoding (locating) signal along the short axis of anatomy
this is called phase encoding.
The signal received is a conglomerate echo from all of the protons
excited by the RF pulse. To produce an image, the signal components
must be encoded in such a way that they can be traced back to the voxels
from which they arose.
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
