ASMIRT - MRI Accreditation Exam Latest Exam
2026 | All Questions and Correct Answers |
Verified Answers | Brand New Version!
Mild sensory effects due to static magnetic fields include: ---------CORRECT
ANSWER-----------------• Vertigo
• Nausea
• Taste Sensations
Sensory effects of the static magnetic field increase or decrease with field
strength? ---------CORRECT 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 ---------CORRECT 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.
,What risks does the static magnetic field pose in terms of implants and objects? --
-------CORRECT ANSWER-----------------Static Fields also pose hazards through the
displacement of ferro-magnetic implants and objects. The static field imparts both
a translation (attractive force) and a torque (twisting force). The strong nature of
the Static Field also has the potential to disrupt the function of Cardiac
Pacemakers. Anyone entering beyond the 5G line should be screened for
contraindications to strong Magnetic Fields. Also be aware of what is being taken
over the 5G line.
What strategies can be employed to reduce the risks of the static magnetic field
impacting on implants and objects? ---------CORRECT ANSWER-----------------•
Ferromagnetic objects may become airborne - 40 km/hr terminal velocity possible
at 1.5T
• Test any metal objects with a hand held magnet before allowing them to enter
the room.
• Keep the general public behind the 5G line. •
Possible contra-indications include pacemakers, aneurysm clips, intra-vascular
coils and stents, heart valves, penile implants, cochlear implants, ocular implants
(Fatio eyelid springs), neuro stimulators, bone growth stimulators, drug infusion
pumps.
What effect do gradient magnetic fields have on patient safety? ---------CORRECT
ANSWER-----------------Faraday's Law dictates that changing magnetic fields will
generate a voltage and a current in a conductor. The switching of the gradients
induces electrical currents in conductive tissues. Voltage generation will occur
during the rise and fall times - ie. while the field is changing. The largest voltages
will be generated at the periphery where the gradient amplitudes are highest. The
most common result of these voltages is Peripheral Nerve Stimulation (PNS).
Other side-effects are listed below;
,• magnetophosphenes - electromagnetically induced flashes of light
• seizures
• tissue heating
• peripheral nerve stimulation
• muscle contractions
• cardiac arrhythmias
• some degree of patient heating has been shown to be a result of Gradient
Magnetic effects. However, this has been shown to be so low as to be negligible
What strategies can be employed to keep gradient effects to a minimum? ---------
CORRECT ANSWER-----------------In order to keep these effects to a minimum the
following is recommended.
• keep dB/dT less than those required to produce peripheral nerve stimulation.
• max limit for dB/dT of 6 Tesla / sec
What is the cause of acoustic noise during an MRI scan? ---------CORRECT
ANSWER-----------------The characteristic noise that is heard during an MRI scan is
the result of the interaction of Lorentz forces generated by the Gradient Coil
when a current is pulsed through them in the presence of a Static Magnetic Field.
The noise results as these forces are so strong as to twist the coils on their
mounts. In some cases this can be in excess of 100dB particularly when running
EPI sequences. Thus all patients need to be provided hearing protection.
, What is the greatest concern in terms of MR safety? ---------CORRECT ANSWER-----
------------RF effects are of the greatest concern in terms of MR safety. The main
effect is the deposition of energy resulting in tissue heating. Of particular concern
are heat sensitive organs such as the eyes and testes. One of the major concerns
is where a patient has a metallic implant which results in greater heating.
RF field safety concerns increase or decrease with increasing field strength> --------
-CORRECT ANSWER-----------------The amount of energy absorbed will increase
with frequency of the RF field delivered and is therefore greater at higher field
strengths
What is SAR? ---------CORRECT ANSWER-----------------SAR= Specific Absorption Rate
- the term used to describe energy dissipation
SAR is expressed in: ---------CORRECT ANSWER-----------------Watts / kg
SAR will depend on factors including: ---------CORRECT ANSWER-----------------•
frequency (& therefore the field strength)
• RF pulse - where power deposited is proportional to (flip angle / 90)
• TR
• RF coil - transmit / receive or receive only
• volume of tissue within the coil
• conductivity of the tissue
2026 | All Questions and Correct Answers |
Verified Answers | Brand New Version!
Mild sensory effects due to static magnetic fields include: ---------CORRECT
ANSWER-----------------• Vertigo
• Nausea
• Taste Sensations
Sensory effects of the static magnetic field increase or decrease with field
strength? ---------CORRECT 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 ---------CORRECT 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.
,What risks does the static magnetic field pose in terms of implants and objects? --
-------CORRECT ANSWER-----------------Static Fields also pose hazards through the
displacement of ferro-magnetic implants and objects. The static field imparts both
a translation (attractive force) and a torque (twisting force). The strong nature of
the Static Field also has the potential to disrupt the function of Cardiac
Pacemakers. Anyone entering beyond the 5G line should be screened for
contraindications to strong Magnetic Fields. Also be aware of what is being taken
over the 5G line.
What strategies can be employed to reduce the risks of the static magnetic field
impacting on implants and objects? ---------CORRECT ANSWER-----------------•
Ferromagnetic objects may become airborne - 40 km/hr terminal velocity possible
at 1.5T
• Test any metal objects with a hand held magnet before allowing them to enter
the room.
• Keep the general public behind the 5G line. •
Possible contra-indications include pacemakers, aneurysm clips, intra-vascular
coils and stents, heart valves, penile implants, cochlear implants, ocular implants
(Fatio eyelid springs), neuro stimulators, bone growth stimulators, drug infusion
pumps.
What effect do gradient magnetic fields have on patient safety? ---------CORRECT
ANSWER-----------------Faraday's Law dictates that changing magnetic fields will
generate a voltage and a current in a conductor. The switching of the gradients
induces electrical currents in conductive tissues. Voltage generation will occur
during the rise and fall times - ie. while the field is changing. The largest voltages
will be generated at the periphery where the gradient amplitudes are highest. The
most common result of these voltages is Peripheral Nerve Stimulation (PNS).
Other side-effects are listed below;
,• magnetophosphenes - electromagnetically induced flashes of light
• seizures
• tissue heating
• peripheral nerve stimulation
• muscle contractions
• cardiac arrhythmias
• some degree of patient heating has been shown to be a result of Gradient
Magnetic effects. However, this has been shown to be so low as to be negligible
What strategies can be employed to keep gradient effects to a minimum? ---------
CORRECT ANSWER-----------------In order to keep these effects to a minimum the
following is recommended.
• keep dB/dT less than those required to produce peripheral nerve stimulation.
• max limit for dB/dT of 6 Tesla / sec
What is the cause of acoustic noise during an MRI scan? ---------CORRECT
ANSWER-----------------The characteristic noise that is heard during an MRI scan is
the result of the interaction of Lorentz forces generated by the Gradient Coil
when a current is pulsed through them in the presence of a Static Magnetic Field.
The noise results as these forces are so strong as to twist the coils on their
mounts. In some cases this can be in excess of 100dB particularly when running
EPI sequences. Thus all patients need to be provided hearing protection.
, What is the greatest concern in terms of MR safety? ---------CORRECT ANSWER-----
------------RF effects are of the greatest concern in terms of MR safety. The main
effect is the deposition of energy resulting in tissue heating. Of particular concern
are heat sensitive organs such as the eyes and testes. One of the major concerns
is where a patient has a metallic implant which results in greater heating.
RF field safety concerns increase or decrease with increasing field strength> --------
-CORRECT ANSWER-----------------The amount of energy absorbed will increase
with frequency of the RF field delivered and is therefore greater at higher field
strengths
What is SAR? ---------CORRECT ANSWER-----------------SAR= Specific Absorption Rate
- the term used to describe energy dissipation
SAR is expressed in: ---------CORRECT ANSWER-----------------Watts / kg
SAR will depend on factors including: ---------CORRECT ANSWER-----------------•
frequency (& therefore the field strength)
• RF pulse - where power deposited is proportional to (flip angle / 90)
• TR
• RF coil - transmit / receive or receive only
• volume of tissue within the coil
• conductivity of the tissue
