ASMIRT - MRI ACCREDITATION NEWEST EXAM ACTUAL
EXAM 2026 | WITH COMPLETE ALL QUESTIONS AND
CORRECT ANSWERS | VERIFIED //GRADED A+//|
BRAND NEW VERSION!
What strategies can be employed to keep gradient
effects to a minimum?
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?
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.
Page 1 of 41
,What is the greatest concern in terms of MR safety?
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>
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?
SAR= Specific Absorption Rate - the term used to
describe energy dissipation
SAR is expressed in:
Watts / kg
Page 2 of 41
,SAR will depend on factors including:
• 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
What determines the SAR calculation?
The SAR is calculated for each sequence on the basis of
the sequence parameters and the patient weight
What are the FDA recommendations regarding SAR?
• Maximum SAR of 0.4 W/kg (whole body)
• 3.2 W/kg (head)
• 8.0 W/kg (in any one gram of tissue)
• RF exposure should be insufficient to produce a core
temperature increase of 1 degree C
Page 3 of 41
, Why is patient heating a concern in MRI?
• Heating will also vary with the state of the patient's
thermo-regulatory system, the ambient temperature,
the humidity and the air flow around the patient.
• The eye and the testes are particularly sensitive
organs due to a low capacity for heat dissipation.
• Excessive RF exposure and temperature increase can
lead to an increase in blood pressure and heart rate.
Mild sensory effects due to static magnetic fields
include:
• Vertigo
• Nausea
• Taste Sensations
Sensory effects of the static magnetic field increase or
decrease with field strength?
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
Page 4 of 41
EXAM 2026 | WITH COMPLETE ALL QUESTIONS AND
CORRECT ANSWERS | VERIFIED //GRADED A+//|
BRAND NEW VERSION!
What strategies can be employed to keep gradient
effects to a minimum?
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?
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.
Page 1 of 41
,What is the greatest concern in terms of MR safety?
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>
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?
SAR= Specific Absorption Rate - the term used to
describe energy dissipation
SAR is expressed in:
Watts / kg
Page 2 of 41
,SAR will depend on factors including:
• 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
What determines the SAR calculation?
The SAR is calculated for each sequence on the basis of
the sequence parameters and the patient weight
What are the FDA recommendations regarding SAR?
• Maximum SAR of 0.4 W/kg (whole body)
• 3.2 W/kg (head)
• 8.0 W/kg (in any one gram of tissue)
• RF exposure should be insufficient to produce a core
temperature increase of 1 degree C
Page 3 of 41
, Why is patient heating a concern in MRI?
• Heating will also vary with the state of the patient's
thermo-regulatory system, the ambient temperature,
the humidity and the air flow around the patient.
• The eye and the testes are particularly sensitive
organs due to a low capacity for heat dissipation.
• Excessive RF exposure and temperature increase can
lead to an increase in blood pressure and heart rate.
Mild sensory effects due to static magnetic fields
include:
• Vertigo
• Nausea
• Taste Sensations
Sensory effects of the static magnetic field increase or
decrease with field strength?
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
Page 4 of 41
