ASMIRT MRI Accreditation Exam:
100 Practice Questions and Answer
Explanations
Part One: Patient Care, Safety, and
Contrast Media (1–25)
1. A patient with a known cardiac pacemaker identified as MR-Unsafe presents for an MRI.
What is the most appropriate action?
A. Proceed with the scan using a lower SAR setting.
B. Proceed with the scan but monitor the patient's ECG closely.
C. Do not perform the MRI and consult with the patient's cardiologist.
D. Perform the scan only on a 1.5T scanner, not a 3T.
Answer: C
Explanation: An MR-Unsafe implant poses a significant risk to the patient, including device
malfunction, heating, or movement, which can be fatal. The only safe course is to avoid the
MRI and consult the cardiologist to determine if an alternative imaging modality is
appropriate or if the device can be safely managed .
2. Which of the following is the primary safety concern associated with the static magnetic
field of an MRI scanner?
A. Heating of implanted devices.
B. The projectile effect on ferromagnetic objects.
C. Peripheral nerve stimulation.
D. Acoustic noise.
Answer: B
Explanation: The static magnetic field (B0) exerts a powerful attractive force on
ferromagnetic objects. This can turn everyday items into dangerous projectiles, causing
serious injury or death. Heating is caused by RF energy, peripheral nerve stimulation by
gradient fields, and acoustic noise by gradient coil vibration .
3. A patient is referred for an MRI with a history of metal fragments in the eye from a
workplace accident. What is the priority action?
A. Proceed with the scan, as the fragments are likely too small to be a risk.
B. Ask the patient to remove their contact lenses and proceed.
C. Request a skull X-ray or CT to rule out intraocular metallic foreign bodies.
D. Scan the patient but use a head coil to limit the field of view.
,Answer: C
Explanation: Metallic foreign bodies in the eye are an absolute contraindication for MRI
unless proven to be non-ferromagnetic. A skull X-ray or CT is the standard method to detect
and characterise such fragments before scanning .
4. The specific absorption rate (SAR) is a measure of:
A. The strength of the magnetic field.
B. The rate at which RF energy is absorbed by the patient's tissue.
C. The speed of the gradient switching.
D. The loudness of the acoustic noise.
Answer: B
Explanation: SAR quantifies the amount of RF power absorbed per unit mass of tissue,
measured in watts per kilogram (W/kg). Excessive RF absorption can cause tissue heating
and burns .
5. A patient is 12 weeks pregnant. The referring doctor has requested an MRI for a
suspected appendicitis. What is the most appropriate course of action?
A. Refuse the scan until after the pregnancy.
B. Perform the scan without any modifications.
C. Consult with the radiologist regarding risk-benefit, as MRI is generally preferred over CT in
pregnancy when appropriate.
D. Perform the scan only with a contrast agent.
Answer: C
Explanation: MRI is generally considered safe in pregnancy and is often preferred over CT
when imaging is necessary. However, the decision should involve consultation with the
radiologist to weigh the risks and benefits. Contrast should be avoided unless essential .
6. What is the "5G line" in MRI safety?
A. A line marking the area where RF heating is a concern.
B. A safety boundary to keep the general public, who may not be screened, away from the
strong magnetic field.
C. A line indicating the range of the gradient magnetic fields.
D. A line defining the acoustic noise hazard zone.
Answer: B
Explanation: The 5-gauss line marks the boundary of the static magnetic field at which the
field strength is 5 gauss. It is used to restrict access by unscreened individuals who may have
ferromagnetic implants or objects .
7. What is the molecular make-up of Gadolinium that makes it useful as an MRI contrast
agent?
A. It has 7 unpaired electrons, giving it a large magnetic moment.
B. It has a high atomic number.
C. It is naturally radioactive.
, D. It has a long half-life in the body.
Answer: A
Explanation: Gadolinium has 7 unpaired electrons which gives rise to a large magnetic
moment, making it the most efficient proton relaxation enhancer .
8. Why is gadolinium not suitable for use as a contrast agent in its free ionic form?
A. It is not visible on MRI.
B. It is toxic and forms insoluble salts taken up by the liver.
C. It is rapidly excreted.
D. It has no effect on relaxation times.
Answer: B
Explanation: In its free ionic form, gadolinium is toxic and forms insoluble salts which are
taken up by the liver. It must be bound to a ligand to form a chelate for safe administration .
9. What is the standard dose for a gadolinium-based contrast agent (GBCA)?
A. 0.01 mmol/kg
B. 0.1 mmol/kg
C. 1.0 mmol/kg
D. 10 mmol/kg
Answer: B
Explanation: The standard dose for GBCA is 0.1 mmol/kg (2 mL/kg). The maximum dose is
triple dose at 0.3 mmol/kg .
10. What is the primary excretion pathway for gadolinium-based contrast agents?
A. Via the liver in bile.
B. Via the kidneys in urine.
C. Via the lungs in exhaled air.
D. Via the skin in sweat.
Answer: B
Explanation: GBCAs are primarily excreted via the kidneys: 80% in 3 hours, 95% in 24 hours,
and 98% via feces and urine in one week .
11. What enhances in a brain scan following contrast administration in a patient with an
intact blood-brain barrier?
A. Intra-axial brain parenchyma.
B. Extra-axial areas such as the falx, pituitary, and choroid plexus.
C. The ventricles.
D. The cerebral cortex.
Answer: B
Explanation: Extra-axial areas outside the BBB such as the falx, pituitary and choroid plexus
will enhance. With an intact BBB, intra-axial areas will not enhance. Disruption of the BBB
allows accumulation of gadolinium in lesions .
100 Practice Questions and Answer
Explanations
Part One: Patient Care, Safety, and
Contrast Media (1–25)
1. A patient with a known cardiac pacemaker identified as MR-Unsafe presents for an MRI.
What is the most appropriate action?
A. Proceed with the scan using a lower SAR setting.
B. Proceed with the scan but monitor the patient's ECG closely.
C. Do not perform the MRI and consult with the patient's cardiologist.
D. Perform the scan only on a 1.5T scanner, not a 3T.
Answer: C
Explanation: An MR-Unsafe implant poses a significant risk to the patient, including device
malfunction, heating, or movement, which can be fatal. The only safe course is to avoid the
MRI and consult the cardiologist to determine if an alternative imaging modality is
appropriate or if the device can be safely managed .
2. Which of the following is the primary safety concern associated with the static magnetic
field of an MRI scanner?
A. Heating of implanted devices.
B. The projectile effect on ferromagnetic objects.
C. Peripheral nerve stimulation.
D. Acoustic noise.
Answer: B
Explanation: The static magnetic field (B0) exerts a powerful attractive force on
ferromagnetic objects. This can turn everyday items into dangerous projectiles, causing
serious injury or death. Heating is caused by RF energy, peripheral nerve stimulation by
gradient fields, and acoustic noise by gradient coil vibration .
3. A patient is referred for an MRI with a history of metal fragments in the eye from a
workplace accident. What is the priority action?
A. Proceed with the scan, as the fragments are likely too small to be a risk.
B. Ask the patient to remove their contact lenses and proceed.
C. Request a skull X-ray or CT to rule out intraocular metallic foreign bodies.
D. Scan the patient but use a head coil to limit the field of view.
,Answer: C
Explanation: Metallic foreign bodies in the eye are an absolute contraindication for MRI
unless proven to be non-ferromagnetic. A skull X-ray or CT is the standard method to detect
and characterise such fragments before scanning .
4. The specific absorption rate (SAR) is a measure of:
A. The strength of the magnetic field.
B. The rate at which RF energy is absorbed by the patient's tissue.
C. The speed of the gradient switching.
D. The loudness of the acoustic noise.
Answer: B
Explanation: SAR quantifies the amount of RF power absorbed per unit mass of tissue,
measured in watts per kilogram (W/kg). Excessive RF absorption can cause tissue heating
and burns .
5. A patient is 12 weeks pregnant. The referring doctor has requested an MRI for a
suspected appendicitis. What is the most appropriate course of action?
A. Refuse the scan until after the pregnancy.
B. Perform the scan without any modifications.
C. Consult with the radiologist regarding risk-benefit, as MRI is generally preferred over CT in
pregnancy when appropriate.
D. Perform the scan only with a contrast agent.
Answer: C
Explanation: MRI is generally considered safe in pregnancy and is often preferred over CT
when imaging is necessary. However, the decision should involve consultation with the
radiologist to weigh the risks and benefits. Contrast should be avoided unless essential .
6. What is the "5G line" in MRI safety?
A. A line marking the area where RF heating is a concern.
B. A safety boundary to keep the general public, who may not be screened, away from the
strong magnetic field.
C. A line indicating the range of the gradient magnetic fields.
D. A line defining the acoustic noise hazard zone.
Answer: B
Explanation: The 5-gauss line marks the boundary of the static magnetic field at which the
field strength is 5 gauss. It is used to restrict access by unscreened individuals who may have
ferromagnetic implants or objects .
7. What is the molecular make-up of Gadolinium that makes it useful as an MRI contrast
agent?
A. It has 7 unpaired electrons, giving it a large magnetic moment.
B. It has a high atomic number.
C. It is naturally radioactive.
, D. It has a long half-life in the body.
Answer: A
Explanation: Gadolinium has 7 unpaired electrons which gives rise to a large magnetic
moment, making it the most efficient proton relaxation enhancer .
8. Why is gadolinium not suitable for use as a contrast agent in its free ionic form?
A. It is not visible on MRI.
B. It is toxic and forms insoluble salts taken up by the liver.
C. It is rapidly excreted.
D. It has no effect on relaxation times.
Answer: B
Explanation: In its free ionic form, gadolinium is toxic and forms insoluble salts which are
taken up by the liver. It must be bound to a ligand to form a chelate for safe administration .
9. What is the standard dose for a gadolinium-based contrast agent (GBCA)?
A. 0.01 mmol/kg
B. 0.1 mmol/kg
C. 1.0 mmol/kg
D. 10 mmol/kg
Answer: B
Explanation: The standard dose for GBCA is 0.1 mmol/kg (2 mL/kg). The maximum dose is
triple dose at 0.3 mmol/kg .
10. What is the primary excretion pathway for gadolinium-based contrast agents?
A. Via the liver in bile.
B. Via the kidneys in urine.
C. Via the lungs in exhaled air.
D. Via the skin in sweat.
Answer: B
Explanation: GBCAs are primarily excreted via the kidneys: 80% in 3 hours, 95% in 24 hours,
and 98% via feces and urine in one week .
11. What enhances in a brain scan following contrast administration in a patient with an
intact blood-brain barrier?
A. Intra-axial brain parenchyma.
B. Extra-axial areas such as the falx, pituitary, and choroid plexus.
C. The ventricles.
D. The cerebral cortex.
Answer: B
Explanation: Extra-axial areas outside the BBB such as the falx, pituitary and choroid plexus
will enhance. With an intact BBB, intra-axial areas will not enhance. Disruption of the BBB
allows accumulation of gadolinium in lesions .
