Test Bank For Fundamentals of Body
MRI, 3rd Edition
BY
Christopher G. Roth & Haresh Naringrekar & Sandeep Deshmukh
Chapter 1: Body MRI Physics of MRI Safety
1. What is the primary principle behind Magnetic Resonance Imaging (MRI)?
A. Ionization of atoms
B. Alignment of hydrogen nuclei in a magnetic field
C. Propagation of sound waves
D. Reflection of X-rays
Answer: B. Alignment of hydrogen nuclei in a magnetic field
Rationale: MRI is based on the principle that hydrogen nuclei (protons) align with a
magnetic field. When exposed to a strong magnetic field, protons in the body align
, parallel or antiparallel to the magnetic field. Radiofrequency pulses are used to disturb
this alignment, and the response is measured to create an image.
DIF: Moderate
TOP: Physics of MRI
MSC: Knowledge
2. Which of the following is a safety concern when operating an MRI scanner?
A. High levels of ionizing radiation
B. Strong magnetic fields causing attraction of ferromagnetic objects
C. Exposure to sound waves
D. Use of contrast agents
Answer: B. Strong magnetic fields causing attraction of ferromagnetic objects
Rationale: MRI machines produce powerful magnetic fields that can attract
ferromagnetic objects (such as steel tools or certain implants), creating a significant
safety hazard. Careful screening is essential to ensure that such objects are not brought
into the MRI room. DIF: High
TOP: MRI Safety
MSC: Application
3. Which of the following is NOT a common contraindication for MRI?
A. Cardiac pacemakers
B. Cochlear implants
C. Pregnancy
D. Metal implants in the body
Answer: C. Pregnancy
Rationale: While certain contraindications exist for MRI, such as cardiac pacemakers
and cochlear implants due to safety concerns with the magnetic field, pregnancy itself is
not an absolute contraindication. However, MRI should be avoided in the first trimester
unless necessary for medical reasons.
DIF: Low
TOP: MRI Safety
MSC: Application
4. The concept of resonance in MRI refers to:
A. The reflection of radio waves
B. The absorption of energy by protons at a specific frequency
C. The movement of electrons in the magnetic field
D. The gradient changes in the magnetic field
Answer: B. The absorption of energy by protons at a specific frequency Rationale:
Resonance occurs when protons in the body absorb energy from a radiofrequency pulse
at a specific frequency. This causes them to move to a higher energy state. When the
pulse is turned off, the protons return to their lower energy state, emitting energy that
can be detected to form an image.
DIF: Moderate
TOP: Physics of MRI
, MSC: Comprehension
5. What is the most commonly used contrast agent in MRI scans?
A. Barium sulfate
B. Gadolinium-based compounds
C. Iodine-based compounds
D. Xenon gas
Answer: B. Gadolinium-based compounds
Rationale: Gadolinium-based contrast agents are commonly used in MRI to enhance the
quality of the images, particularly for imaging blood vessels and tissues. Gadolinium
improves signal contrast by altering the relaxation times of hydrogen protons.
DIF: Low
TOP: MRI Contrast
MSC: Knowledge
6. Which of the following is a key safety measure in MRI environments?
A. Maintaining a 3-meter radius around the scanner
B. Ensuring all staff wear lead aprons
C. Keeping all ferromagnetic objects out of the MRI room
D. Allowing patients to wear any clothing in the scanner
Answer: C. Keeping all ferromagnetic objects out of the MRI room
Rationale: Due to the powerful magnetic field in MRI machines, it is crucial to keep all
ferromagnetic objects out of the MRI room to avoid accidents, such as objects being
pulled toward the magnet.
DIF: High
TOP: MRI Safety
MSC: Application
7. What does the term “T1 relaxation” refer to in MRI?
A. The recovery of longitudinal magnetization
B. The decay of transverse magnetization
C. The spin rate of protons
D. The gradient of the magnetic field
Answer: A. The recovery of longitudinal magnetization
Rationale: T1 relaxation refers to the process by which protons return to their
equilibrium state along the longitudinal axis after being disturbed by a radiofrequency
pulse. This is known as longitudinal relaxation, and it plays a role in determining tissue
contrast in MRI imaging.
DIF: Moderate
TOP: Physics of MRI
MSC: Knowledge
8. Which of the following is a potential risk associated with gadolinium-based contrast
agents?
A. Nephrogenic systemic fibrosis (NSF)
B. Bone marrow suppression
, C. Radiodermatitis
D. Cardiac arrhythmias
Answer: A. Nephrogenic systemic fibrosis (NSF)
Rationale: Gadolinium-based contrast agents can be associated with nephrogenic
systemic fibrosis (NSF) in patients with severe renal impairment. NSF is a rare but
serious condition that can cause fibrosis in the skin and internal organs.
DIF: High
TOP: MRI Safety
MSC: Comprehension
9. Which MRI safety feature is most commonly used to prevent injury from the magnetic
field?
A. Magnetic shielding
B. Radiofrequency coils
C. Cryogen cooling
D. Pressure pads
Answer: A. Magnetic shielding
Rationale: Magnetic shielding is a safety feature used to contain the strong magnetic
field within the MRI room, preventing it from affecting nearby areas and reducing the
risk of injury from ferromagnetic objects being attracted to the magnet.
DIF: Moderate
TOP: MRI Safety
MSC: Knowledge
10. What is the purpose of the gradient coils in an MRI machine?
A. To generate the magnetic field
B. To produce radiofrequency pulses
C. To allow spatial localization of the signal
D. To enhance contrast resolution
Answer: C. To allow spatial localization of the signal
Rationale: Gradient coils are responsible for generating a varying magnetic field within
the MRI scanner, which allows spatial localization of the signal and helps in the
construction of detailed images.
DIF: Moderate
TOP: Physics of MRI
MSC: Comprehension
11. Which of the following is a common safety protocol in an MRI room to prevent
accidents?
A. Wearing radiation protection garments
B. Screening patients and staff for implants and devices
C. Limiting the MRI procedure to only 15 minutes
D. Ensuring all personnel are in direct communication with the scanner
Answer: B. Screening patients and staff for implants and devices
MRI, 3rd Edition
BY
Christopher G. Roth & Haresh Naringrekar & Sandeep Deshmukh
Chapter 1: Body MRI Physics of MRI Safety
1. What is the primary principle behind Magnetic Resonance Imaging (MRI)?
A. Ionization of atoms
B. Alignment of hydrogen nuclei in a magnetic field
C. Propagation of sound waves
D. Reflection of X-rays
Answer: B. Alignment of hydrogen nuclei in a magnetic field
Rationale: MRI is based on the principle that hydrogen nuclei (protons) align with a
magnetic field. When exposed to a strong magnetic field, protons in the body align
, parallel or antiparallel to the magnetic field. Radiofrequency pulses are used to disturb
this alignment, and the response is measured to create an image.
DIF: Moderate
TOP: Physics of MRI
MSC: Knowledge
2. Which of the following is a safety concern when operating an MRI scanner?
A. High levels of ionizing radiation
B. Strong magnetic fields causing attraction of ferromagnetic objects
C. Exposure to sound waves
D. Use of contrast agents
Answer: B. Strong magnetic fields causing attraction of ferromagnetic objects
Rationale: MRI machines produce powerful magnetic fields that can attract
ferromagnetic objects (such as steel tools or certain implants), creating a significant
safety hazard. Careful screening is essential to ensure that such objects are not brought
into the MRI room. DIF: High
TOP: MRI Safety
MSC: Application
3. Which of the following is NOT a common contraindication for MRI?
A. Cardiac pacemakers
B. Cochlear implants
C. Pregnancy
D. Metal implants in the body
Answer: C. Pregnancy
Rationale: While certain contraindications exist for MRI, such as cardiac pacemakers
and cochlear implants due to safety concerns with the magnetic field, pregnancy itself is
not an absolute contraindication. However, MRI should be avoided in the first trimester
unless necessary for medical reasons.
DIF: Low
TOP: MRI Safety
MSC: Application
4. The concept of resonance in MRI refers to:
A. The reflection of radio waves
B. The absorption of energy by protons at a specific frequency
C. The movement of electrons in the magnetic field
D. The gradient changes in the magnetic field
Answer: B. The absorption of energy by protons at a specific frequency Rationale:
Resonance occurs when protons in the body absorb energy from a radiofrequency pulse
at a specific frequency. This causes them to move to a higher energy state. When the
pulse is turned off, the protons return to their lower energy state, emitting energy that
can be detected to form an image.
DIF: Moderate
TOP: Physics of MRI
, MSC: Comprehension
5. What is the most commonly used contrast agent in MRI scans?
A. Barium sulfate
B. Gadolinium-based compounds
C. Iodine-based compounds
D. Xenon gas
Answer: B. Gadolinium-based compounds
Rationale: Gadolinium-based contrast agents are commonly used in MRI to enhance the
quality of the images, particularly for imaging blood vessels and tissues. Gadolinium
improves signal contrast by altering the relaxation times of hydrogen protons.
DIF: Low
TOP: MRI Contrast
MSC: Knowledge
6. Which of the following is a key safety measure in MRI environments?
A. Maintaining a 3-meter radius around the scanner
B. Ensuring all staff wear lead aprons
C. Keeping all ferromagnetic objects out of the MRI room
D. Allowing patients to wear any clothing in the scanner
Answer: C. Keeping all ferromagnetic objects out of the MRI room
Rationale: Due to the powerful magnetic field in MRI machines, it is crucial to keep all
ferromagnetic objects out of the MRI room to avoid accidents, such as objects being
pulled toward the magnet.
DIF: High
TOP: MRI Safety
MSC: Application
7. What does the term “T1 relaxation” refer to in MRI?
A. The recovery of longitudinal magnetization
B. The decay of transverse magnetization
C. The spin rate of protons
D. The gradient of the magnetic field
Answer: A. The recovery of longitudinal magnetization
Rationale: T1 relaxation refers to the process by which protons return to their
equilibrium state along the longitudinal axis after being disturbed by a radiofrequency
pulse. This is known as longitudinal relaxation, and it plays a role in determining tissue
contrast in MRI imaging.
DIF: Moderate
TOP: Physics of MRI
MSC: Knowledge
8. Which of the following is a potential risk associated with gadolinium-based contrast
agents?
A. Nephrogenic systemic fibrosis (NSF)
B. Bone marrow suppression
, C. Radiodermatitis
D. Cardiac arrhythmias
Answer: A. Nephrogenic systemic fibrosis (NSF)
Rationale: Gadolinium-based contrast agents can be associated with nephrogenic
systemic fibrosis (NSF) in patients with severe renal impairment. NSF is a rare but
serious condition that can cause fibrosis in the skin and internal organs.
DIF: High
TOP: MRI Safety
MSC: Comprehension
9. Which MRI safety feature is most commonly used to prevent injury from the magnetic
field?
A. Magnetic shielding
B. Radiofrequency coils
C. Cryogen cooling
D. Pressure pads
Answer: A. Magnetic shielding
Rationale: Magnetic shielding is a safety feature used to contain the strong magnetic
field within the MRI room, preventing it from affecting nearby areas and reducing the
risk of injury from ferromagnetic objects being attracted to the magnet.
DIF: Moderate
TOP: MRI Safety
MSC: Knowledge
10. What is the purpose of the gradient coils in an MRI machine?
A. To generate the magnetic field
B. To produce radiofrequency pulses
C. To allow spatial localization of the signal
D. To enhance contrast resolution
Answer: C. To allow spatial localization of the signal
Rationale: Gradient coils are responsible for generating a varying magnetic field within
the MRI scanner, which allows spatial localization of the signal and helps in the
construction of detailed images.
DIF: Moderate
TOP: Physics of MRI
MSC: Comprehension
11. Which of the following is a common safety protocol in an MRI room to prevent
accidents?
A. Wearing radiation protection garments
B. Screening patients and staff for implants and devices
C. Limiting the MRI procedure to only 15 minutes
D. Ensuring all personnel are in direct communication with the scanner
Answer: B. Screening patients and staff for implants and devices
