MRI Metallic Foreign Body Screening
Exam Practice Questions and Correct
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Question 1
What is the primary purpose of screening a patient for metallic foreign bodies
before an MRI examination?
A. To determine whether contrast media is required
B. To estimate the patient's total body weight
C. To identify objects that could pose an MRI-related safety risk
D. To determine the patient's preferred imaging position
Correct Answer: C
The purpose of metallic foreign-body screening is to identify potentially hazardous
objects before the patient enters the MR environment. Ferromagnetic objects may
experience attraction or torque, while conductive objects may present heating
risks. Proper screening helps prevent injury and other adverse events.
Question 2
Which MRI field is primarily responsible for attracting a ferromagnetic foreign
body toward the magnet?
A. Static magnetic field
B. Radiofrequency field
,C. Gradient magnetic field
D. Acoustic field
Correct Answer: A
The static magnetic field can exert translational forces on susceptible
ferromagnetic objects. These forces can cause an object to move toward the
magnet or toward a region of higher magnetic-field strength.
Question 3
Why can a ferromagnetic foreign body become dangerous during MRI?
A. It always produces ionizing radiation
B. It can become radioactive inside the scanner
C. It automatically dissolves in the magnetic field
D. It may experience displacement or torque
Correct Answer: D
Ferromagnetic objects can be subjected to translational forces and torque in the
MR environment. If the object is located within the body, movement or rotation
may damage surrounding tissue.
Question 4
Which patient history should raise particular concern for a possible metallic
orbital foreign body?
A. Previous dental cleaning
B. History of metal grinding or hammering without documented eye protection
C. Previous abdominal ultrasound
D. Seasonal allergies
Correct Answer: B
Activities such as metal grinding, cutting, or hammering can propel small metallic
fragments toward the eyes. A relevant occupational or recreational history should
therefore prompt careful assessment for possible orbital foreign bodies.
,Question 5
Which location is considered particularly important when assessing a suspected
metallic foreign body?
A. Thigh muscle
B. Calf subcutaneous tissue
C. Orbit
D. Fingernail
Correct Answer: C
The orbit is a critical location because a metallic fragment near the eye can
potentially move or experience torque during MRI and injure sensitive ocular
structures. ACR MR safety guidance specifically highlights orbital foreign bodies as
requiring careful assessment.
Question 6
A patient reports that a small metal fragment entered the eye several years ago.
What is the most appropriate screening principle?
A. Assume the fragment is harmless because the injury was old
B. Proceed if the patient has no current eye symptoms
C. Proceed if the patient cannot feel the fragment
D. Treat the history as requiring further evaluation before MRI
Correct Answer: D
The absence of current symptoms does not establish MRI safety. A retained
metallic fragment may remain present even after an old injury, so the suspected
foreign body should be appropriately evaluated before MRI.
Question 7
Which characteristic of a foreign body is most directly relevant to its potential
magnetic attraction?
, A. Magnetic susceptibility
B. Skin color
C. Patient age
D. Body temperature
Correct Answer: A
Magnetic susceptibility describes how a material responds to a magnetic field.
Ferromagnetic materials can experience substantial attraction and torque, making
their magnetic properties important in MRI safety assessment.
Question 8
Why is the exact location of a metallic foreign body important during MRI
screening?
A. Location determines the patient's blood pressure
B. Location determines whether the patient requires contrast
C. Location affects the potential consequences of movement, torque, or heating
D. Location determines the scanner's image resolution
Correct Answer: C
The clinical risk from a foreign body depends partly on where it is located.
Movement of an object near a critical structure, such as the eye, brain, spinal cord,
or major blood vessel, may have much more serious consequences than
movement in less vulnerable tissue.
Question 9
Which type of information is most useful when evaluating a reported metallic
foreign-body injury?
A. The patient's preferred MRI sequence
B. The mechanism, location, and circumstances of the injury
C. The patient's previous contrast reaction
D. The patient's fasting history
Exam Practice Questions and Correct
Answers (Verified Answers) Plus
Rationales 2027 Q&A | Instant
Download Pdf
Question 1
What is the primary purpose of screening a patient for metallic foreign bodies
before an MRI examination?
A. To determine whether contrast media is required
B. To estimate the patient's total body weight
C. To identify objects that could pose an MRI-related safety risk
D. To determine the patient's preferred imaging position
Correct Answer: C
The purpose of metallic foreign-body screening is to identify potentially hazardous
objects before the patient enters the MR environment. Ferromagnetic objects may
experience attraction or torque, while conductive objects may present heating
risks. Proper screening helps prevent injury and other adverse events.
Question 2
Which MRI field is primarily responsible for attracting a ferromagnetic foreign
body toward the magnet?
A. Static magnetic field
B. Radiofrequency field
,C. Gradient magnetic field
D. Acoustic field
Correct Answer: A
The static magnetic field can exert translational forces on susceptible
ferromagnetic objects. These forces can cause an object to move toward the
magnet or toward a region of higher magnetic-field strength.
Question 3
Why can a ferromagnetic foreign body become dangerous during MRI?
A. It always produces ionizing radiation
B. It can become radioactive inside the scanner
C. It automatically dissolves in the magnetic field
D. It may experience displacement or torque
Correct Answer: D
Ferromagnetic objects can be subjected to translational forces and torque in the
MR environment. If the object is located within the body, movement or rotation
may damage surrounding tissue.
Question 4
Which patient history should raise particular concern for a possible metallic
orbital foreign body?
A. Previous dental cleaning
B. History of metal grinding or hammering without documented eye protection
C. Previous abdominal ultrasound
D. Seasonal allergies
Correct Answer: B
Activities such as metal grinding, cutting, or hammering can propel small metallic
fragments toward the eyes. A relevant occupational or recreational history should
therefore prompt careful assessment for possible orbital foreign bodies.
,Question 5
Which location is considered particularly important when assessing a suspected
metallic foreign body?
A. Thigh muscle
B. Calf subcutaneous tissue
C. Orbit
D. Fingernail
Correct Answer: C
The orbit is a critical location because a metallic fragment near the eye can
potentially move or experience torque during MRI and injure sensitive ocular
structures. ACR MR safety guidance specifically highlights orbital foreign bodies as
requiring careful assessment.
Question 6
A patient reports that a small metal fragment entered the eye several years ago.
What is the most appropriate screening principle?
A. Assume the fragment is harmless because the injury was old
B. Proceed if the patient has no current eye symptoms
C. Proceed if the patient cannot feel the fragment
D. Treat the history as requiring further evaluation before MRI
Correct Answer: D
The absence of current symptoms does not establish MRI safety. A retained
metallic fragment may remain present even after an old injury, so the suspected
foreign body should be appropriately evaluated before MRI.
Question 7
Which characteristic of a foreign body is most directly relevant to its potential
magnetic attraction?
, A. Magnetic susceptibility
B. Skin color
C. Patient age
D. Body temperature
Correct Answer: A
Magnetic susceptibility describes how a material responds to a magnetic field.
Ferromagnetic materials can experience substantial attraction and torque, making
their magnetic properties important in MRI safety assessment.
Question 8
Why is the exact location of a metallic foreign body important during MRI
screening?
A. Location determines the patient's blood pressure
B. Location determines whether the patient requires contrast
C. Location affects the potential consequences of movement, torque, or heating
D. Location determines the scanner's image resolution
Correct Answer: C
The clinical risk from a foreign body depends partly on where it is located.
Movement of an object near a critical structure, such as the eye, brain, spinal cord,
or major blood vessel, may have much more serious consequences than
movement in less vulnerable tissue.
Question 9
Which type of information is most useful when evaluating a reported metallic
foreign-body injury?
A. The patient's preferred MRI sequence
B. The mechanism, location, and circumstances of the injury
C. The patient's previous contrast reaction
D. The patient's fasting history
