MRI Technology and Clinical Applications
Questions with 100% Correct Answers
What provides the external magnetic field in MRI? Correct Answer The MRI machine
The patient is said to be ____ by the MRI machine Correct Answer magnetised
Where does the radiofrequency pulse come from? Correct Answer the MRI machine
What does the radiofrequency pulse provided by the MRI machine do? Correct Answer
allows patient photons to spine in phase with each other
Where are the coils used to the detect the signal placed? Correct Answer on the MRI
table
How are MRI signals detected Correct Answer Faradays law of electromagnetic
induction
Faradays law of electromagnetic induction states that Correct Answer if a conductive
loop is placed in an
Area of moving magnetic field, a current will be induced.
Magnetic field strength is measured in... Correct Answer Tesla (T)
1 Tesla is Correct Answer 10,000 Gauss (G)
Many MRI machines have strength ranging from Correct Answer 0.5T to 3T
Research MRI machines commonly have magnetic of what strength ? Correct Answer
7T
Types of magnets used in MRI Correct Answer permanent magnets and electromagnets
What metals will retain their magnetism once magnetised? Correct Answer iron, cobalt
and nickel
Metals used as permanent magnets are those that... Correct Answer can retain their
magnetism once magnetised
What direction does the magnetic field run in permanent magnet MRI machines?
Correct Answer vertically
If a current is passed through a long straight wire, .... Correct Answer a magnetic field is
produced around the wire
, The strength of magnetic field aroudn a long straight wire is proportional to.... Correct
Answer the amount of current
What is a solenoid magnet? Correct Answer an electromagnet that uses a loop of wire
The strength of the magnetic field of a solenoid magnet is proportional to Correct
Answer the amount of loops and strength of current
The magnetic field strength of electromagnets used in MRI is Correct Answer 0.2T to
0.3T
What is a superconductive material? Correct Answer a material that has no resistance
and will carry a current indefinitely without heating up
Examples of superconductive materials used as electromagnets Correct Answer alloy of
niobium and titanium at certain temperature
What temperature is needed for superconductive electromagnetism? Correct Answer 4
kelvin
What are used to cool superconductive materials that are used in MRI electromagnets?
Correct Answer helium or nitrogen
What is the field strength of superconducting electromagnets? Correct Answer 14T
What are the safety considerations associated with MRI? Correct Answer biological
effects, projectile hazards and compatibility of medical devices
What is the effect of MRI on nerves and muscles? Correct Answer can stimulate
peripheral nerve and muscles
What is the hazard that is associated with radiofrequency magnetic fields? Correct
Answer induced current burns and contact burns
Why should all devices brought around the MRI at ANYTIME be compatible? Correct
Answer the MRI machine is always on and projectile hazard could occur
How does the quench MRI safety mechanism work? Correct Answer helium is vented
from the cryostat around the windings
What is the effect of quenching on the superconductive electromagnet? Correct Answer
resistance increases and causes the current to stop flowing and magnetic field is lost
When is quenching carried out? Correct Answer life threatening situations
Questions with 100% Correct Answers
What provides the external magnetic field in MRI? Correct Answer The MRI machine
The patient is said to be ____ by the MRI machine Correct Answer magnetised
Where does the radiofrequency pulse come from? Correct Answer the MRI machine
What does the radiofrequency pulse provided by the MRI machine do? Correct Answer
allows patient photons to spine in phase with each other
Where are the coils used to the detect the signal placed? Correct Answer on the MRI
table
How are MRI signals detected Correct Answer Faradays law of electromagnetic
induction
Faradays law of electromagnetic induction states that Correct Answer if a conductive
loop is placed in an
Area of moving magnetic field, a current will be induced.
Magnetic field strength is measured in... Correct Answer Tesla (T)
1 Tesla is Correct Answer 10,000 Gauss (G)
Many MRI machines have strength ranging from Correct Answer 0.5T to 3T
Research MRI machines commonly have magnetic of what strength ? Correct Answer
7T
Types of magnets used in MRI Correct Answer permanent magnets and electromagnets
What metals will retain their magnetism once magnetised? Correct Answer iron, cobalt
and nickel
Metals used as permanent magnets are those that... Correct Answer can retain their
magnetism once magnetised
What direction does the magnetic field run in permanent magnet MRI machines?
Correct Answer vertically
If a current is passed through a long straight wire, .... Correct Answer a magnetic field is
produced around the wire
, The strength of magnetic field aroudn a long straight wire is proportional to.... Correct
Answer the amount of current
What is a solenoid magnet? Correct Answer an electromagnet that uses a loop of wire
The strength of the magnetic field of a solenoid magnet is proportional to Correct
Answer the amount of loops and strength of current
The magnetic field strength of electromagnets used in MRI is Correct Answer 0.2T to
0.3T
What is a superconductive material? Correct Answer a material that has no resistance
and will carry a current indefinitely without heating up
Examples of superconductive materials used as electromagnets Correct Answer alloy of
niobium and titanium at certain temperature
What temperature is needed for superconductive electromagnetism? Correct Answer 4
kelvin
What are used to cool superconductive materials that are used in MRI electromagnets?
Correct Answer helium or nitrogen
What is the field strength of superconducting electromagnets? Correct Answer 14T
What are the safety considerations associated with MRI? Correct Answer biological
effects, projectile hazards and compatibility of medical devices
What is the effect of MRI on nerves and muscles? Correct Answer can stimulate
peripheral nerve and muscles
What is the hazard that is associated with radiofrequency magnetic fields? Correct
Answer induced current burns and contact burns
Why should all devices brought around the MRI at ANYTIME be compatible? Correct
Answer the MRI machine is always on and projectile hazard could occur
How does the quench MRI safety mechanism work? Correct Answer helium is vented
from the cryostat around the windings
What is the effect of quenching on the superconductive electromagnet? Correct Answer
resistance increases and causes the current to stop flowing and magnetic field is lost
When is quenching carried out? Correct Answer life threatening situations
