Which of the following is an advantage of a permanent magnet MRI system
Very heavy
Low operating costs
Fixed field strength
Limited field strength
Which of the following types of MRI magnet is known as the Classical electromagnet
Resistive magnet
Superconducting magnet
Permanent magnet
Distractive magnet
Which of the following is a disadvantage of a resistive magnet MRI system
Easy coil maintenance
Low cost
High power consumption
None of the above
The type of MRI magnet that is produced by cooling a current down to 4 degrees Kelvin is known as a
The type of MRI magnet that allows the highest field strengths is a
Iron core magnet
Coils used to correct imperfections in the magnetic field are known as
RF coils
Surface coils
Gradient coils
Shim coils
The type of magnet that is produced by permanently magnetizing a ferromagnetic substance is known as a
Electromagnet
In clinical MRI, permanent magnets can be produced to operate up to what field strength
0.3 tesla
0.5 tesla
1.0 tesla
1.5 tesla
Which of the following is a disadvantage of using a permanent magnet in clinical MRI
Low fringe field
Low operating cost
Low field strength
Low fringe field & Low field strength
Which of the following materials is most commonly used to produce a permanent magnet
Niobium-Titanium alloy
Copper-Gadolinium alloy
Aluminum-Nickel-Cobalt alloy
Iron
The type of magnet that is produced by passing an electrical current through a conductor is known as a
Resistive magnet & Electromagnet
The rule that is used to determine the direction of the magnetic field in an electromagnet is known as
Ohm's Law
Right hand thumb rule
Left hand thumb rule
In clinical MRI, resistive magnets usually operate at what field strength
Between 0.15 - 0.25 tesla
Between 0.5 - 1.5 tesla
Between 1.5 - 2 tesla
Over 2 tesla
Which of the following is an advantage of using a resistive magnet for clinical MRI
Low capital cost
The law that is used to determine the amount of resistance in a conductor is known as
Newton's Law
Faraday's Law
Murphy's Law
The type o f magnet that is produced by removing resistance from a conductive wire is known as
Reactive magnet
The wire used to create the main magnetic field in a superconducting magnet is known as
Aluminum-Tiobium
Iron sulfite
Copper-tungsten
Niobium-Titanium
The external magnetic field in a superconducting magnet is said to be what type of magnetic field
Static
Kinetic
Gradient
Resistive
The wire used in the main magnetic field of a superconducting magnet has its resistance removed by cooling it to a temperature of
-452 degrees Fahrenheit
0 degrees Celsius
269 degrees Kelvin
The liquids used to cool the wire in the main magnetic field of a superconducting magnet are known as
Neon gases
Plasma
Cryogens
The specific liquids used to maintain low temperatures in the superconducting wire are
Titanium and Niobium
Hydrogen and Neon
Halon and Oxygen
Helium and Nitrogen
The device used to store and transport cryogenic liquids is known as a
Thermos
Dewar
Barrel
In a superconducting magnet, the sudden loss of superconductivity is known as a
Squelch
Slouch
Screech
Quench
In an MRI system, the magnetic field that extends outside the bore of the magnet is known as the
Extended field
Outer field
Fringe field
In field
In clinical MRI, superconducting magnets usually operate at field strengths from
0.15 to 0.3 tesla
0.5 to 2.0 tesla
2.5 to 4.0 tesla
Over 4 tesla
In clinical MRI, which of the following is an advantage of using a superconducting magnet
High field strength
Shorter scan times
Low power consumption
All of the above
In clinical MRI, which of the following is a disadvantage of using a superconducting magnet
High capital costs
High fringe field
High cryogenic costs
The method used to contain the main magnetic field within the scan room is known as
Shimming
Shielding
Fringing
The method of MRI field containment that uses steel lining in the walls of the magnetic room is known as
Active shimming
Passive shielding
Active shielding
Passive shimming
The method of MRI field containment that uses additional magnets outside the cryogenic area of the magnet is known as
The process of adjusting coils to improve the homogeneity of the external magnetic field is known as
Strengthening
Each shim coil requires its own power supply
True
False
The type of shimming that is achieved by placing a ferrous material around the main magnet is known as
The type of shimming that is achieved by adjusting the electrical current in specialized coils is known as
The homogeneity of the external magnetic field is measured in what type of unit
Tesla per cm
Part per million (ppm)
Gauss per meter
Megahertz
In clinical MRI, the homogeneity of the magnet should be at least
1 tesla per cm
10 parts per million
0.5 gauss per meter
32 magahertz
The type of coils used to change the strength of the magnetic field inside the bore of the magnet are known as
In a gradient coil, the amplitude of the gradient slope is determined by what factor
The amount of current passing through the coil
Transmit bandwidth
The strength of the external magnetic field
How many gradient coils are there in a clinical MRI system
1 pair
2 pairs
3 pairs
4 pairs
Gradient strength is measured in what form of unit
Gauss per centimeter
Militesla per meter
Gauss per centimeter & Militesla per meter
The time it takes for a gradient coil to reach its peak strength is known as its
Repetition time
Echo time
Rise time
Inversion time
Coils that are used to transmit and receive radio frequencies are known as
The type of RF coil that encompasses the entire anatomy to be scanned is known as
Surface coil
Phased array coil
Volume coil
Gradient coil
The type of RF coil configuration that uses a pair of coils perpendicular to each other to transmit and receive signal is known as a
Quadrature coil
Shim coil
The type of RF coil configuration that uses a series of independent coils to create one image is known as a
The type of RF coil configuration that is used to image anatomical structures close to the surface of the patient is known as a
Mutual induction between the RF transmitter and the RF receiver is known as
Isolation
Deisolation
Coupling
Decoupling
Isolating the RF transmitter from the RF receiver is known as
The computer that performs the complex calculations necessary to reconstruct MRI images is known as the
Array processor
RF amplifier
Gradient amplifier
Shim cabinet
The device in the MRI system that supplies power to the gradient coils is known as the
The device in the MRI system that supplies power to the RF transmitter coils is known as the
Prior to each scan, the process of prescanning performs which type of calibration
Adjusts the transmit gain
Adjusts the receive attenuation
Sets the center frequency
The calibration of transmit gain during the prescan process determines which factor
RF output necessary to produce a 90 degree flip angle
The exact resonant frequency
The necessary amount of signal needed to create an image
The process during the prescan that determines the amount of signal that is received is known as
Center frequency adjustment
Transmit gain adjustment
Receive attenuation adjustment
Impedance matching
The process during prescan that fine tunes the resonant frequency is known as
How many miliseconds are there in a minute
60
600
6,000
60,000