Part D: Instrumentation Flashcards
1
Q
- Magnetic fields associated with MR imaging systems include the:
- Static magnetic field (B₀)
- RF (radiofrequency) field (B₁)
- Gradient field
- Gantry field
a. 1 only
b. 1 and 2 only
c. 1, 2, and 3 only
d. 1, 2, 3 and 4
A
c. 1, 2, and 3 only
2
Q
- The MR system component that produces the B₀ field is the:
a. Main magnet
b. Radiofrequency system
c. Gradient system
d. Shim system
A
a. Main magnet
3
Q
- The MR system component that produces the B₁ field is the:
a. Main magnet
b. Radiofrequency system
c. Gradient system
d. Shim system
A
b. Radiofrequency system
4
Q
- There are various types of magnets that can be used for MR images: These include:
- Permanent magnet
- Resistive magnet
- Hybrid magnet
- Superconducting magnet
a. 1 only
b. 1 and 2 only
c. 1, 2 and 3 only
d. 1, 2, 3 and 4
A
d. 1, 2, 3 and 4
5
Q
- The MR system component that provides a means for alignment (magnetisation of proton spins) is the:
a. Main magnet
b. Radiofrequency system
c. Gradient system
d. Shim system
A
a. Main magnet
6
Q
- The MR system component that provides a means for excitation is the:
a. Main magnet
b. Radiofrequency system
c. Gradient system
d. Shim system
A
b. Radiofrequency system
7
Q
- The MR system component that provides a means for spatial encoding is the:
a. Main magnet
b. Radiofrequency system
c. Gradient system
d. Shim system
A
c. Gradient system
8
Q
- The liquids cryogen(s) commonly used to maintain the magnet coil at superconducting temperature is (are):
a. Helium
b. Hydrogen
c. Nitrogen
d. a and c
A
a. Helium
9
Q
- Some systems use only one cryogen. In such systems, the cryogen is:
a. Nitrogen
b. Hydrogen
c. Helium
d. Oxygen
A
c. Helium
10
Q
- Faraday’s law of induction states that if a loop of wire is moved through a magnetic field, _______ will be created in the wire.
a. A magnetic wave
b. A voltage
c. Torque
d. Resonance
A
b. A voltage
11
Q
- The equation associated with Faraday’s law of induction is:
a. W/kg
b. ω0= B₀γ
c. ∆B/ ∆T= ∆V
d. Ppm
A
c. ∆B/ ∆T= ∆V
12
Q
- According to Faraday’s law of induction, the amount of current produced in a loop of wire moving through a magnetic field is proportional to the:
a. Length of the wire
b. Strength of the magnetic field
c. Spin density of the wire
d. Time it takes for the magnetic field to reach full potential
A
b. Strength of the magnetic field
13
Q
- In a typical superconducting (cylindrical bore) magnet, the direction of the magnetic field is:
a. Vertical
b. Horizontal
c. Around the flux lines
d. Hard to measure
A
b. Horizontal
14
Q
- The direction of the magnetic field in a typical permanent magnet is:
a. Vertical
b. Horizontal
c. Around the flux lines
d. Hard to measure
A
a. Vertical
15
Q
- To maintain the magnetic fields of a resistive magnet, which of the following should be applied to the magnet coils?
a. Water
b. Heat
c. Current
d. Cooling
A
c. Current
16
Q
- Magnetic field strength is measured in units of Tesla (T) and Gauss (G) whereby 1T equals:
a. 1 G
b. 1 000 G
c. 10 000 G
d. 100 000 G
A
c. 10 000 G
17
Q
- 1.5T equals:
a. 10 000 G
b. 15 000 G
c. 30 000 G
d. 3 000 G
A
b. 15 000 G
18
Q
- In a superconducting magnet, the magnetic field strength is increased by increasing the:
a. Amount of cryogens
b. Temperature
c. Internal pressure
d. Turns of wire
A
d. Turns of wire
19
Q
- In a solenoid superconducting magnet, the direction of current flow affects the:
a. Strength of the magnetic field
b. Direction of the magnetic field
c. Intensity of the magnetic field
d. Homogeneity of the magnetic field
A
b. Direction of the magnetic field
20
Q
- Permanent magnets with a vertical magnetic field use surface colds that are:
a. Solenoids
b. Linear
c. Quadrature
d. Flat
A
a. Solenoids
21
Q
- The transmit bandwidth of the RF pulse affects:
a. Spatial resolution
b. Slice thickness
c. Image contrast
d. a and b
A
d. a and b
22
Q
- In order to create a thin slice thickness, a ______ is used.
- Steep slice selection gradient
- High amplitude slice selection gradient
- Narrow transmit bandwidth (tBW)
- Narrow receiver bandwidth (rBW)
a. 1 only
b. 1 and 2 only
c. 1, 2 and 3 only
d. 1, 2, 3 and 4
A
c. 1, 2 and 3 only
23
Q
- The receiver bandwidth affects:
a. Chemical shift artifact
b. Slice thickness resolution
c. Signal-to-noise ratio (SNR)
d. a and c
A
d. a and c
24
Q
- If a coil is improperly tuned, it will result in:
a. A decrease in SNR
b. A reduction in voxel size
c. Patients burns
d. Resonance artifacts
A
a. A decrease in SNR
25
Q
- The gradient magnetic fields are:
a. Always on
b. Superimposed over the main magnetic field
c. Used for contrast control
d. Controlled by RF pulses
A
b. Superimposed over the main magnetic field
26
Q
- The timing of RF pulses during an MR pulse sequence:
a. Controls image contrast
b. Spatially encodes the data
c. Shims the static magnetic field
d. a and b
A
a. Controls image contrast
27
Q
- The B1 magnetic field produced by a:
a. Gradient coil
b. Shim coil
c. Radiofrequency coil
d. Magnet coil
A
c. Radiofrequency coil
28
Q
- In an MRI system that uses shim coils, B₀ homogeneity is adjusted by:
a. Changing current in the shim coil
b. Adding metal to different coils within the shim coil
c. Adding current to the gradient coils
d. Turning the shim coil off and on very rapidly
A
a. Changing current in the shim coil
29
Q
- Shimming the MRI is performed by all of the following EXCEPT:
a. Changing current in the shim coil
b. Adding metal to different coils within the shim coil
c. Adding current to the gradient coils
d. Turning the shim coil off and on very rapidly
A
d. Turning the shim coil off and on very rapidly
30
Q
- Gradient strength (aplitude) is measured in units of:
- mT/M
- G/cm
- T/m/s
- μs
- %
a. 1 only
b. 1 and 2 only
c. 3 only
d. 4 only
e. 5 only
A
b. 1 and 2 only
31
Q
- Gradient speed (rise time) is measured in units of:
- mT/M
- G/cm
- T/m/s
- μs
- %
a. 1 only
b. 1 and 2 only
c. 3 only
d. 4 only
e. 5 only
A
d. 4 only
32
Q
- Gradient speed (rise time) and strength (amplitude) is measured in units of:
- mT/M
- G/cm
- T/m/s
- μs
- %
a. 1 only
b. 1 and 2 only
c. 3 only
d. 4 only
e. 5 only
A
c. 3 only
33
Q
- The amount of time that a gradient is ‘permitted’ to work is known as the duty cycle and is measured in units of:
- mT/M
- G/cm
- T/m/s
- μs
- %
a. 1 only
b. 1 and 2 only
c. 3 only
d. 4 only
e. 5 only
A
e. 5 only
34
Q
- The gradient strength is measured in units of:
a. Amplitude
b. Slew rate
c. Duty cycle
d. Rise time
A
a. Amplitude
35
Q
- Th gradient characteristic that reflects both strength and speed is known as the:
a. Amplitude
b. Slew rate
c. Duty cycle
d. Rise time
A
b. Slew rate
36
Q
- Gradients can work for a period of time known as the:
a. Amplitude
b. Slew rate
c. Duty cycle
d. Rise time
A
c. Duty cycle
37
Q
- Gradient characteristic for speed is known as the:
a. Amplitude
b. Slew rate
c. Duty cycle
d. Rise time
A
d. Rise time
38
Q
- RF coil configuration include:
- Linear
- Quadrature
- Phase array
- Helmholtz
- Multichannel
a. 1 only
b. 1 and 2 only
c. 1, 2, and 3 only
d. 1, 2, 3 and 4 only
e. 1, 2, 3, 4, and 5
A
e. 1, 2, 3, 4, nd 5
39
Q
- RF coil configurations that use multiple coils with one single receiver include:
- Linear
- Quadrature
- Phase array
- Helmholtz
- Multichannel
a. 1 only
b. 1 and 2 only
c. 3 and 5 only
d. 4 only
A
d. 4 only
40
Q
- RF coil configurations that use multiple coils with multiple receivers include:
- Linear
- Quadrature
- Phase array
- Helmholtz
- Multichannel
a. 1 only
b. 1 and 2 only
c. 3 and 5 only
d. 4 only
A
c. 3 and 5 only
41
Q
- The sensitivity profile for a given coil is known as the:
a. Pulse profile
b. Spectrum
c. FID
d. Echo
A
a. Pulse profile
42
Q
- RF coil configurations that use coilds whereby the coil is confiured with wires (or electronic components) that are perpendicular to one naother are known as:
- Linear
- Quadrature
- Phase array
- Helmholtz
- Multichannel
a. 1 and 2 only
b. 2 only
c. 3 and 5 only
d. 4 only
A
b. 2 only
