Topic 2 Instrumentation and Equipment

What is the primary function of the shim system in an MRI scanner?

• To generate radio frequency pulses

• To receive signals from the RF coils

• To enhance the magnetic field's homogeneity

• To provide power to the gradient coils

What type of shielding uses large steel plates to reroute the fringe field?

• Active shielding

• Dynamic shielding

• Gradient shielding

• Passive shielding

Which type of shimming uses electromagnets to adjust the magnetic field?

• Passive shimming

• Active shimming

• Dynamic shimming

• Static shimming

What is the main purpose of the gradient coil in an MRI system?

• To locate the origin of the MRI signal

• To enhance image resolution

• To generate radio frequency pulses

• To provide power to the RF coils

What is the function of the gradient amplifiers?

• To supply power to the RF coils

• To amplify the current for the gradient coils

• To demodulate the received signals

• To control the magnetic field strength

Which type of RF coil is closest to the patient?

• Body coil

• Gradient coil

• Surface coil

• Volume coil

What is the primary disadvantage of passive shielding?

• It is heavy and very expensive

• It is inexpensive

• It is lightweight

• It requires no maintenance

What does the term 'duty cycle' refer to in gradient characteristics?

• The frequency of the RF pulses

• The duration of the gradient pulse

• The amplitude of the gradient slope

• The efficiency of the RF coil

What is the purpose of the RF transmission system in an MRI scanner?

• To receive signals from the patient

• To generate and transmit electromagnetic radiation pulses

• To enhance the magnetic field

• To control the gradient coils

Which type of shimming is described as adjusting for large changes of inhomogeneity?

• Passive shimming

• Active shimming

• Dynamic shimming

• Gradient offset shimming