MRSO: Exam mark 209 Questions with Complete

MRSO: Exam mark 209 Questions with Complete

Solutions 100% Verified Which of the following describe when a non-ferrous object is repulsed by static magnetic field?

• Fourier transformation
• Lenz's force
• Ohm's law
• Larmor equation - Correct Answers b. Lenz's force

What is the FDA SAR limit for the whole body in first level controlled operating mode?

• 8 W/kg for 15 mins
• 4 W/kg for 15 mins
• 3 W/kg for 10 mins
• 7 W/kg for 20 mins - Correct Answers b. 4 W/kg for 15 mins

Gadolinium contains what kind of magnetism?

• Diamagnetic
• Paramagnetic
• Ferromagnetic
• Super paramagnetic - Correct Answers b. Paramagnetic

Where will peripheral nerve stimulation be the strongest?

• Further away from isocenter in the gantry
• At the level of the table when it is advanced
• At isocenter
• Outside the gantry near the 5 gauss line - Correct Answers a. Further away from the isocenter in

the gantry What is the name for the direction of the vector of the static magnetic field?

• Inverse field 1 / 4

• Equilibrium
• B0
• B1 - Correct Answers c. B0

An object that produces a weakly repulsive force in the presence of a strong magnetic field is called what?

• Superparamagnetic
• Ferromagnetic
• Diamagnetic
• Paramagnetic - Correct Answers c. Diamagnetic

The gradient coils are responsible for which of the following? Select all that apply.

• Heating
• Rotational force
• Translational force
• Magnetohydrodynamic effect
• Noise
• Peripheral nerve stimulation - Correct Answers e. Noise
• Peripheral nerve stimulation

Why is magnetic shielding used in an MR unit?

• To reduce heating
• To reduce the e-fields
• To maintain field homogeneity
• To limit the fringe field - Correct Answers d. To limit the fringe field

Contrast media will do what to our tissue?

• Shorten T1 relaxation times
• Shorten T1 & T2 relaxation times 2 / 4

• Increase T2 relaxation times and decrease T1 relaxation times
• Shorten T2 relaxation times - Correct Answers b. Shorten T1 & T2 relaxation times

As blood flows through a vessel, currents can be induced. The degree of this is called?

• Magnetophosphenes
• Flow potential
• Translational forces
• Fringe field - Correct Answers b. Flow potential

The T-wave in the cardiac cycle represents what?

• Heart repolarization
• Heart depolarization
• None of the choices
• Arrhythmia - Correct Answers a. Heart repolarization

NSF is caused by what?

• When the patient is allergic to gad contrast
• When gad ion is excreted by the liver
• When gad ion is excreted from the body quickly
• When a gad ion breaks free from the ligand and remains in the body - Correct Answers d. When a

gad ion breaks free from the ligand and remains in the body What pulse sequence will produce the most patient heating?

• Gradient echo
• Conventional spin echo
• Inverse recovery sequence
• Single shot fast spin echo - Correct Answers d. Single shot fast spin echo 3 / 4

The allowable maximum strength of the gradient coils is called?

• Spacial gradient
• Rise time
• Slew rate
• Maximum gradient peak - Correct Answers d. Maximum gradient peak

Using a headset and earplugs will reduce noise by how much?

• 50 dB
• By the NRR of the headset + NRR of earplugs
• By the NRR of the headset
• By the NRR of the headset + NRR of earplugs divided by 2 - Correct Answers b. By the NRR of the

headset + NRR of earplugs Time-varying gradient magnetic fields are measured in which of the following?

• W/kg
• Tesla
• dB/dt
• dB/dx - Correct Answers c. dB/dt

"d"=change in "B"=static field strength "t"=time Therefore this means that a change in static field strength over a change in time.Gad contrast will affect tissue when...?

• It touches tissues
• None of the choices
• It is in very close proximity to tissue
• It doesn't touch tissue - Correct Answers c. It is in very close proximity to tissue

The FDA limits SAR in the head to what?

• 3.2 W/kg for 10 min
• / 4