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MRSO Exam mark Questions & answers
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MRSO: Exam markWhich of the following describe when a non-ferrous object is repulsed by static
magnetic field?
a. Fourier transformation
b. Lenz's force
c. Ohm's law
d. Larmor equation - ANS-b. Lenz's force
What is the FDA SAR limit for the whole body in first level controlled operating mode?
a. 8 W/kg for 15 mins
b. 4 W/kg for 15 mins
c. 3 W/kg for 10 mins
d. 7 W/kg for 20 mins - ANS-b. 4 W/kg for 15 mins
Gadolinium contains what kind of magnetism?
a. Diamagnetic
b. Paramagnetic
c. Ferromagnetic
d. Super paramagnetic - ANS-b. Paramagnetic
Where will peripheral nerve stimulation be the strongest?
a. Further away from isocenter in the gantry
b. At the level of the table when it is advanced
c. At isocenter
d. Outside the gantry near the 5 gauss line - ANS-a. Further away from the isocenter in
the gantry
What is the name for the direction of the vector of the static magnetic field?
a. Inverse field
b. Equilibrium
c. B0
d. B1 - ANS-c. B0
An object that produces a weakly repulsive force in the presence of a strong magnetic
field is called what?
,a. Superparamagnetic
b. Ferromagnetic
c. Diamagnetic
d. Paramagnetic - ANS-c. Diamagnetic
The gradient coils are responsible for which of the following? Select all that apply.
a. Heating
b. Rotational force
c. Translational force
d. Magnetohydrodynamic effect
e. Noise
f. Peripheral nerve stimulation - ANS-e. Noise
f. Peripheral nerve stimulation
Why is magnetic shielding used in an MR unit?
a. To reduce heating
b. To reduce the e-fields
c. To maintain field homogeneity
d. To limit the fringe field - ANS-d. To limit the fringe field
Contrast media will do what to our tissue?
a. Shorten T1 relaxation times
b. Shorten T1 & T2 relaxation times
c. Increase T2 relaxation times and decrease T1 relaxation times
d. Shorten T2 relaxation times - ANS-b. Shorten T1 & T2 relaxation times
As blood flows through a vessel, currents can be induced. The degree of this is called?
a. Magnetophosphenes
b. Flow potential
c. Translational forces
d. Fringe field - ANS-b. Flow potential
The T-wave in the cardiac cycle represents what?
a. Heart repolarization
b. Heart depolarization
c. None of the choices
,d. Arrhythmia - ANS-a. Heart repolarization
NSF is caused by what?
a. When the patient is allergic to gad contrast
b. When gad ion is excreted by the liver
c. When gad ion is excreted from the body quickly
d. When a gad ion breaks free from the ligand and remains in the body - ANS-d. When
a gad ion breaks free from the ligand and remains in the body
What pulse sequence will produce the most patient heating?
a. Gradient echo
b. Conventional spin echo
c. Inverse recovery sequence
d. Single shot fast spin echo - ANS-d. Single shot fast spin echo
The allowable maximum strength of the gradient coils is called?
a. Spacial gradient
b. Rise time
c. Slew rate
d. Maximum gradient peak - ANS-d. Maximum gradient peak
Using a headset and earplugs will reduce noise by how much?
a. 50 dB
b. By the NRR of the headset + NRR of earplugs
c. By the NRR of the headset
d. By the NRR of the headset + NRR of earplugs divided by 2 - ANS-b. By the NRR of
the headset + NRR of earplugs
Time-varying gradient magnetic fields are measured in which of the following?
a. W/kg
b. Tesla
c. dB/dt
d. dB/dx - ANS-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...?
, a. It touches tissues
b. None of the choices
c. It is in very close proximity to tissue
d. It doesn't touch tissue - ANS-c. It is in very close proximity to tissue
The FDA limits SAR in the head to what?
a. 3.2 W/kg for 10 min
b. 8 W/kg for 20 min
c. 10 W/kg for 15 min
d. 4 W/kg for 15 min - ANS-a. 3.2 W/kg for 10 min
The gradient coils are used for what in MRI?
a. Tilting nuclei in to the transverse plane
b. Spacial encoding
c. Resonance production
d. Aligning nuclei to a vector - ANS-b. Spatial encoding
Passive shield is performed how?
a. A magnetically conductive material surrounds the MR unit and this shapes and
contains the magnetic field
b. Bricks permanent magnets are stacked around the MR unit to contain the fringe field
c. Nothing is used with passive shielding
d. A coil of wire in the MR unit has a current running through it which produces a
magnetic field opposing the B0 - ANS-a. A magnetically conductive material surrounds
the MR unit and this shapes and contains the magnetic field
The speed that the gradient coils can turn on and off is called what?
a. Maximum gradient peak
b. Rise time
c. Spatial gradient
d. Slew rate - ANS-d. Slew rate
The speed that it takes a gradient coil to reach a maximum strength is called what?
a. Maximum gradient peak
b. Rise time
c. Spatial gradient
d. Slew rate - ANS-b. Rise time
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