Revised MRSO: Exam |Question and Answers| 100% Correct Answers

Revised MRSO: Exam |Question and Answers| 100% Correct Answers Which 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