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MRSO: EXAM MARK | QUESTIONS &
100 % VERIFIED ANSWERS | LATEST
UPDATE | GRADED A+
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 Correct Answer: 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 Correct Answer: b. 4 W/kg for 15 mins
Gadolinium contains what kind of magnetism? a. Diamagnetic b. Paramagnetic c. Ferromagnetic d. Super paramagnetic Correct Answer: 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 Correct Answer: 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. B d. B Correct Answer: c. B
d. To limit the fringe field Correct Answer: 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 Correct Answer: 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 Correct Answer: 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 Correct Answer: 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 Correct Answer: 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 Correct Answer: d. Single shot fast spin echo The allowable maximum strength of the gradient coils is called? a. Spacial gradient b. Rise time
a. It touches tissues b. None of the choices c. It is in very close proximity to tissue d. It doesn't touch tissue Correct Answer: 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 Correct Answer: 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 Correct Answer: 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 B Correct Answer: 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 Correct Answer: 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 Correct Answer: b. Rise time
The IEC 60601- 2 - 33 normal operating mode is __________ the energy requirements limited in the first level controlled operating mode. a. Half b. Triple c. Double d. Not comparable to Correct Answer: a. Half An object that produces a weakly attractive force in the presence of a strong magnetic field is called what? a. Superparamagnetic b. Ferromagnetic c. Diamagnetic d. Paramagnetic Correct Answer: d. Paramagnetic The noise heard in MRI is caused by which of the following? a. Lorentz force b. The antenna effect c. Larmor force d. Ohm's force
Correct Answer: a. Lorentz force What is the purpose of cryogen? a. Reduce the heating produced in the MRI unit during each acquisition b. Eliminate electrical current resistance in the coils of wire that produce the static magnetic field c. Reduce the overall noise produced during acquisition d. Allow the MRI unit to function at the fast speeds necessary to achieve an MRI image Correct Answer: b. Eliminate electrical current resistance in the coils of wire that produce the static magnetic field The transmission of radiofrequency waves will cause what? a. Peripheral nerve stimulation b. Magnetohydrodynamic effect c. Patient heating d. Vertigo Correct Answer: c. Patient heating What are the patient limits for the time-varying gradient coils? a. To the comfort of our patient b. 10 G/sec c. 35 G/sec d. To the point a patient has a seizure
An energy deposition mode set to NORMAL OPERATION MODE will allow heating in a patient to what? a. 1 degree Celsius b. 0.5 degrees Celsius c. 3 degrees Celsius d. 2 degrees Celsius Correct Answer: b. 0.5 degrees Celsius Where are the gradient coils found? a. Under the patient b. At the control panel on the MR unit c. In Zone III d. Surrounding the patient Correct Answer: d. Surrounding the patient What is the purpose of resonance? a. To align nuclei with the B b. To slow down the precessional frequency of nuclei c. Resonance is not used in MRI d. To tilt nuclei of interest away from the B Correct Answer: d. To tilt nuclei of interest away from the B Which of the following is measured in milliseconds?
a. The slew rate b. The rise time c. Maximum gradient peak d. Spatial gradient Correct Answer: b. The rise time The near field effects of the radiofrequency energy can cause what kind of issues? a. Reflective burning b. Missile effect c. Proximity burning d. Resonant burning Correct Answer: c. Proximity burning When can heating occur in a wire? a. In small round metal objects b. When the transmitted frequency matches or is a multiple of the length of the wire c. Only in ferrous objects d. When objects get smaller Correct Answer: b. When the transmitted frequency matches or is a multiple of the length of the wire
Which of the following describes the total dose of energy that a tissue receives during an entire exam? a. Specific energy dose b. Specific absorption equivalent c. Overall concentration dose d. Total voltage absorbed Correct Answer: a. Specific energy dose What is the name of the gradient coil used to produce sagittal and coronal images? a. Transverse coil b. Golay coil c. Maxwell coil d. Receiver coil Correct Answer: b. Golay coil ("saddle coil") Which of the following is able to handle the most RF heating? a. elderly b. adult c. obese adult d. neonate Correct Answer: d. neonate
Which of the following techniques can be used to increase the echo spacing? Select all that apply. a. Increase the TR b. Decrease receiving bandwidth c. Increase receiving bandwidth d. Use a receive only coil e. Increase field of view f. Increase flip angle Correct Answer: b, e Decreasing the receiving bandwidth will be lengthening the sample time. This may force us to increase our TE as well as the TR. Increasing the field of view will also allow for longer echo spacing. The differences in magnetic field strength as you approach the MRI unit is termed what? a. Spatial magnetic gradient b. Gauss line c. RF energy d. Gradient coils Correct Answer: a. Spatial magnetic gradient
c. 40 G/cm d. 400 G/cm Correct Answer: d. 400 G/cm 1T = 10,000 G 1m = 100 cm Therefore, 1 T/m=10,000G/100cm This means that 1 T/m=100 G/cm How do we calculate the maximal spatial gradient? a. dB/dx * B b. dB/dt * W/kg c. W/kg d. B Correct Answer: a. dB/dx * B Which of the following is true of a gad contrast osmolarity? a. Less than blood b. Greater than blood c. Less than water d. Equal to blood Correct Answer: b. Greater than blood (and greater than water)
Which of the following is true if we increase the field of view from 200mm to 400mm? a. We reduce patient heating b. We use a stronger time-varying gradient magnetic field c. We use a weak time-varying gradient magnetic field d. We increase the patient heating Correct Answer: c. We use a weak time-varying magnetic field. Larger field of views will produce lower resolution exams. The size of the field of view is dependent on the frequency encoding gradient coil. When we increase the field of view, we decrease the amplitude of our gradient coil. When a T1 weighted image is taken of a vial of gad contrast, it will appear how? a. Bright b. Dark c. Gray d. Blue Correct Answer: b. Dark Active shield is performed how?
