MRSO Exam 1 Questions with Complete Solutions.docx

MRSO Exam 1 Questions with Complete S The control room is found where? a. Zone I b. Zone II c. Zone III d. Zone IV - Answer-C. Zone III 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 - Answer-b. Lenz's force Which of the following are recommended by the ACR Guidance document in MR safety 2013 in proper scanning of a patient? I.Metal detector II.Ferromagnetic detection system III. Written screening sheet IV. Patient gown a. I, III, IV b. I, II, III, IV c. II, III, IV d. III - Answer-c. II, III, IV 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 - Answer-b. 4 W/kg for 15 mins Gadolinium contains what kind of magnetism? a. Diamagnetic b. Paramagnetic c. Ferromagnetic d. Super paramagnetic - Answer-b. Paramagnetic Which of the following is true of Zone IV? Select all that apply. a. This area should be monitored by a level 2 MR personnel b. Should be noted with signage c. Contain metal detectors for implant identification d. No unsafe implants may cross the 5-gauss unless the implant is researched and analyzed for risk - Answer-a, b, d 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 - Answer-a. Further away from the isocenter in the gantry A patient is advanced in the MRI scanner very quickly and experiences a sensation of flashing lights in their visual field. What are they experiencing? a. Nystagmus b. Heating c. Magnetophosphenes d. Magnetohydrodynamic effect - Answer-c. Magnetophosphenes What is the name for the direction of the vector of the static magnetic field? a. Inverse field b. Equilibrium c. B0 d. B1 - Answer-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 - Answer-c. Diamagnetic What are the risks associated with translational force? a. Missile effect b. Proximity heating c. Antenna effect d. Peripheral nerve stimulation - Answer-a. Missile effect Which of the following are recommended by the ACR guidance document in MR safety 2013 in proper scanning of a patient? a.Patient gown b.Written screening sheet c. Metal detector d. Ferromagnetic detection system - Answer- 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 - Answer-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 - Answer-d. To limit the fringe field What document has established guidelines for MRI safety that are followed today? a. ACR white paper MRI safety b.HIPPA c.FDA guidelines of MRI d.OSHA - Answer-a. ACR white paper MRI safety Pain at the injection site when gad contrast is administered is considered what? a.Anaphylaxis b.A non-allergic reaction c. None of the choices d. Allergic reaction - Answer-b. a non-allergic reaction Normal kidneys should excrete all gad from a patient how quickly? a. 24 hours b. 6 hours c. 12 hours d. 32 hours - Answer-a. 24 hours 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 - Answer-b. Shorten T1 & T2 relaxation times Resonance occurs when: a. The patient is placed in isocenter and only experiences the static magnetic field. b. The radiofrequencies transmitted are different than the precessional speed of hydrogen c. The radiofrequencies transmitted match the precessional speed of hydrogen d. The radiofrequency is transmitted at 42.6 MHz - Answer-c. The radiofrequencies transmitted match the precessional speed of hydrogen 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 - Answer-b. Flow potential Why are metal detectors not recommended in MRI screening? a. They have varied sensitivity b. They are operator skill dependent c. All of the choices d. They cannot detect small fragments well - Answer-c. All of the choices The T-wave in the cardiac cycle represents what? a. Heart repolarization b. Heart depolarization c. None of the choices d. Arrhythmia - 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 - Answer-d. When a gad ion breaks free from the ligand and remains in the body Which of the following require minimal MR safety training? a. Level 2 MR personnel b. Level 1 MR personnel c. Non-MR personnel d. Patient - Answer-b. Level 1 MR personnel 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 - Answer-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 - Answer-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 - Answer-b. By the NRR of the headset + NRR of earplugs Wires and leads can produce heat because they are? a. Magnetic b.Diamagnetic c.Electrically conductive d.Reactive - Answer-c. Electrically conductive Time-varying gradient magnetic fields are measured in which of the following? a. W/kg b. Tesla c. dB/dt d. dB/dx - Answer-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 - 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 - 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 - Answer-b. Spatial encoding Which of the following are considered non-allergic reactions to the gad contrast? Select all that apply. a. Pain at injection site b. Emesis c. Headache d. Hives - Answer-a,b,c 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 - Answer-a. A magnetically conductive material surrounds the MR unit and this shapes and contains the magnetic field An object that retains a magnetic field as it is removed from a strong magnetic field is called what? a. Paramagnetic b. Ferromagnetic c. Diamagnetic d. Superparamagnetic - Answer-b. Ferromagnetic 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 - 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 - Answer-b. Rise time A patient undergoing an MRI exam is given an icepack to reduce heat. Which of these methods is the patient using to regulate their increased heating? a. Convection b. Conduction c. Radiation d. Evaporation - Answer-b. Conduction Which of the following are units of measurement for static magnetic fields? a. Tesla and gauss b. Tesla c. Gauss d. Decibels - Answer-a. Tesla & gauss What is the purpose of the static magnetic field? a. To align hydrogen nuclei parallel and anti-parallel to B0 b. To reverse the spin of the hydrogen nuclei c. To produce currents in tissues containing hydrogen nuclei d. To measure the movement of hydrogen nuclei - Answer-a. To align hydrogen nuclei parallel and anti-parallel to B0 Induction of electrical current in our patient from changing magnetic fields can be described by which of the following? a.Ohm's law b.Fourier equation c.Faraday's law of induction d.Larmor equation - Answer-c. Faraday's law of induction A patient will change into a gown in this location. a. Zone I b. Zone IV c. Zone II d. Zone III - Answer-c. Zone II