Welcome to your MRI - A Name [The magnet's ability to attract and repel objects was first described by which of the following people?] Alexander Necham Lucretius Cerus Hoang-ti None of the above None . [The computer that performs the complex calculations necessary to reconstruct MRI images is known as the _____.] Array processor RF amplifier Gradient amplifier Shim cabinet None . [The condition that occurs in a gradient echo pulse sequence when the TR is shorter than the T 1 and T2 relaxation times of tissue is known as ______. ] Chemical shift Steady state Frequency shift Phase shift None . [The calibration of transmit gain during the prescan process determines which factor?] RF output necessary to produce a 90 degree flip angle The exact resonant frequency The necessary amount of signal needed to create an image None of the above None . [The signal created after applying a 90 degree RF pulse is known as a _______.] Gradient echo signal Spin echo signal Spin spin signal FID Signal None . [Which of the following is a method used in MRA to increase signal from vascular structures?] Gradient moment nulling Subtraction Bipolar gradient Both A and C None . [Which of the following is the equation that is used to determine precessional frequencies?] Wo=yBo Bo=yWo F= yBo Both A and C None . [The type of magnet that is produced by passing an electrical current through a conductor is known as a ________.] Permanent magnet Resistive magnet Electromagnet Both B and C None . [Proper patient screening should include which of the following?] The elimination of any loose metal objects and personal items The identification of any possible contraindications The identification of any biomedical implants All of the above None . [Materials reach their highest magnetic potential when their atoms are grouped in areas known as _______.] Regions Fields Fringes Domains None . [The device in the MRI system that supplies power to the gradient coils is known as the _____.] Array processor RF amplifier Gradient amplifier None of the above None . [Figure displays an example of what type of artifact?] Phase mismapping Aliasing Chemical shift Cross excitation None Comment . [A spin echo image with a long TR and a long TE is known as what type of image?] TI weighted image Proton density weighted image T2 weighted image Spin density weighted image None . [The type of magnet that is produced by removing resistance from a conductive wire is known as ________.] Resistive magnet Reactive magnet Permanent magnet Superconducting magnet None . [The magnitude of intra-voxel dephasing is dependent upon which factor(s)?] Degree of disruption in the flow Echo time Repetition time None of the above None . [Contrast agents that stay electrically neutral in water and do not separate into ions are said to be _____.] Hydrophilic Nonionic Ionic None of the above None . [Biological effects associated with exposure to radio frequency include which of the following?] Induction of electrical currents in tissue Heating due to tissue resistance Radiation poisoning Both A and B None . [Which of the following is a method used in MRA to suppress stationary tissue?] Tissue subtraction Tissue saturation Gradient moment nulling Both A and B None . [In conventional spin echo sequences, how many phase encoding steps must be selected to fill 128 lines of K space?] 64 128 192 256 None . [When the amplitude of the phase encoding gradient increases, the amount of phase shift along the gradient _______.] Increases Decreases Stays the same None of the above None . Time's up
