MRI chapter 1: Basic Principles Practice Test.

atom - correct answer a tiny element that is the basis for all things molecule - correct answer 2 or more atoms arranged together hydrogen - correct answer the most abundant atom in the body electron - correct answer negatively charged particles that spin around the nucleus nucleons - correct answer particles in the nucleus proton - correct answer positively charged element of the atomic nucleus neutron - correct answer neutral charged element of the atomic nucleus atomic number - correct answer sum of protons in the nucleus mass number - correct answer sum of protons and neutrons isotopes - correct answer same number of protons but different number of neutrons ions - correct answer atoms with excess or deficit of electrons angular momentum - correct answer the spin of MR active nuclei, which depends on the balance of the number of protons and neutrons in the nucleus MR active nuclei - correct answer nuclei that possess an odd mass number magnetic moment - correct answer denotes the direction of the north/south axis of a magnet and the amplitude of the magnetic field protium - correct answer isotope of hydrogen used in MRI. nucleus contains a single proton spin-up - correct answer the population of low-energy hydrogen nuclei that align their magnetic moments parallel to B0 spin down - correct answer the population of high-energy hydrogen nuclei that align their magnetic moments anti-parallel to B0 B0 - correct answer the main magnetic field measured in Tesla thermal equilibrium - correct answer assumes that patient's temperature is constant and therefore does not influence the thermal energy of hydrogen during the MR experiment Net Magnetization Vector (NMV) - correct answer the magnetic vector produced as a result of the alignment of excess hydrogen nuclei with B0 precession - correct answer the secondary spin of magnetic moments around B0 precessional path - correct answer the circular pathway of magnetic moments as they precess around B0 precessional (larmor) frequency - correct answer the speed of precession resonance - correct answer a phenomenon that occurs when an oscillating object is exposed to a frequency having the same or similar oscillating frequency to the object radio frequency (RF) - correct answer low energy, low frequency electromagnetic radiation radio frequency (RF) - correct answer What is used to excite hydrogen nuclei in MRI? excitation - correct answer application of an RF pulse that causes resonance to occur flip angle - correct answer the angle of the NMV to B0 longitudinal plane - correct answer the axis parallel to B0 transverse plane - correct answer the plane at 90 degrees to B0