MR001 Final Study Set Exam
active shielding - Answer using an opposing magnetic field to push against the b0 field
atomic number - Answer the number of protons in the nucleus
superconductive magnets - Answer High field strength, supercooled scanner (cryogen
circulates helium)
t2 decay (tissues) - Answer nuclei lose phase due to bumping into each other (spin-spin
interaction) in the TRANSVERSE place
t2 decay time - Answer time it takes for 63% of transverse magnetization to decay
diamagnetic substances - Answer no unpaired electrons, no magnetism
ferromagnetic substances - Answer several unpaired electrons, strong magnetism
paramagnetic substances - Answer one or more unpaired electrons, magnetized when
exposed to a magnetic field, slightly magnetized
super-paramagnetic - Answer magnetized when exposed to a magnetic field, heavily
magnetized
gradients - Answer loops of copper wire (coils) in the bore wall that generate TVMF
(time-varying magnetic field)
physical gradients - Answer x,y,z
logical gradients - Answer SS (slice selection), PE (phase encoding), FE (frequency
encoding)
function of gradients - Answer spatially locate or encode signal in 3 dimensions,
dephase (spoiling) /rephase (rewinding) nuclei, produce an echo, alter B0 linearly,
cause magentophosphenes and peripheral nerve stim
Motions of an atom - Answer 3 spins: nucleus spins, electron spins, and electron orbits
magnetic moments - Answer small magnetic fields, generated by motions of an atom
MR active nuclei - Answer nuclei that have a charge in motion, generating a magnetic
moment
isotopes - Answer Atoms with the same number of protons but different numbers of
neutrons
law of electromagnetism - Answer (charge, motion, magnetism) if 2 forces are present,
the 3rd will be induced
TR value for PDW images in Spin Echo sequence - Answer long TR, short TE
active shielding - Answer using an opposing magnetic field to push against the b0 field
atomic number - Answer the number of protons in the nucleus
superconductive magnets - Answer High field strength, supercooled scanner (cryogen
circulates helium)
t2 decay (tissues) - Answer nuclei lose phase due to bumping into each other (spin-spin
interaction) in the TRANSVERSE place
t2 decay time - Answer time it takes for 63% of transverse magnetization to decay
diamagnetic substances - Answer no unpaired electrons, no magnetism
ferromagnetic substances - Answer several unpaired electrons, strong magnetism
paramagnetic substances - Answer one or more unpaired electrons, magnetized when
exposed to a magnetic field, slightly magnetized
super-paramagnetic - Answer magnetized when exposed to a magnetic field, heavily
magnetized
gradients - Answer loops of copper wire (coils) in the bore wall that generate TVMF
(time-varying magnetic field)
physical gradients - Answer x,y,z
logical gradients - Answer SS (slice selection), PE (phase encoding), FE (frequency
encoding)
function of gradients - Answer spatially locate or encode signal in 3 dimensions,
dephase (spoiling) /rephase (rewinding) nuclei, produce an echo, alter B0 linearly,
cause magentophosphenes and peripheral nerve stim
Motions of an atom - Answer 3 spins: nucleus spins, electron spins, and electron orbits
magnetic moments - Answer small magnetic fields, generated by motions of an atom
MR active nuclei - Answer nuclei that have a charge in motion, generating a magnetic
moment
isotopes - Answer Atoms with the same number of protons but different numbers of
neutrons
law of electromagnetism - Answer (charge, motion, magnetism) if 2 forces are present,
the 3rd will be induced
TR value for PDW images in Spin Echo sequence - Answer long TR, short TE
