Chapter 1 Flashcards
___: refers to 3 forces (motion, magnetism and charge) and states that if two of these are present, then the third is automatically induced.
Faraday’s Law of Electromagnetic Induction
What is Larmor?
governs precessional frequency
What is NMV?
balance between spin-up and spin-down nuclei
What is resonance?
when an object is exposed to an oscillating perturbation that has a frequency close to its own natural frequency of oscillation
How are atoms characterized? Choose all correct …
- atomic number: the sum of the protons
* mass number: sum of the protons and the neutrons
What are the three types of motion within the atom? Choose all correct …
- electrons spinning on their own axis
- electrons orbiting the nucleus
- nucleus itself spinning about its own axis
Concerning the Larmor equation, what is Wo?
precessional frequency
Concerning the Larmor equation, what is Bo?
magnetic field strength of the magnet
Concerning the Larmor equation, what is Iamda?
gyrometric ration
What are the two results of resonance? Choose all that apply.
- NMV moves out of alignment with Bo
* magnetic moments move into phase with each other
Concerning T1 vs T2, what is T1 Recovery?
Recovery of 63% longitudinal magnetization. Aka: spin lattice.
Concerning T1 vs. T2, what is T2 Decay?
Results of 63% loss of transverse magnetization. Aka: spin spin
What is TR?
determines amount of T1
What is TE?
determines amount of T2
What is in phase?
Magnetic moments in the same place on the precessional path around Bo at any time. Aka coherent.
What is out of phase?
Not in the same place on the precessional path. Aka incoherent.
Which of the following is the Larmor equation?
precessional freq = MF strength * gyromagnetic ratio
TRUE of FALSE: An MRI active nucleus has even mass numbers and thus no net spin.
False
What is the 1T gyrometric ratio of Hydrogen?
42.57 MHz
What is the 1.5T gyrometric ratio of Hydrogen?
63.86 MHz
What is the 3T gyrometric ratio of Hydrogen?
127.71 MHz
What is the 0.5T gyrometric ratio of Hydrogen?
21.28 MHz
What is T1 Recovery?
caused by nuclei giving up energy to surrounding environment or lattice
What is T2 Decay?
magnetic fields of neighboring nuclei interacting with each other
T or F: the static magnetic field is Bo
true
T or F: The signal/voltage is only induced if there is coherent magnetization in the transverse plan that is in-phase
true
T or F: The isotope of Hydrogen is protium
true
T or F: high-energy nuclei align their magnetic moments in the anti-parallel direction are spin-down nuclei
true
