Ch3 - Basic Principles of MR Signal Generation

Question 1

magnetic momentum

Answer 1

the torque (rotational force) exerted on a magnet, moving electrical charge, or current-carrying coil when it is placed in magnetic field

Question 2

angular momentum

Answer 2

a quantity given by multiplying the mass of a spinning body by its angular velocity

Question 3

right-hand rule

Answer 3

method used to determine the direction of a magnetic moment generated by a moving charge or electrical current
- if the fingers of the right hand are curled around the direction of spin, the magnetic momentum will be in the direction indicated by the thumb

Question 4

NMR property

Answer 4

label for atomic nuclei that have both a magnetic moment and angular momentum, which together allow them to exhibit nuclear magnetic resonance effects

Question 5

spins

Answer 5

atomic nuclei that possess the NMR property

I.e: they have magnetic moment and angular momentum

Question 6

spin system

Answer 6

collection of atomic nuclei that possess the NMR property within a spacial location

Question 7

net magnetization (M)

Answer 7

the sum of the magnetic moments of all spins within a spin system

Question 8

flux

Answer 8

a measure of the strength of a magnetic field over an area of space

Question 9

B0 (B zero)

Answer 9

The strong magnetic field generated by an MRI scanner

Question 10

precession

Answer 10

the gyroscopic motion of a spinning object, in which the axis of the spin itself rotates around a central axis, like a spinning top

Question 11

Lamor frequency

Answer 11

the resonant frequency of a spin within a magnetic field of a given strenght
- defines the frequency of electromagnetic radiation needed during excitation to make spins change to a high energy state, as well as the frequency emitted by spins when they return to the low-energy state