MRI - PRELIM L3 Flashcards
The intrinsic angular momentum of
an atomic nucleus, much like how electrons have spin. The
concept comes from quantum mechanics and describes a
property of nucleons (protons and neutrons) inside the nucleus
Nuclear Spin
Determines the energy levels of the nucleus in an external magnetic field, which can be detected and used to gather information about the environment around
the nucleus.
Nuclear Spin
TRUE OR FALSE
The value of the nuclear spin depends on the number
and types of nucleons in the nucleus
TRUE
Nuclei with an even number of nucleons usually have ________ nuclear spin
Zero
Nuclei with an odd number of nucleons often have ________ nuclear spin
Non-zero
A fundamental law of physics states that a spinning, charged mass induces a magnetic field about itself.
Magnetic Moment
The nucleus is a spinning, charged particle and
therefore has an associated magnetic field. This
field is given the special name of
Nuclear Magnetic Moment
Ratio of the magnetic moment to the angular momentum of a particle; this is a constant for a given nucleus
Gyromagnetic Ratio
Gyromagnetic Ratio is measured in _______
MHz / T
The frequency of precession for nuclei with non-zero spin is _______ to the gyromagnetic ratio
Directly Proportional
Mew (μ) corresponds to the _________
Magnetic Moment of a Particle
The angular momentum or spin of the particle is represented by ____
J
The Gyromagnetic Ratio for Hydrogen-1 is ______
42.6 MHz/T
The Gyromagnetic Ratio for Fluorine is ______
40.1 MHz/T
The Gyromagnetic Ratio for Phosphorus is ______
17.2 MHz/T
The Gyromagnetic Ratio for Sodium is ______
11.3 MHz/T
The Gyromagnetic Ratio for Carbon is ______
10.7 MHz/T
The Gyromagnetic Ratio for Hydrogen-2 is ______
6.5 MHz/T
The Gyromagnetic Ratio for Oxygen is ______
5.8 MHz/T
The Gyromagnetic Ratio for Potassium is ______
2.0 MHz/T
A single, isolated nucleus is never observed, just collections of
similar nuclei as an ______
Aggregate
The Aggregate of Spins is sometimes called as _________ to emphasize the bulk of the signal-producing nuclear spins.
Ensemble of Spins
Net Magnetization formula is written as:
M = Σμ
The process by which atomic nuclei are exposed to a strong magnetic field and then to a pulse of radiofrequency energy.
Resonance
The specific frequency at which this energy is absorbed by the nuclei is called the _________
Resonance Frequency
The electromagnetic radiation produced by the oscillator is called a ________
Radiofrequency Emission
An electromagnetic emission such as a radiofrequency (RF) is composed of an oscillating electric field positioned _______ to an oscillating magnetic field.
90 Degrees
The formula for Larmor Frequency is written as _______
f = γB0
Used by mathematicians to diagram phenomena in space(X, Y, and Z) drawn perpendicular to one another
to describe a coordinate system.
Cartesian Coordinate System
A quantity that has direction
Vector
Which tissue has the highest Relative Spin Density and how many ?
Cerebrospinal Fluid = 100
As a hydrogen nuclei relax, they emit radiofrequency signals at the same
frequency they absorbed when they were flipped.
Signal Emission
Represents a loss of net XY magnetization and the loss of phase coherence in a plane perpendicular to or transverse to M0
T2 Relaxation Time
It is the amount of time
for the transverse magnetization to reach equilibrium
T1 Relaxation Time
It is reasonable to expect that one of the parameters that affects the amplitude of the magnetic resonance (MR signal) might be the _________ within the volume of the sample
Number of Hydrogen Nuclei
