Magnetism in MRI

This set of flashcards covers key vocabulary and concepts related to magnetism in MRI, including definitions of important terms such as precessional frequency and types of magnetic materials.

Precessional Frequency

The resonant frequency of a nucleus in a magnetic field, defined as the product of the magnetic field and the gyromagnetic ratio.

Larmor Equation

The equation used to calculate the precessional frequency of a proton in a magnetic field, typically expressed as 42.57 MHz per Tesla.

T1 Relaxation

The process in which nuclei give up their energy to surrounding tissue, allowing for recovery of longitudinal magnetization.

T2 Relaxation

The decay of transverse magnetization, representing the time it takes for spins to de-phase.

Ferromagnetic Materials

Substances, like iron, that can generate a strong magnetic field and are attracted to magnetic fields.

Paramagnetic Materials

Materials that have a weak magnetic field; gadolinium is a common example used in MRI contrast.

Superconducting Magnet

A type of magnet commonly used in MRI systems due to high field strength and imaging capabilities.

Magnetic Susceptibility

The degree to which a material becomes magnetized in an external magnetic field.

Longitudinal Magnetization

The net excess of hydrogen protons aligned with the static magnetic field.

Free Induction Decay (FID)

The signal produced from the relaxation of magnetization after an RF pulse is applied.

Spin-Lattice Relaxation

Also known as T1 recovery, it is the return of longitudinal magnetization to equilibrium.

Spin-Spin Relaxation

The return of transverse magnetization to equilibrium, characterized by the time T2.

Magnetic Field Inhomogeneity

Variations in the magnetic field strength, expressed in parts per million (ppm).