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LARMOR EQUATION
An equation that states that the frequency of precession of the nuclear magnetic moment is directly proportional to the product of the magnetic field strength (Bo) and the gyromagnetic ratio (g). This is stated mathematically as å = g Bo.
LARMOR FREQUENCY
The frequency at which magnetic resonance in a nucleus can be excited and detected. The frequency varies directly with magnetic field strength, and is normally in the radio frequency (RF) range.
LATTICE
In MRI, the magnetic and thermal environment through which nuclei exchange energy in longitudinal (T1) relaxation.
LONGITUDINAL MAGNETIZATION
The component (MZ) of the net magnetization vector in the direction of the static magnetic field. After RF excitation, this vector returns to its equilibrium value at a rate characterized by the time constant T1.
LONGITUDINAL RELAXATION
Return of longitudinal magnetization to its equilibrium value after excitation due to the exchange of energy between the nuclear spins and the lattice.
LONGITUDINAL RELAXATION TIME
The time constant, T1, which determines the rate at which excited protons return to equilibrium within the lattice. A measure of the time taken for spinning protons to realign with the external magnetic field. The magnetization will grow after excitation from zero to a value of about 63% of its final value in a time of T1.
