(NOE) A change in the steady state magnetization of a particular nucleus due to irradiation of a neighboring nucleus with, which it is coupled by means of a spin spin coupling interaction. This interaction must be the primary relaxation mechanism of these nuclei. Such an effect can occur during decoupling and must be taken into account for accurate intensity determinations during such procedures.

A state occurring when the Larmor frequency of a spin isochromat is different from that of the exciting RF field.

See also Magnetization Transfer Contrast.

A state occurring when the Larmor frequency of a spin isochromat is the same as that of the exciting RF field.

See also Magnetization Transfer Contrast.

(PARACEST) The alteration of the proton density or total water signal changes contrast and can be detected by the MRI scanner. Paramagnetic chemical exchange saturation transfer contrast agents are based upon the magnetization transfer mechanism.
Lanthanide ion complexes formed with tetra-amide based ligands display unusually slow water exchange kinetics and this feature may be used to alter image contrast by applying a selective presaturation pulse in an imaging sequence. This results in chemical exchange saturation transfer (CEST) from the lanthanide-bound water to bulk water thereby altering image contrast.
Chemical Exchange Saturation Transfer (CEST) agents are a class of contrast agents that could potentially revolutionize the MRI field because of their improved sensitivity and can have a great impact on functional magnetic resonance imaging.

Time duration of a pulse. For an RF pulse near the Larmor frequency, the longer the pulse length, the greater the angle of rotation of the macroscopic magnetization vector will be (greater than 180° can bring it back toward its original orientation). For an RF pulse of a given shape as a function of time, the longer the pulse length, the narrower the equivalent range of frequencies in the pulse will be.