NMR spectral lines may consist of groups of lines called multiplets. This multiplet structure is caused by interactions between nuclei that split the NMR energy levels and result in the observation of multiple allowed transitions separated by an amount of energy related to J, the spin spin coupling constant. These interactions are called spin spin coupling.

One of a number of techniques designed to minimize the contribution of a particular component of the object to the detected signal. For example, commonly used to suppress the strong signal from water in order to detect spectral line from other components.

See also Fat Suppression and Water Suppression.

A surface coil placed over a region of interest will have an effective selectivity for a volume approximately subtended by the coil circumference and one radius deep from the coil center. Such a coil can be used for simple localization of sites for measurement of chemical shift spectra, especially of phosphorus, and blood flow studies. Some additional spatial selectivity can be achieved with magnetic field gradients.

(WFS) The water fat shift defines the frequency bandwidth resulting in pixel shift due to the water/fat spectral separation. WFS decreases or increases to a specified number of pixels in mm. The amount of WFS is proportional to the main magnetic field.

See Bandwidth.