Methods of selectively enhancing or suppressing the signal from a particular molecular substance by using its spin properties, typically through spin spin coupling, e.g. J-modulation.

A spectral line is a particular distinct frequency or narrow band of a frequency set. The resonance of this frequency occurs corresponding to a particular chemical shift. Theoretically, the frequency of a pure sine wave displays sharp spectral lines at the point of Larmor frequency. In reality, the spectral lines spread into a blurred peak, caused by field inhomogeneities and spin-spin effect.

The mapping of a CSI spectral matrix to an anatomical image. It shows the regional changes in metabolites as superimposed contours.

(SPIR) A specialized technique that selectively saturates fat protons prior to acquiring data as in standard sequences, so that they produce a negligible signal. The presaturation pulse is applied prior to each slice selection. This technique requires a very homogeneous magnetic field and very precise frequency calibration.

(SPAIR) The MRI fat suppression technique SPAIR is characterized by a low sensitivity to RF field inhomogeneities. The used adiabatic radio frequency pulses for spectral saturation ensure a high uniformity and lower specific absorption rate (SAR).
SPAIR is suitable for offset and difficult to suppress regions such as liver, pelvis, shoulder and hips.