(NMR) Nuclear Magnetic Resonance is a physical phenomenon of the magnetic property of nuclei, which have a positive nuclear spin quantum number.
Under the influence of an external static magnetic field this nuclei will precess about the direction of the magnetic field with an angular frequency (Larmor frequency). Through absorption and emission of RF energy (gradients, RF coils) at the resonance frequency (Larmor equation) and the processing of this raw data by the Fourier transformation - physical, chemical, electronic, and structural information about molecules can be obtained (NMR Magnetic Resonance Spectroscopy, Magnetic Resonance Imaging).

The sensitive point in an object (or a region) is the point from which information is being measured, as in sequential point imaging or in single voxel MR spectroscopy sequential point imaging used. To define a sensitive point, it must be selected in three dimensions. Different combinations of selective excitation, inversion, or saturation pulses can be used. Sometimes, combinations of two or more measurements are necessary to define the sensitive point (or volume).

See also Magnetic Resonance Spectroscopy.

Edward Purcell and Felix Bloch discovered the basic of spectroscopy in 1946 (see MRI History). Nuclear magnetic resonance spectroscopy (NMR Spectroscopy or MRS) is an analytical tool, based on nuclei that have a spin (nuclei with an odd number of neutrons and/or protons) like 1H, 13C, 17O, 19F, 31P etc.
Through nuclear magnetic principles as precession, chemical shift, spin spin coupling etc., the analysis of the content, purity, and molecular structure of a sample is possible. The spectrum produced by this process contains a number of peaks; the highs and the positions of these peaks allow the exact analysis. Unknown compounds can be matched against spectral libraries. Even very complex organic compounds as enzymes and proteins can be determined. For the wide uses of NMR spectroscopy (from mineralogy to medicine) there is a variety of different techniques available.
See Spectroscopic Imaging Techniques.

From GE Healthcare;
The GE Signa HDx MRI system is a whole body magnetic resonance scanner designed to support high resolution, high signal to noise ratio, and short scan times.
The 1.5T Signa HDx MR Systems is a modification of the currently marketed GE 1.5T machines, with the main difference being the change to the receive chain architecture that includes a thirty two independent receive channels, and allows for future expansion in 16 channel increments. The overall system has been improved with a simplified user interface and a single 23" liquid crystal display, improved multi channel surface coil connectivity, and an improved image reconstruction architecture known as the Volume Recon Engine (VRE).