Sequence of RF (and gradient) pulses designed to produce saturation, typically in a selected region or set of regions, most often by the use of selective excitation followed by a spoiler pulse. Similar to some spectral suppression techniques. Can be used to reduce signal from flowing blood by saturating regions upstream from region being imaged.

The range of diagnostics and imaging systems of Siemens Medical Systems covers ultrasound, nuclear medicine, angiography, magnetic resonance, computer tomography and patient monitoring. Siemens is one of the three leading MRI manufacturers, which together account for approximately 80 percent of the MRI machines installed worldwide. Siemens currently offers the Allegra 3T MRI, which is for head scanning only, but the company will also be launching the Trio MRI, a 3T whole body scanner.
Siemens has formed partnerships with more than ten research institutions and private practitioners to define a comprehensive MRI examination and compare MR to currently established cardiovascular modalities, thereby defining optimal diagnosis and treatment.

MRI Scanners:

0.2T to 1.0T:
1.5T:
3.0T to 7.0T:
Hybrid Scanners:
Mobile Solutions:

Process by which regions of tissue are selectively sampled to produce spectra from defined volumes in space. These methods may be employed to sample a single region in space (single voxel method) or multiple regions simultaneously (multivoxel methods). The spatial selectivity can be achieved by a variety of methods including surface coils, surface coils in conjunction with RF gradient methods, or RF pulses in combination with switched magnetic field gradients, for example, volume-selective excitation. An indirect method of achieving spatial selectivity is the destruction of coherence of the magnetization in regions that lie outside the region of interest. A variety of spatial encoding schemes have been employed for multivoxel localization. See Chemical shift imaging.

For the wide uses of NMR spectroscopy (from mineralogy to medicine) there is a variety of different spectroscopic imaging techniques available.
A short listing of the most frequent variations:

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.