Magnetic Resonance Imaging (MRI) and Magnetic Resonance Spectroscopy (MRS)
Magnetic resonance imaging (MRI) has a wide range of applications in medical diagnosis and preclinical research. MRI was invented about 40 years ago, and there are currently estimated to be over 25,000 scanners in the world. In general, contrast agents are not necessary for MRI and the soft tissue contrast of MRI is better than other imaging techniques. The important point is that MRI intensity depends on not only the concentration but also physico-chemical properties of molecules in tissues. In the first part of this chapter, several kinds of MRI techniques are described. Magnetic resonance spectroscopy (MRS) is an application of magnetic resonance. The second part of this chapter is concerned with MRS. This technique provides information in metabolism non-invasively, and obtains spectra from a region of interest two- and three-dimensionally. Some physiological parameters, such as pH and temperature, can be estimated by the spectra. Applications of MRI and MRS are very broad, since many factors affect MRI signals. Functional MRI (fMRI) is an important application used widely in the neurosciences, human sciences, and economics, as well as in medical sciences. The major restriction of MRI is its long scan time. An accelerated technique is described in the last part of the chapter.
KeywordsMagnetic resonance imaging Magnetic resonance spectroscopy fMRI Cell tracking Compressed sensing
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