Introducing Color into the Image Contrast Parameters

Introducing Color into the Image Contrast Parameters 

First of all, one can introduce relaxation phenomenologically by amending the equation describing the time-dependence of the magnetization vector [Eq. (1.2)] by a decaying term  

What needs to be known to discuss the feasibility of a particular imaging experiment is a good estimate for the relaxation times of the system under study, which then need to be compared with the times required for executing the sequence, frequently determined by hardware limitations. In a simple liquid, one usually has T = T2 and both are in the range of several seconds. This is 

One further point needs to be mentioned when probing the feasibility of a particular experiment. Apart from its dependence on temperature and concentration (for instance of ions, solutes, impurities, isotopes), relaxation times - in particular the longitudinal relaxation time Tj - depend on the field strength. This can be understood from the concept that energy exchange is most efficient if the timescale of molecular motion is equal to the Larmor frequency. Often, molecular motion takes place over a wide range of frequencies, so that the func- 

Callaghan 1994, Principles of Nuclear Magnetic Resonance Microscopy, Clarendon Press, Oxford, 490 pp. Standard reference textbook for imaging, some examples but with a focus on theory. 

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Introducing Color into the Image Contrast Parameters 39... 

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