Magnetic chemical shift imaging

Figure Bl.14.7. Chemical shift imaging sequence [23], Bothx- andj -dimensions are phase encoded. Since line-broadening due to acquiring the echo in the presence of a magnetic field gradient is avoided, chemical shift infonnation is retained in tire echo.

H. Rumpel, J. M. Pope 1993, (Chemical shift imaging in nudear magnetic resonance a comparison of methods), Cone. Magn. Reson. 5, 43. 

Fig. 7 A chemical shift imaging pulse sequence. The MR signal is spatially encoded prior to acquiring the spectral signal in the absence of any applied magnetic field gradients. The shaded gradient pulses applied along z either side of the n refocusing pulse are homospoil gradients.

T. Sassa, T. Suhara, H. Ikehira, T. Obata, F. Girard, S. Tanada, Y. Okubo, 19F-magnetic resonance spectroscopy and chemical shift imaging for schizophrenic patients using haloperidol decanoate. Psychiatry Clin. Neurosci. 56 (2002) 637-642. 

T. Fujimoto, T. Nakano, T. Takano, Y. Hokazono, T. Asakura and T. Tsuji, Study of chronic schizophrenics using P magnetic resonance chemical shift imaging. Acta Psychiatr. Scand., 1992, 86,4554 62. 

Bottomley PA (1987) Spatial localization in NMR spectroscopy in vivo. Ann NY Acad Sci 508 333-348 Bottomley PA, Edelstein WA, Foster TH, Adams WA (1985) In vivo solvent-suppressed localized hydrogen nuclear magnetic resonance spectroscopy a window to metabolism Proc Natl Acad Sci USA 82 2148-2152 Brown TR, Kincaid BM, Ugurbil K (1982) NMR chemical shift imaging in three dimensions. Proc Natl Acad Sci USA 79 3523-3526... 

In CT, contrast occurs solely because of the attenuation of the X-ray beam by its interaction with tissue. Contrast in MRI depends on how the image is acquired. Proton density images reflect the different amounts of water content in different tissues. Chemical shift imaging can distinguish water from fat, based on the different chemical shifts of these protons. Contrast also can be altered in other ways by the exploitation of differences in water diffusion in tissue, by chemical exchange, and by magnetization transfer effects, to name a few. The majority of scans used clinically derive contrast from differences in the relaxation times Ti, T2, and T2. ... 

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