Fast spin-echo technique

Tl Weighted Spin Echo Sequences 62 T2 Weighted Spin Echo Sequences 64 Proton Density Imaging 64 Fast Spin Echo Techniques 64... 

Sodickson A, Mortele KJ, Barish MA et al (2006) Three-dimensional fast-recovery fast spin-echo MRCP comparison with two-dimensional single-shot fast spin-echo techniques. Radiology 238 549-559... 

The reduction of obtainable light-pulse durations down to subpicosecond pulses (halfwidth about 10 sec) allows fast transient phenomena which were not accessible before to be studied in the interaction of light with matter. One example is the extension of spin echoe-techniques, well known in nuclear-magnetic-resonance spectroscopy, to the photon echoes in the optical region. 

Chang and Woessner, using the spin-echo technique, made and TU measurements on eletal muscle (115). While the curve Is cfbse to a single exponential decay, the T2 curve can be fitted with a double exponential function. The fast and slow (f,s) components have T values of 16 and 1.6 ms, respectively, for fresh muscle. The value for the same sample Is 18 ms. Hence, T. - Tg- < Tgg and Tgg = T. The reader will recall (Section 2 that T g depends upon the spectral density at twice the Larmor frequency, T depends on J((o whereas Tgf depends upon spectral densities at zero emd at Larmor frequency and Tgg depends upon the sum J(o) + J(2a>). Thus, the experimental results obtained by Chang emd Woessner Imply that J(0)>>J(o) ) = J(2oj ). This last equality. In turn. Indicates... 

T2-weighted gradient-echo sequences with the steady-state free precession (SSFP) technique were initially usedby Wallner et al. (1991), Morimoto et al. (1992),HALL-CRAGGsetal. (1993), and IsmzAKiet al. (1993). Subsequently, other investigators have utilized two-dimensional (2D) and three-dimensional (3D) heavily T2-weighted fast spin-echo sequences... 

While morphologic MRI with regard to mass assessment, detailed soft tissue differentiation, and cardiac morphology, is mainly carried out on T1-weighted or T2-weighted fast spin-echo (FSE) techniques, the majority of todays applications is covered with the use of gradient-recalled-echo (CRE) techniques. 

Turbo spin-echo/fast spin-echo (TSE/FSE) is the well accepted sequence for obtaining breath-hold T2-weighted images (Kanematsu et al. 1999). The TSE/FSE technique shows a tissue contrast similar to that of conventional T2-weighted SE images, but... 

Localized NMR spectroscopy, which is often called as MRS in comparison with MRI, is not so familiar technique in food science, because a specific pulse sequence such as ISIS and a facility which can precisely follow the pulse sequence without any contamination from other position is needed for localization of position. The localized NMR is usually used together with NMR imaging. The study of solid/liquid ratios, fat structure and polymorphism and the kinetics of fat crystallization was reviewed [24], The potential of applications in food process development and control was offered. The localized spectra of sausages in areas of 0.3 mm X 0.05 mm (thickness of sample =1.5 mm) were obtained by the spin echo 2DFT method [113], in which the difference in the tissue structure was discussed with relation to the process and original materials. McCarthy et al. determined mobility of water in foams by using a localized spectroscopy [114]. T2 relaxation time varies in the foam as function of diameter and its variation was analyzed by the classic 2-state fast exchange model. 

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