منابع مشابه
Long-time behavior of nuclear spin decays in various lattices
The transverse NMR decays of 129Xe in polycrystalline xenon were recently shown to have a universal property: in the long-time regime these decays all converge to the same sinusoidally modulated exponential function irrespective of the initial transverse spin configuration prepared by a sequence of one or more radio frequency pulses. The present work constitutes a more comprehensive survey of t...
متن کاملcomparison of maximum signal intensity of magnevist contrast agent in modified t1 weighted spin echo, t1 weighted fast spin echo and t1 weighted gradient echo sequences
background: nowadays mri examinations have been widely used in clinical applications for many diagnoses. the use of contrast agent in mri improves lesion detection and characterization and causes more accurate diagnosis. objectives: the aim of this study was comparing to optimal dose of magnevist contrast agent in modified t1w se (spin echo), t1w fse (fast spin echo) and t1w gre (gradient ech...
متن کاملAssessment of the Characteristics of MRI Coils in Terms of RF Non-Homogeneity Using Routine Spin Echo Sequences
Introduction: One of the major causes of image non-uniformity in MRI is due to the existence of non-homogeneity in RF receive and transmit. This can be the most effective source of error in quantitative studies in MRI imaging. Part of this non-homogeneity demonstrates the characteristics of RF coil and part of it is due to the interaction of RF field with the material being imaged...
متن کاملTime Dependent Self-diffusion by Nmr Spin-echo
The relation between the NMR spin-echo attenuation in the magnetic field gradient and the velocity autocorrelations of molecular random migration has been derived by using the commulant expansion theorem for averaging stochastic processes. It may explain certain cases of time dependent diffusion observed in many systems. In the limit of long correlation times it is identical to Torrey’s well-kn...
متن کاملFast Spin Echo Imaging
In conventional spin echo (SE) imaging, the longitudinal magnetization (that is generated by the presence of the main magnetic field, B0) is tipped into the transverse plane using a radiofrequency (RF) pulse that tips the magnetization 90 degrees. Once in the transverse plane, the magnetization rotates, or precesses, around the axis of the main magnetic field. As the transverse magnetization pr...
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ژورنال
عنوان ژورنال: Physical Review Letters
سال: 2005
ISSN: 0031-9007,1079-7114
DOI: 10.1103/physrevlett.94.247601