The effect of the applied RF field in an NMR experiment on the magnitude of the Spectral Density ... more The effect of the applied RF field in an NMR experiment on the magnitude of the Spectral Density for a Dipolar Relaxation Mechanism is demonstrated theoretically. The effect was shown with Sin Cos Pulse as a concrete example. The order of magnitude of the magnetic moment where these effects will be significant for typical Rf amplitude values was derived. The effect may be of utility in providing an alternate method of control for MRI Tissue Contrast applications with further development.
In the present study we derive expressions for relaxation rate functions due to dipolar interacti... more In the present study we derive expressions for relaxation rate functions due to dipolar interactions between identical spins in the rotating frames of rank greater than or equal to 3. The rotating frames are produced due to fictitious magnetic field as generated by amplitude and frequency modulated radiofrequency (RF) pulses operating in non-adiabatic regime. This solution provides a means for description of the relaxations during method entitled Relaxation Along a Fictitious Field (RAFF) in the rotating frame of rank n (RAFFn), in which a fictitious field is created in a coordinate frame undergoing multi-fold rotation about n axes (i.e., rank n). We validate the proposed model by comparison with the accepted trigonometric relations for relaxation rates between tilted frames. The agreement between the proposed model for RAFF3 and the trigonometric model is excellent.
In the present study we derive a solution for two site fast exchange-induced relaxation in the pr... more In the present study we derive a solution for two site fast exchange-induced relaxation in the presence of a fictitious magnetic field as generated by amplitude and frequency modulated RF pulses. This solution provides a means to analyze data obtained from relaxation experiments with the method called RAFFn (Relaxation Along a Fictitious Field of rank n), in which a fictitious field is created in a coordinate frame undergoing multi-fold rotation about n axes (rank n). The RAFF2 technique is relevant to MRI relaxation methods that provide good contrast enhancement for tumor detection. The relaxation equations for n = 2 are derived for the fast exchange regime using density matrix formalism. The method of derivation can be further extended to obtain solutions for n > 2. Published by Elsevier Inc.
The effect of the applied RF field in an NMR experiment on the magnitude of the Spectral Density ... more The effect of the applied RF field in an NMR experiment on the magnitude of the Spectral Density for a Dipolar Relaxation Mechanism is demonstrated theoretically. The effect was shown with Sin Cos Pulse as a concrete example. The order of magnitude of the magnetic moment where these effects will be significant for typical Rf amplitude values was derived. The effect may be of utility in providing an alternate method of control for MRI Tissue Contrast applications with further development.
In the present study we derive expressions for relaxation rate functions due to dipolar interacti... more In the present study we derive expressions for relaxation rate functions due to dipolar interactions between identical spins in the rotating frames of rank greater than or equal to 3. The rotating frames are produced due to fictitious magnetic field as generated by amplitude and frequency modulated radiofrequency (RF) pulses operating in non-adiabatic regime. This solution provides a means for description of the relaxations during method entitled Relaxation Along a Fictitious Field (RAFF) in the rotating frame of rank n (RAFFn), in which a fictitious field is created in a coordinate frame undergoing multi-fold rotation about n axes (i.e., rank n). We validate the proposed model by comparison with the accepted trigonometric relations for relaxation rates between tilted frames. The agreement between the proposed model for RAFF3 and the trigonometric model is excellent.
In the present study we derive a solution for two site fast exchange-induced relaxation in the pr... more In the present study we derive a solution for two site fast exchange-induced relaxation in the presence of a fictitious magnetic field as generated by amplitude and frequency modulated RF pulses. This solution provides a means to analyze data obtained from relaxation experiments with the method called RAFFn (Relaxation Along a Fictitious Field of rank n), in which a fictitious field is created in a coordinate frame undergoing multi-fold rotation about n axes (rank n). The RAFF2 technique is relevant to MRI relaxation methods that provide good contrast enhancement for tumor detection. The relaxation equations for n = 2 are derived for the fast exchange regime using density matrix formalism. The method of derivation can be further extended to obtain solutions for n > 2. Published by Elsevier Inc.
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Papers by Dennis Sorce