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.
Bibliographical noteFunding Information:
NIH Grants BTRC which is P41 EB015894 , P30 NS057091 , R01 NS061866 , S10 RR023730 , S10 RR027290 . The author S.M. thanks the grant KL2 RR033182 from the National Insititute of Health (NIH) to the University of Minnesota Clinical and Translational Science Institute (CTSI) for support.
- Fictitious fields
- High rotating frames