Effects of T2 Relaxation and Diffusion on Longitudinal Magnetization State and Signal Build for HOMOGENIZED Cross Peaks

An analytical expression has been developed to describe the effects of T2 relaxation and diffusing spatially modulated longitudinal spins during the signal build period of an HOMOGENIZED cross peak. Diffusion of the longitudinal spins results in a lengthening of the effective dipolar demagnetization time, delaying the re-phasing of coupled anti-phase states in the quantum picture. In the classical picture the unwinding rate of spatially twisted magnetization is no longer constant, but decays exponentially with time. The expression is experimentally verified for the HOMOGENIZED spectrum of 100mM TSP in H2O at 4.7T. More Keywords: magnetic resonance spectroscopy, MRS, intermolecular multiple quantum coherence, iMQC, intermolecular zero quantum coherence, iZQC, distant dipolar field, DD