MRS allows non-invasive in-vivo exploration of tissue metabolism.
However,about half of the proton spectrum (downfield of water) has been nearly
ignored over the decades of MRS application due to water suppression.We show
that ISIS-based Relaxation Enhanced MRS (iRE-MRS) which uses frequency
selective excitation and ISIS localization offers short echo times and enhances
exchange-broadened resonances.We measure the T1s and calculate signal decay
due to T2 relaxation and find that downfield peaks show a signal decrease of
more than 50% when increasing TE from 5 to only 16 ms.Calculated T1 values are
in the range of 1.55-1.75 s.