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Longitudinal Relaxation Enhancement in 1 H NMR Spectroscopy of Tissue Metabolites via Spectrally Selective Excitation
Author(s) -
Shemesh Noam,
Dumez JeanNicolas,
Frydman Lucio
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201300955
Subject(s) - excitation , relaxation (psychology) , nuclear magnetic resonance , excited state , spectroscopy , chemistry , nuclear magnetic resonance spectroscopy , metabolite , resonance (particle physics) , analytical chemistry (journal) , atomic physics , physics , biochemistry , chromatography , quantum mechanics , psychology , social psychology
Nuclear magnetic resonance spectroscopy is governed by longitudinal (T 1 ) relaxation. For protein and nucleic acid experiments in solutions, it is well established that apparent T 1 values can be enhanced by selective excitation of targeted resonances. The present study explores such longitudinal relaxation enhancement (LRE) effects for molecules residing in biological tissues. The longitudinal relaxation recovery of tissue resonances positioned both down‐ and upfield of the water peak were measured by spectrally selective excitation/refocusing pulses, and compared with conventional water‐suppressed, broadband‐excited counterparts at 9.4 T. Marked LRE effects with up to threefold reductions in apparent T 1 values were observed as expected for resonances in the 6–9 ppm region; remarkably, statistically significant LRE effects were also found for several non‐exchanging metabolite resonances in the 1–4 ppm region, encompassing 30–50 % decreases in apparent T 1 values. These LRE effects suggest a novel means of increasing the sensitivity of tissue‐oriented experiments, and open new vistas to investigate the nature of interactions among metabolites, water and macromolecules at a molecular level.