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Sensitivity enhancement in whole‐body natural abundance 13 C spectroscopy using 13 C/ 1 H double‐resonance techniques at 4 tesla
Author(s) -
Bomsdorf H.,
Röschmann P.,
Wieland J.
Publication year - 1991
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910220103
Subject(s) - nuclear magnetic resonance , sensitivity (control systems) , spectroscopy , resonance (particle physics) , magnetic resonance imaging , physics , materials science , medicine , atomic physics , radiology , engineering , quantum mechanics , electronic engineering
In vivo 13 C spectroscopy experiments were performed using a whole‐body MR system at a static field of 4 T. The main goal of the investigations was to evaluate the sensitivity increase achievable by means of 13 C/ 1 H double‐resonance techniques at 4 T. Spectra from subcutaneous fat as well as muscle glycogen from the lower leg were acquired using frequency selective proton decoupling and the polarization transfer method SINEPT. With respect to measurements on subcutaneous fat, polarization transfer turned out to be more efficient than selective decoupling. About a fourfold enhancement in spectral peak intensity for the CC line doublet of the unsaturated fatty acid chain was obtained. Combining polarization transfer with decoupling yielded a factor of 6 in signal amplitude. In contrast to that, the signal enhancement observed in measurements on the glycogen C‐1 resonance was only around twofold. The lower efficiency is explained by fast T 2 relaxation of the proton transition. A T 2 value of about 3 ms was derived from the experimental data. Acquisition times as low as 3 min were realized for normal level glycogen in human calf muscle, enabling a time resolution adequate for dynamic studies on muscle glycogen depletion. Aspects of RF power absorption in tissue and the generally higher efficiency make polarization transfer methods preferable to selective decoupling in whole‐body 13 C spectroscopy at 4 T. © 1991 Academic Press, Inc.