INVIVO H-1, P-31-(H-1) AND C-13-(H-1) MAGNETIC-RESONANCE SPECTROSCOPY OF MALIGNANT HISTIOCYTOMA AND SKELETAL-MUSCLE TISSUE IN MAN

Human tumor and skeletal muscle tissue was studied by means of in vivo H-1, P-31, and C-13 MRS. The examinations were performed with a 1.5 T whole-body MR scanner equipped with a second RF system. Localized H-1 and broadband proton-decoupled P-31 and C-13 MR spectra were obtained in measurement times of 5, 10 and 33 min, respectively, from a malignant fibrous histiocytoma in a patient and from gastrocnemius muscle tissue in healthy volunteers. Proton decoupling enhanced the sensitivity (via the nuclear Overhauser effect) and the information available from in vivo P-31 and C-13 MR spectra significantly. The most information was obtained from H-1-decoupled P-31 spectra. Observation of more than one spin species allows peak assignments to be verified mutually. The spectral data of the histiocytoma differ largely from that of muscle tissue and show a tumor with elevated pH value, normal level of nucleoside 5'-triphosphates, and high level of compounds involved in phospholipid turnover. The multinuclear in vivo MRS experiment may allow the non-invasive observation of almost the complete pathway of phospholipid synthesis and degradation in intact human tissue.