METABOLIC CHARACTERIZATION OF HUMAN SOFT-TISSUE SARCOMAS IN-VIVO AND IN-VITRO USING PROTON-DECOUPLED PHOSPHORUS MAGNETIC-RESONANCE SPECTROSCOPY

We applied H-1-decoupling and nuclear Overhauser enhancement to obtain web-resolved P-31 magnetic resonance spectra accurately localized to 20 soft tissue sarcomas in vivo, using three-dimensional chemical shif t imaging. Fifteen spectra had large phosphomonoester signals (21% of total phosphorus) that contained high amounts of phosphoethanolamine ( compared to those of phosphocholine) but no signals from glycerophosph oethanolamine, and glycerophosphocholine was detected in only four cas es. Prominent nucleoside triphosphates (52% of phosphorus) and low ino rganic phosphate (10% of phosphorus) indicated that a large fraction o f these 15 sarcomas contained viable cells, and this impression was co nfirmed histologically in 13 of the sarcomas. High-resolution in vitro P-31 spectra of extracts of surgical specimens of four of the sarcoma s studied in vive and six additional sarcomas confirmed the in vive as signments of metabolites and revealed considerable inter- and intratum oral variations of metabolite concentrations associated with histologi cal variations in the relative amounts of cells and of matrix material s or spontaneous necrosis. Seven sarcomas, all high grade with pleomor phic or round cells rather than spindle cells, contained an unidentifi ed phosphodiester signal in vivo; its absence in the extract spectra i ndicates that it may be from an abnormally mobile membrane component. We have documented a means to obtain new information about in vive met abolism in human sarcomas and to provide a basis on which to examine t he uses of P-31 magnetic resonance spectroscopy in the clinical manage ment of sarcomas.