Phosphorus MR spectroscopy in the treatment of human extremity sarcomas

The application of P-31 MR spectroscopy in the characterization and treatme nt of malignant human extremity tumors is reviewed and placed in the perspe ctive of results obtained in murine sarcomas. Despite the now widespread ac quisition of gradient localized spectral maps, the low spatial resolution t hat can be achieved at 1.5 or 2 T with P-31 MRS, greatly limits its use in the study of tumor heterogeneity. The potential of P-31 MRS is in the evalu ation and monitoring of large inoperable extremity tumors. There are early spectral changes in human extremity sarcomas monitored after therapy, and r ecent studies have shown that the P-31 MR spectra measured before treatment , and the changes in phosphate metabolites measured shortly thereafter, cor relate with the clinical response after 2 or 3 months. Larger clinical stud ies are needed to confirm whether correlations of, for instance, pretreatme nt tumor pH with necrosis at resection and P-i decrease with tumor regressi on, can be used as a predictive test for clinical response. (C) 1998 John W iley & Sons, Ltd.