[31P-MR spectroscopy of bone and soft tissue lesions]

We studied 24 patients with bone and soft tissue lesions using 31P-MR spectroscopy (MRS). On image selected in vivo spectroscopy (ISIS) localized spectra, spectroscopic parameters were calculated: PME/noise ratio, gamma NTP/noise ratio, PME/gamma NTP and total metabolite signals (TMS). PME/noise, PME/gamma NTP and TMS were higher in malignant lesions than in benign ones. We set the criterion for malignancy as follows: PME/noise > 2.0 and gamma NTP/noise > 2.0 and PME/gamma NTP > 1.0. The accuracy of this criterion was 0.91 for malignant lesions and 1.0 for benign lesions. In six malignant tumors, MR spectra were obtained before and after chemotherapy. They were compared with the degree of tissue degeneration evaluated on pathological specimens. TMS after chemotherapy were markedly reduced in 3 cases. TMS seemed to reflect the degeneration of tumors. It could be said that MRS is a useful tool in differentiating from benign tumor lesions malignant bone or soft tissue lesions and in monitoring the effect of chemotherapy.