Clinical applicability of human in vivo localized phosphorus-31 magnetic resonance spectroscopy of bone and soft tissue tumors
Background: Magnetic resonance imaging (MRI) is of restricted value for the in vivo characterization of tumor types. The applicability of phosphorus-31 (31P) magnetic resonance spectroscopy (MRS) in the diagnosis of bone and soft tissue tumors is unknown. Methods: A total of 191 consecutive patients (85 females and 106 males; mean age 41 years, range 1–80) with a well-defined bone or soft tissue tumor on MRI were analyzed for additional31P spectroscopy. Histology and/or cytology was obtained from all tumors. Because of low sensitivity of the31P nucleus and the contamination of surrounding tissue, only large, superficially located tumors accessible to the surface coil could be accepted for MRS. Results: Twenty-one patients (11%) could be included in the study. From this remaining group only 12 studies (57%) produced spectra with well resolved phosphorus peaks and an acceptable signal-to-noise ratio. However, these spectra did not allow differentiation between the benign and malignant nature of the lesions. The other 9 studies showed spectra with poor signal intensities and/or poorly defined peaks, making tumor differentiation impossible. Conclusion: Only 6% of the bone and soft tissue tumors produced well defined spectra, which implies that localized31P MRS cannot be considered as a routine technique in the diagnostic and treatment evaluation of bone and soft tissue tumors.