Image-guided localized proton and phosphorus MR spectroscopy

The clinical applicability of in vivo proton (H-1) and phosphorus (P-31) MR spectroscopy for diagnosing brain tumors and monitoring the effectiveness of radiation therapy was evaluated in 63 patients with large brain tumors who underwent imaging with a regular whole-body MR system operating at 1.5 T. H-1 MR imaging preceded spectroscopy in order to define the volume of interest within the lesion. Compared with those of normal brain tissue, spectra from meningiomas demonstrated the most obvious differences. In primary intracranial tumors, less distinct changes were seen. Calculation of tissue pH from P-31 resulted in normal values or values shifted to the alkaline range, even if lactic acid was demonstrated in tumor tissue with H-1 MR spectroscopy. In conclusion, H-1 and P-31 MR spectroscopy reveal complementary metabolic information on tumorous tissue, which might improved the diagnostic specificity of MR imaging