Combined 1H-MR imaging and localized 31P-spectroscopy of intracranial tumors in 43 patients.

Combined imaging and volume-selective spectroscopy of normal human brain tissue and tumors located anywhere in the brain could be obtained routinely in a clinical setting. Image-guided localized phosphorus MR spectra of healthy brain tissue have been reproducible, but further examinations seem necessary to determine individual physiologic variations. Compared with healthy brain tissue, spectra from meningiomas demonstrated the most obvious differences: the phosphocreatine peak decreased below the level of adenosine triphosphate, and the phosphodiester signal was reduced, whereas the phosphomonoester peak increased in some cases. Malignant gliomas showed less distinct changes: in particular, the phosphodiester peak was reduced and, in several cases, seemed to split. Often the phosphocreatine signal was diminished. In tumors with cystic components a poor signal-to-noise ratio was found. Four nonmalignant astrocytomas could not be differentiated from normal brain tissue spectroscopically. It has to be proved by an increased number of cases and quantification whether the observed spectral patterns can be correlated to histology. In three patients, follow-up studies during and after radiotherapy were performed. Metabolic changes were observed in one patient in a time frame in which imaging methods did not detect any change. Phosphorous spectroscopy has the potential to emerge as a useful tool in this field.