Noninvasive characterisation of intracranial tumours by in vivo proton magnetic resonance spectroscopy

We studied the possibility of tissue characterisation of intracranial tumours by localised proton magnetic resonance spectroscopy (1H-MRS). Twenty-six newly diagnosed tumours were examined by in vivo 1H-MRS. The N-acetyl aspartate/choline (NAA/Cho ratio of grade 2 astrocytomas was relatively higher than that of those of grade 4. The choline/creatine (Cho/Cr) ratio of meningiomas was considerably higher than that of gliomas of all grades. We found only 2 cases of ependymoma, and the Cho/Cr ratio in both was lower than that in other gliomas. We considered that 1 H-MRS can be used to differentiate grade 2 from grade 4 in most cases of astrocytoma by the NAA/Cho ratio, though a few cases will overlap. Meningioma can easily be separated from glioma, and the results of our study suggest that ependymoma has a characteristic pattern.