MRS characterization of central neurocytomas using glycine.

This study reports in vivo MRS findings in 11 patients with histologically diagnosed central neurocytomas, which are rare intraventricular tumors of neuronal origin. Single-voxel (1)H MRS was carried out prior to surgery using a point-resolved spectroscopy sequence with TR=6 s, TE=135 ms and 128 scans. In vitro high-resolution (1)H spectroscopy was also carried out on two surgically excised samples. The striking features of the spectra from the central neurocytomas were the presence of high glycine, decreased N-acetylaspartate, increased choline and alanine. Retrospective, blind analysis of the spectra by two independent observers correctly identified all but one central neurocytoma based on the presence of glycine. The presence of glycine and prominent choline in the (1)H MR spectrum is a characteristic feature of the central neurocytomas, and could be used to characterize and differentiate them from other brain tumors.