Possible role of single-voxel ¹H-MRS in differential diagnosis of suprasellar tumors

The objective of the present study was investigation of the possible role of proton magnetic resonance spectroscopy (¹H-MRS) for differential diagnosis of suprasellar tumors. Forty patients (23 men and 17 women; median age, 45 years) with suprasellar, hypothalamic, and third ventricle neoplasms underwent long-echo (TR: 2000 ms, TE: 136 ms, 128-256 acquisitions) single-voxel ¹H-MRS before surgical treatment. The volume of the voxel was either 3.4 cc or 8 cc. Spectroscopic data were analyzed by calculation of the various metabolite ratios as well as by determination of the type of the pathological ¹H-MR spectra. There were 19 pituitary adenomas, 7 gliomas, 5 craniopharyngiomas, 3 chordomas, meningioma, hemangiopericytoma, malignant lymphoma, germinoma, Rathke cleft cyst, and hypothalamic hamartoma (one of each). Six tumors were recurrent after initial surgical resection with or without irradiation. Comparison of the individual metabolite ratios revealed only few subtle differences among neoplasms. In the same time, pattern analysis with determination of the type of the pathological ¹H-MR spectra disclosed certain specific characteristics, which seemingly can be used for tumor typing. Meanwhile, metabolic imaging was less effective for characterization of recurrent neoplasms. In conclusion, in cases of initially diagnosed suprasellar tumors with involvement of the hypothalamus and extension into the third ventricle pattern analysis of the single-voxel ¹H-MRS can provide valuable information, which, in addition to structural MRI, can be effectively used for diagnostic purposes.