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PT  - JOURNAL ARTICLE
AU  - Majós, C.
AU  - Aguilera, C.
AU  - Alonso, J.
AU  - Julià-Sapé, M.
AU  - Castañer, S.
AU  - Sánchez, J.J.
AU  - Samitier, Á.
AU  - León, A.
AU  - Rovira, Á.
AU  - Arús, C.
TI  - Proton MR Spectroscopy Improves Discrimination between Tumor and Pseudotumoral Lesion in Solid Brain Masses
AID  - 10.3174/ajnr.A1392
DP  - 2009 Mar 01
TA  - American Journal of Neuroradiology
PG  - 544--551
VI  - 30
IP  - 3
4099  - http://www.ajnr.org/content/30/3/544.short
4100  - http://www.ajnr.org/content/30/3/544.full
SO  - Am. J. Neuroradiol.2009 Mar 01; 30
AB  - BACKGROUND AND PURPOSE: Differentiating between tumors and pseudotumoral lesions by conventional MR imaging may be a challenging question. This study aims to evaluate the potential usefulness and the added value that single-voxel proton MR spectroscopy could provide on this discrimination.MATERIALS AND METHODS: A total of 84 solid brain lesions were retrospectively included in the study (68 glial tumors and 16 pseudotumoral lesions). Single-voxel spectra at TE 30 ms (short TE) and 136 ms (long TE) were available in all cases. Two groups were defined: “training-set” (56 cases) and “test-set” (28 cases). Tumors and pseudotumors were compared in the training-set with the Mann-Whitney U test. Ratios between resonances were defined as classifiers for new cases, and thresholds were selected with receiver operating characteristic (ROC) curves. The added value of spectroscopy was evaluated by 5 neuroradiologists and assessed with the Wilcoxon signed-rank test.RESULTS: Differences between tumors and pseudotumors were found in myo-inositol (mIns); P &amp;lt; .01) at short TE, and N-acetylaspartate (NAA; P &amp;lt; .001), glutamine (Glx; P &amp;lt; .01), and choline (CHO; P &amp;lt; .05) at long TE. Classifiers suggested tumor when mIns/NAA ratio was more than 0.9 at short TE and also when CHO/NAA ratio was more than 1.9 at long TE. Classifier accuracy was tested in the test-set with the following results: short TE, 82% (23/28); long TE, 79% (22/28). The neuroradiologists’ confidence rating of the test-cases on a 5-point scale (0–4) improved between 5% (from 2.86–3) and 27% (from 2.25–2.86) with spectroscopy (mean, 17%; P &amp;lt; .01).CONCLUSIONS: The proposed ratios of mIns/NAA at short TE and CHO/NAA at long TE provide valuable information to discriminate between brain tumor and pseudotumor by improving neuroradiologists’ accuracy and confidence.