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PT  - JOURNAL ARTICLE
AU  - Schlemmer, Heinz–Peter
AU  - Bachert, Peter
AU  - Herfarth, Klaus K.
AU  - Zuna, Ivan
AU  - Debus, Jürgen
AU  - van Kaick, Gerhard
TI  - Proton MR Spectroscopic Evaluation of Suspicious Brain Lesions After Stereotactic Radiotherapy
DP  - 2001 Aug 01
TA  - American Journal of Neuroradiology
PG  - 1316--1324
VI  - 22
IP  - 7
4099  - http://www.ajnr.org/content/22/7/1316.short
4100  - http://www.ajnr.org/content/22/7/1316.full
SO  - Am. J. Neuroradiol.2001 Aug 01; 22
AB  - BACKGROUND AND PURPOSE: The radiologic assessment of suspicious brain lesions after stereotactic radiotherapy of brain tumors is difficult. The purpose of our study was to define parameters from single-voxel proton MR spectroscopy that provide a probability measure for differentiating neoplastic from radiation-induced, nonneoplastic lesions.METHODS: Seventy-two lesions in 56 patients were examined using a combined MR imaging and MR spectroscopy protocol (point-resolved spectroscopy, TE = 135 ms). Signal intensities of cholines, creatines, N-acetyl aspartate, and the presence of lactate and lipid resonances were correlated to final diagnoses established by clinical and MR imaging follow-up, positron emission tomography studies, or biopsy/surgery. Statistical analysis was performed using the t test, linear discriminant analysis, and k nearest-neighbor method.RESULTS: Significantly increased signal intensity ratios ItCho/ItCr (P &amp;lt; .0001) and ItCho/INAA (P &amp;lt; .0001) were observed in neoplastic (n = 34) compared with nonneoplastic lesions (n = 32) and contralateral normal brain (n = 33). Analysis of ItCho/ItCr and ItCho/INAA data yielded correct retrospective classification as neoplastic and nonneoplastic in 82% and 81% of the lesions, respectively. Neither INAA/ItCr nor signal intensitities of lactate or lipids were useful for differential diagnosis.CONCLUSION: Metabolic information provided by proton MR spectroscopy is useful for the differentiation of neoplastic and nonneoplastic brain lesions after stereotactic radiotherapy of brain tumors.