Artikel
Evaluation of MR-spectroscopy differences between Oligodendrogliomas and Astrocytoma
Unterschiede in der MR-Spektroskopie zwischen Oligodendrogliomen und Astrozytomen
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Veröffentlicht: | 8. Mai 2006 |
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Gliederung
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Objective: New therapeutic options for low grade gliomas with radiation and chemotherapy show promising results. In particular chemotherapy of oligodendrogliomas is no longer restricted to anaplastic tumors. We evaluated the reliability of non invasive 1H-spectroscopy in the differentiation of oligodendrogliomas from astrocytomas and mixed gliomas. Secondly the differentiation of grade II and grade III tumors was evaluated.
Methods: 38 patients (m/f; 20/18), with non-necrotic gliomas were examined in a 1.5 T MR-Scanner (Symphony Sonata; Siemens) with multivoxel chemical shift imaging (TR/TE: 1450/135 ms). Oligodendroglioma grade II/III n=6/1, astrocytoma grade II/III n=10/14, mixed gliomas grade II/III n=4/3. Radios of the median N-acetyl-aspartat (NAA) concentration in relation to Creatin (Cr) und Cholin (Cho) concentrations were calculated in the tumor center. Statistical significance was set as p<0,05.
Results: Significant differences were found between the NAA/Cho-ratios of oligodendrogliomas and the astrocytomas and mixed gliomas (median: 0,69 vs. 0,39; p=0,02). The ratio of NAA/Cr did not reveal significant differences (Median: 0,94 vs. 0,65; p=0,06). In addition we were able to differentiate between grade II and grade III tumors using the NAA/Cr ratio (0,41 vs. 0,89; p=0,01) whereas the NAA/Cho ratio revealed no significant difference (0,51 vs. 0,34; p=0,06).
Conclusions: A differentiation between tumors of oligodendroglial and astroglial origion was possible using non invasive 1H-MR-spectroscopy, in particular the NAA/Cho ratio. Furthermore the NAA/Cr ratio may lead to a non-invasive grading tool. Therefore in the near future therapeutic decisions may be made based on MR data rather than on histology in particular in cases of tumor progression from a low grade glioma to a more malignant type.