Evaluation of the relationship of magnetic resonance spectroscopy (MRS) findings with histopathological results in glial tumors

Evaluation of the Relationship of Magnetic Resonance Spectroscopy (MRS) Findings with Histopathological Results in Glial Tumors Objective: In this study, we aimed to evaluate the effectiveness of single voxel (SV) MRS in predicting low-high grade discrimination and IDH mutation status in glial tumors. Materials and methods: Adult patients who were referred to our department with suspected brain tumor and performed SV MRS between January 2015-March 2019 were evaluated retrospectively. Totally 49 patients who were diagnosed as glial tumor and whose IDH mutation status determined were included in the study. Patients were grouped as 'low-high grade' and 'IDH mutant-IDH wild type. NAA/Cr, Cho/Cr, Cho/NAA, mI/Cr ratios were measured and lactate peak was evaluated. Results: 34 patients (69.4%) were male and 15 patients (30.6%) were female. The age of the patients ranged from 23 to 79 years and the mean age was 55.8 ± 14.7. 12 patients (24.5%) were diagnosed as low-grade and 37 patients (75.5%) were diagnosed as high-grade glial tumors. Forty-nine patients grouped according to IDH wild-mutant type characteristics without distinction of high or low grade; 14 patients (28.6%) were identified IDH mutant type and 35 patients (71.4%) were identified IDH wild type glial tumor. Cho/Cr and Cho/NAA ratios were different between low-grade and high-grade tumors(p <0.001). Area under the curve as calculated with ROC analysis was 0,914 [0,799-0,975] and 0,846 [0,714-0,933] for Cho/Cr and Cho/NAA respectively. The mI/Cr ratio was relatively high in low-grade glial tumors. There was a significant difference for lactate peak between the high-grade and the low-grade group (p <0.001). Only Cho / Cr values were significantly different between IDH mutant and wild type (p = 0.003). When the ROC curve for the Cho / Cr ratio was plotted, the area under the curve was calculated 0.776 [0.634-0.882]. Conclusion: SV MRS is a valuable non-invasive imaging modality that can be used to differentiate between low-high grade glial tumors and predict IDH mutation status. Key words: MR spectroscopy, glial tumor, brain tumors, grade, IDH mutation.