NIMG-56. MAGNETIC RESONANCE SPECTROSCOPY IN THE POST-TREATMENT METABOLIC CHARACTERIZATION OF BRAIN TUMORS OF GLIAL ORIGIN OF CENTRAL NERVOUS SYSTEM

Abstract BACKGROUND and Purpose Central Nervous System tumors have a very low incidence worldwide, however they constitute an important source of mortality and morbidity. Treatment for these types of tumors in adults may include surgery, radiosurgery, radiation therapy, chemotherapy, and targeted treatment. These treatments in brain tumors of glial origen in adults can produce changes in the pathophysiology of the tumor. The purpose of this study was to characterize the different metabolic patterns as effect of treatment and identify tumor recurrences. Materials and METHODS A prospective study was conducted with patients with low- and high-grade tumors treated, subjecting them to the single-voxel MRS and multivoxel MRSI protocol at 1.5 T. RESULTS Of the 44 patients included, 21 were histopathologically diagnosed as low-grade tumors and 23 as high-grade tumors. Of the low-grade tumors, 11 were caracterized as low-grade (mean Cho/NAA and NAA/Cr ratios 1.49 ((p=0.036) and 0.92 (p=0.038) respectively), 8 cases presented gliosis (mean Cho/NAA and NAA/Cr ratios 1.57 (p=0.028) and 1.36 (p=0.026) respectively), and 4 cases presented radiation necrosis (mean Cho/Cr ratios 2.14 (p=0.03)), (mean Cho/Cr and NAA/Cr ratios 1.25 (p=0.01) and 1.25 (p=0.00)) respectively). Furthermore, tumor recurrence that presented high Cho/NAA ratio were observed in 11 cases. Of the high-grade tumors, 13 were caracterized as high-grade (mean Cho/NAA and Cho/Cr ratios 2.24 (p=0.026) and 4.48 (p=0.026) respectively), 13 cases presented gliosis (mean Cho/NAA and NAA/Cr ratios 1.82 (p=0.028) and 0.64 (p=0.026)) respectively) and radiation necrosis was detected in 10 cases (mean Cho/Cr ratio 1.47 (p=0.03), (mean Cho/Cr and NAA/Cr ratios 2.25 (p=0.01) and 0.97 (p=0.00) respectively). Moreover, tumor recurrence that presented high Cho/NAA ratio were observed in 9 cases. CONCLUSION MRS and MRSI contribute to identifying the recurrences, to characterizing the different metabolic patterns as an effect of the treatment and differentiate between low and high grade tumors.