1-H MR Spectroscopy in Grading of Cerebral Gliomas Using Short and Intermediate Echo Time Sequences

Purpose: The aim of this study was to determine the diagnostic value of short and intermediate TEs in determining the grade of cerebral glioma with reference to operative and histopathological results whenever possible. Material and Methods: Thirty-one patients (21 males and 10 females), ranging in age from 15-63 years (mean 34.4 years) were prospectively recruited for this study. All had a brain tumor recently diagnosed by MRI and had received no previous treatment, except for steroids. They were referred for MRS examination before surgical biopsy and/or resection or radiotherapy. MI level and MI/Cr ratio were obtained for each lesion and compared with the grade of the lesion. Results: The levels of MI/Cr were higher (1.89±1.27) in patients with low-grade astrocytoma, and lower in patients with anaplastic astrocytoma (0.35±0.11) and GBM (0.04±0.07). Thirty out of the thirty-one patients were correctly classified using MI/Cr ratio; one patient was misdiagnosed as high-grade glioma and the biopsy revealed grade II glioma. The diagnostic accuracy, sensitivity and specificity of MI/Cr ratio for the grading of glioma was 96.7%, 100%, and 95%, respectively. Conclusion: MRS has proven to be an important complementary tool in diagnosing and grading gliomas, saving the patient from unnecessary biopsy taking when it is conclusive thus altering the treatment planning. This study had demonstrated that MI level, MI/Cr ratio as well as, lipid lactate peaks are important in presurgical grading of brain tumors.