The role of advanced magnetic resonance imaging in the differential diagnosis of glial tumor-metastatic tumor

Aim: Our aim in this study was to investigate the efficacy of advanced MRI findings in grading primary glial tumors and differentiating them from brain metastases and to contribute to the literature. Materials and methods: The study was conducted with a total of 131 patients with pathological diagnosis of glial brain tumor and brain metastasis, who underwent preoperative MR imaging in our center between January 2012 and January 2024, and underwent at least two of the DAG, MRS and MRP advanced examinations. Age, gender, pathologic diagnosis, primary malignancy diagnosis for the brain metastasis group, IDH mutation and Ki-67 proliferation index ratio were recorded from the patient file. The degree of tumor contrast enhancement, presence of T2/FLAIR mismatch on conventional MRI, minimum ADC (10^-3mm2/sec) value and ADC ratio on DAG, rCBV value on DSC perfusion, Ktrans and Ve values on DCE perfusion, LL, MI levels and Ch/NAA, Ch/Cr ratios on MRS were evaluated. Results: Statistically significant differences were found between the groups in tumoral and peritumoral ADC values and ratios in diffusion weighted imaging, tumoral and peritumoral rCBV values in DSC perfusion, Ktrans and Ve values in DCE perfusion, Ch/Cr, LL and MI values in short TE (35 ms), LL and Ch/Cr values in medium TE (144 ms) in MR spectroscopy. In glial tumor cases, there was a statistically significant negative correlation between Ki 67 proliferation index and tumor minimum ADC value, and a positive correlation between Ki 67 proliferation index and tumor rCBV (centrum semiovale) value. Conclusion: In the evaluation of brain tumors, the combination of conventional MRI findings with diffusion MRI, perfusion MRI and MR spectroscopy imaging findings increases the diagnostic accuracy in the differential diagnosis of lesions. The contribution of preoperative advanced MRI imaging to the diagnosis will be better understood with prospective studies with larger case groups. Key words: Brain tumor, glial tumor, brain metastasis, diffusion weighted MRI, perfusion MRI, MR spectroscopy imaging