Relationship between Edema Index in MRI and Histopathological Grading of Intracranial Meningioma

Background: Meningiomas are common primary intracranial tumors, classified into three grades and 15 subtypes by the 2016 WHO classification.Though extra-axial, these tumors often show peritumoral brain edema (PTBE).The edema index (EI), from MRI measurements, indicates edema severity.Understanding the relationship between EI and histopathological grading may improve preoperative assessment and treatment planning.This study evaluated the relationship between edema index on MRI and histopathological grading of intracranial meningiomas.Methods: This cross-sectional study included 30 patients with confirmed intracranial meningiomas at Bangladesh Medical University, Dhaka, from September 2022 to October 2024.MRI with contrast determined tumor and FLAIR image determined edema volumes, with EI calculated as (tumor + edema volume)/tumor volume.Data analysis was conducted using SPSS version 26.Results: Participants' mean age was 47.9 ± 11.6 years, with females predominating (76.7%) at a ratio of 3.2:1.Tumors were mainly supratentorial (56.7%), followed by skull base (30%) and infratentorial (13.3%).Among Grade I meningiomas (n=23), 69.6% had EI ≤ 2.0, while 30.4% had EI > 2.0.For Grade II tumors (n=7), 71.4% showed EI > 2.0, indicating more extensive peritumoral edema.Mean EI was significantly higher in Grade II versus Grade I meningiomas (p = 0.0045).A positive correlation between EI and tumor grade suggested that higher edema indices are associated with more aggressive histological features.Conclusion: Higher edema index correlates with increased histopathological grade in intracranial meningiomas, indicating its value as a preoperative radiological marker for surgical planning.