The role of apparent diffusion coefficient in differentiating typical from atypical meningioma

Background: Differentiation of typical from atypical meningiomas would greatly improve surgical planning and further treatment options. Appparent diffusion coefficient (ADC) has the potential to characterize meningioma subtypes. This study aimed to assess the value of ADC in differentiating typical and atypical meningiomas. Method: A retrospective study was conducted using medical records at RSUD Dr. Soetomo Surabaya in January 2019 – September 2021. ADC values ​were obtained by placing three ROIs on tumors. We used receiver operating curve (ROC) analysis to determine the optimal cut-off ADC value to differentiate meningioma grading and Mann-Whitney U test to evaluate the difference in ADC values ​between the two groups. In addition, Chi-square was used to assess the correlation between ADC values ​and the type of meningioma. Results: The ADC values ​in typical meningiomas ranged from 1.12-2.47 × 10^-3 mm²/s with an average of 1.45 ± 0.38 × 10^-3 mm²/s, while ​in atypical meningiomas ranged from 0.64 – 1.12 × 10^-3 mm²/s with an average of 0.81 ± 0.20 × 10^-3 mm²/s. Based on ROC analysis to distinguish typical and atypical meningiomas, the cut-off mean ADC value is 1.12 × 10^-3 mm²/s with a sensitivity of 100%, specificity of 96.87%, and area under the curve (AUC) of 0.996. The cut-off difference in the ADC value and the relationship between the ADC value and meningioma type based on histopathology were significant. Conclusion: Typical meningiomas have higher ADC values ​than atypical cases. ADC value can help differentiate typical from atypical meningiomas.