Use of Diffusion Weighted Imaging in Differentiating Between Maligant and Benign Meningiomas. A Multicenter Analysis

Background Meningioma is the most frequent intracranial tumor and is often an incidental finding on imaging. Some imaging-based scores were suggested for differentiating low- and high-grade meningiomas. The purpose of this work was to compare diffusion-weighted imaging findings of different meningiomas in a large multicenter study by using apparent diffusion coefficient (ADC) values for predicting tumor grade and proliferation potential. Methods Data from 7 radiologic departments were acquired retrospectively. Overall, 389 patients were collected. All meningiomas were investigated by magnetic resonance imaging (1.5-T scanner) by using diffusion-weighted imaging (b values of 0 and 1000 s/mm2 ). The comparison of ADC values was performed by Mann-Whitney U test. Results World Health Organization grade I was diagnosed in 271 cases (69.7%), grade II in 103 (26.5%), and grade III in 15 patients (3.9%). Grade I meningiomas showed statistically significant higher ADC values (1.05 ± 0.39 × 10−3 mm2 s−1 ) in comparison with grade II (0.77 ± 0.15 × 10−3 mm2 s−1 ; P = 0.001) and grade III tumors (0.79 ± 0.21 × 10−3 mm2 s−1 ; P = 0.01). An ADC value of