Objective: The purpose of this study was to determinate the contribution of diffusion-weighted (DW) magnetic resonance imaging (MRI) to the differentiation of atypical and typical meningiomas and to the determination of histological subtypes of typical meningiomas.

Materials and Methods: Fourteen patients (age range between 37-77) with meningiomas were included to this study. Using routine MRI sequences, meningiomas were diagnosed and DW images were performed using factor of b-0 and b-1000. Apparent diffusion coefficient (ADC) values were measured in the lesion, normal area of parenchyma and peritumoral edema. Student t-test was used for statistical analysis. P<0.05 was considered significant.

Results: ADC value of atypical case was 0.27x10^-3 mm²/sec. This value was lower than ADC values of typical meningiomas and normal parenchymal area. Mean ADC value of typical cases was 1.08x10^-3 mm²/sec. The difference between the subtypes of typical meningiomas was insignificant. Also, the difference between ADC values of peritumoral edema and lesions was insignificant. ADC values of typical meningiomas were higher than ADCvalues of normal area and these values were statistically significant.

Conclusion: Typical meningiomas had higher ADC values than atypical case. DW MRI may be contribute to difference between typical and atypical meningiomas.