Objective: The aim of this study was to evaluate the ability of diffusion weighted magnetic resonance imaging (dMRI) in differentiating transudate pleural effusions from exudate pleural effusions with asbestos-related pleural diseases.

Material and Method: This study included 55 patients. Thirty-three had a benign form of the disease and 22 had malignant pleural mesothelioma (MPM). The patient files and records belonging to ones who underwent dMRI on a 1.5 T MR system between January 2015 and February 2016 in our clinic were examined retrospectively. The dMRI was done with b values of 0,500 and 1000 s/mm². The apparent diffusion coefficient (ADC) maps were generated and mean ADC values were measured from pleural effusions.

Results: Appropriate ADC maps were obtained in 55 patients. The mean pleural effusion ADC values were 3.61 ± 0.55 x 10^-3 mm²/s in benign pleural disease and 3.12 ± 0.62 x 10^-3 mm²/s in MPM, respectively. The optimum cutoff point for ADC values was 3.43 x 10-3 mm²/s with a sensitivity of 88.6% and specificity of 84%. The mean ADC value of the effusions in malignant mesothelioma was significantly lower than that of benign pleural disease (p < 0.05).

Conclusion: dMRI may help in the differential diagnosis of transudate and exudate pleural effusions that indicate to early detection of MPM with asbestos-related pleural diseases.