Diffusion weighted MRI of mediastinal masses: Can measurement of ADC value help in the differentiation betw een benign and malignant lesions

Purpose The purpose of this study is to evaluate the role of measurement of ADC value in the differentiation between benign and malignant mediastinal lesions. Patients and methods 42 patients with 52 mediastinal lesions were included in this study. They underwent diffusion weighted MRI with b values of 1000 and 0 s/mm2. ADC value measurement and histopathological diagnosis were done for each lesion. Correlation between ADC value and histopathology was done through statistical analysis. Results 32 lesions were malignant and 20 lesions were benign. The mean ADC value for the malignant lesions was significantly lower than the mean ADC value for benign lesions (P value <0.001). The mean ADC value for malignant lesions was 0.91 ± 0.23 × 10-3 mm2/s while for the benign lesions it was 1.80 ± 0.55 × 10-3 mm2/s. The cutoff point of the ADC value differentiating malignant from benign mediastinal lesions was 1.15 × 10-3 mm2/s with sensitivity of 95%, specificity of 93.8%, positive predictive value of 90.5%, and negative predictive value of 96.8% and accuracy of 94.4%. Conclusion Diffusion weighted MRI and measurement of ADC value are very helpful in the differentiation between benign and malignant mediastinal lesions.