Role of MRI Apparent Diffusion Coefficient Quantification in the Differentiation between Benign and Malignant Mediastinal and Pulmonary Lesions

Objective: The purpose of the study is to evaluate the role of diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) value in the differentiation between benign and malignant mediastinal and pulmonary lesions. Patients and Methods: Twenty-nine patients with different chest and mediastinal lesions were included in this study. DW MR imaging was performed in the transverse plane with p-values of 1000 and 0sec/mm2. Apparent diffusion coefficient (ADC) maps were reconstructed and ADC value was calculated on these maps. A receiver operating curve (ROC) was drawn to detect the cutoff point used to differentiated malignancy from benign lesion with calculation of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Results: On histopathological bases, the 29 cases were subdivided to 12 benign and 17 malignant lesions. The mean ADCs of malignant and benign lesions were 1.03x10-3mm2/s and 1.8x10-3mm2/s, respectively. The mean ADC for the malignant group was significantly lower than that for the benign group (p=0.002). Using ADC value of 1.18x10-3 mm2/s as the cut-off threshold for the differentiation between benign and malignant lesions the sensitivity, specificity, PPV and NPP were 93.3% and 88.6%, 82.4% and 91.7% respectively. Conclusion: Our data suggest that diffusion weighted MRI with measurement of ADC value is very helpful in the differentiation between malignant and benign lesions of the chest and mediastinum.