Apparent Diffusion Coefficient Measurement in Mediastinal Lymphadenopathies: Differentiation between Benign and Malignant Lesions.

Objectives: We aimed to prospectively assess the diagnostic value of apparent diffusion coefficient (ADC) measurement in the differentiation of benign and malignant mediastinal lymphadenopathies.

Materials And Methods: The study included 63 consecutive patients (28 women, 35 men; mean age 59.3 years) with 125 mediastinal lymphadenopathies. Echoplanar diffusion-weighted magnetic resonance imaging of the mediastinum was performed with b-factors of 0 and 600 mm/s before mediastinoscopy and mediastinotomy, and ADC values were measured. The ADC values were compared with the histological results, and statistical analysis was done. < 0.05 was considered statistically significant.

Results: The mean ADC value of malignant mediastinal lymphadenopathy (1.030 ± 0.245 × 10 mm/s) was significantly lower ( < 0.05) when compared to benign lymphadenopathies (1.571 ± 0.559 × 10 mm/s). For differentiating malignant from benign mediastinal lymphadenopathy, the best result was obtained when an ADC value of 1.334 × 10 mm/s was used as a threshold value; area under the curve 0.848, accuracy 78.4%, sensitivity 66%, specificity of 86%, positive predictive value 76.7%, and negative predictive value of 79.2%. Interobserver agreement was excellent for ADC measurements.

Conclusions: ADC measurements could be considered an important supportive method in differentiating benign from malignant mediastinal lymphadenopathies.