title: Apparent Diffusion Coefficient Measurement in Mediastinal Lymphadenopathies: Differentiation between Benign and Malignant Lesions.
abstract: OBJECTIVE
  We aimed to prospectively assess the diagnostic value of apparent diffusion coefficient (ADC) measurement in the differentiation of benign and malignant mediastinal lymphadenopathies.
  
  
  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 mm2/s before mediastinoscopy and mediastinotomy, and ADC values were measured. The ADC values were compared with the histological results, and statistical analysis was done.P< 0.05 was considered statistically significant.
  
  
  RESULTS
  The mean ADC value of malignant mediastinal lymphadenopathy (1.030 ± 0.245 × 10-3mm2/s) was significantly lower (P< 0.05) when compared to benign lymphadenopathies (1.571 ± 0.559 × 10-3mm2/s). For differentiating malignant from benign mediastinal lymphadenopathy, the best result was obtained when an ADC value of 1.334 × 10-3mm2/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.
authors.affiliation: Department of Radiology, Cerrahpasa Faculty of Medicine, Istanbul University, K.M. Pasa, Istanbul, Turkey.
authors.forename: Fethi Emre
authors.initials: FE
authors.lastname: Ustabasioglu
authors.affiliation: Department of Radiology, Cerrahpasa Faculty of Medicine, Istanbul University, K.M. Pasa, Istanbul, Turkey.
authors.forename: Cesur
authors.initials: C
authors.lastname: Samanci
authors.affiliation: Department of Radiology, Cerrahpasa Faculty of Medicine, Istanbul University, K.M. Pasa, Istanbul, Turkey.
authors.forename: Deniz
authors.initials: D
authors.lastname: Alis
authors.affiliation: Department of Internal Medicine, Haseki Research and Training Hospital, Haseki, Istanbul, Turkey.
authors.forename: Nilay Sengul
authors.initials: NS
authors.lastname: Samanci
authors.affiliation: Department of Radiology, Cerrahpasa Faculty of Medicine, Istanbul University, K.M. Pasa, Istanbul, Turkey.
authors.forename: Osman
authors.initials: O
authors.lastname: Kula
authors.affiliation: Department of Radiology, Cerrahpasa Faculty of Medicine, Istanbul University, K.M. Pasa, Istanbul, Turkey.
authors.forename: Deniz Cebi
authors.initials: DC
authors.lastname: Olgun
keywords: Apparent diffusion coefficient; diffusion; lymph node; magnetic resonance imaging; mediastinum