title: Diffusion-weighted MR imaging of mediastinal lymphadenopathy in children.
abstract: OBJECTIVE
  To assess mediastinal lymphadenopathy in children with diffusion-weighted MR imaging.
  
  
  METHODS
  Retrospective analysis of 29 consecutive children (18 boys and 11 girls aged 2-15 years) with mediastinal lymphadenopathy. They underwent single-shot echo planar diffusion-weighted MR imaging of the mediastinum with b factors of 0, 300, and 600 s/mm(2). The ADC value of the mediastinal lymph nodes was calculated and correlated with biopsy results; statistical analysis was also performed.
  
  
  RESULTS
  The mean ADC value for malignant mediastinal lymphadenopathy (n = 20) (0.99 ± 0.18 × 10(-3) mm(2)/s) was significantly lower (P = 0.001) than that for benign lymphadenopathy (n = 9) (1.35 ± 0.26 × 10(-3) mm(2)/s). There was significant difference between ADC values for non-Hodgkin lymphoma and metastatic nodes (P = 0.04). For differentiating malignant from benign mediastinal lymphadenopathy, the best result was obtained when an ADC value of 1.22 × 10(-3) mm(2)/s was used as a threshold value; area under the curve was 0.861, accuracy 93.1 %, sensitivity 100 %, specificity of 77.8 %, positive predictive value 90.9 %, and negative predictive value of 100 %.
  
  
  CONCLUSIONS
  Diffusion-weighted MR imaging is a promising non-invasive imaging modality that can be used for differentiation of malignant from benign mediastinal lymphadenopathy in children.
authors.affiliation: Department of Diagnostic Radiology, Mansoura Faculty of Medicine, Mansoura, DK, 13351, Egypt, arazek@mans.edu.eg.
authors.forename: Ahmed Abdel Khalek
authors.initials: AA
authors.lastname: Abdel Razek
authors.forename: Ghada
authors.initials: G
authors.lastname: Gaballa
authors.forename: Rasha
authors.initials: R
authors.lastname: Elashry
authors.forename: Sahar
authors.initials: S
authors.lastname: Elkhamary
mesh_terms: D000293:Adolescent; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008297:Male; D008477:Mediastinal Diseases / Q000175:diagnosis; D008479:Mediastinal Neoplasms / Q000175:diagnosis*; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity