title: Metastases in mediastinal and hilar lymph nodes in patients with non-small cell lung cancer: quantitative assessment with diffusion-weighted magnetic resonance imaging and apparent diffusion coefficient.
abstract: OBJECTIVE
  To evaluate diffusion-weighted magnetic resonance (DW-MR) imaging for detection of metastases in lymph nodes by using quantitative analysis.
  
  
  METHODS
  Seventy patients with non-small cell lung cancer were examined with DW and short inversion time inversion recovery (STIR) turbo-spin-echo MR imaging. Apparent diffusion coefficient of each lung cancer and lymph node was calculated from DW-MR images. Difference of the apparent diffusion coefficient in a lung cancer and a lymph node was calculated (D1). From STIR turbo-spin-echo MR images, ratios of signal intensity in a lymph node to that in a 0.9% saline phantom was calculated (lymph node-saline ratio [LSR1]). For quantitative analysis, the threshold value for a positive test was determined on a per node basis and tested for ability to enable a correct diagnosis on a per patient basis. Results of quantitative analyses of DW- and STIR-MR images were compared on a per patient basis with McNemar testing.
  
  
  RESULTS
  Mean D1 in the lymph node group with metastases was lower than that in the group without metastases (P < 0.001). When an D1 of 0.24 x 10(-3) mm2/s was used as the positive test threshold, sensitivity, specificity, and accuracy were 69.2%, 100%, and 94.0%, respectively, on a per patient basis. There was no significant difference (P > 0.05) between quantitative analyses of DW-MR images and STIR-MR images.
  
  
  CONCLUSIONS
  Quantitative analysis of DW-MR images enables differentiation of lymph nodes with metastasis from those without.
authors.affiliation: Medical Image Lab, Inc., Hokkaido University Hospital, Kita-ku, Saporo, Japan. jnakaj@nifty.com
authors.forename: Jun
authors.initials: J
authors.lastname: Nakayama
authors.forename: Kazuo
authors.initials: K
authors.lastname: Miyasaka
authors.forename: Tokuhiko
authors.initials: T
authors.lastname: Omatsu
authors.forename: Yuuya
authors.initials: Y
authors.lastname: Onodera
authors.forename: Satoshi
authors.initials: S
authors.lastname: Terae
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Matsuno
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Cho
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Hida
authors.forename: Kichizo
authors.initials: K
authors.lastname: Kaga
authors.forename: Hiroki
authors.initials: H
authors.lastname: Shirato
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000556:secondary / Q000601:surgery; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology* / Q000556:secondary* / Q000601:surgery; D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000556:secondary / Q000601:surgery; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology* / Q000601:surgery; D008197:Lymph Node Excision / Q000379:methods; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis; D008297:Male; D008482:Mediastinum / Q000473:pathology*; D008875:Middle Aged; D019047:Phantoms, Imaging; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity