title: New CT criteria for nodal staging in non-small cell lung cancer.
abstract: OBJECTIVE
  The purpose of our study was to develop a simple noninvasive technique for nodal staging using routine preoperative computed tomography (CT).
  
  
  METHODS
  The institutional review board approved this retrospective study, and written informed consent to perform the initial and follow-up CT studies was obtained from all patients. Preoperative CT findings (n=218 patients with resectable non-small cell lung cancer) and pathological diagnoses after surgical resection were evaluated. Using CT images, lymph node section area, circumference, and lesion attenuation values (LAVs) were drawn freehand, and the short axis (SA) and long axis (LA) were measured using caliper software. Receiver operating characteristic (ROC) curves were then used to analyze the section area, circumference, and LAVs.
  
  
  RESULTS
  Based on ROC curves, two cut-off values, lymph node section area >30 mm(2) and circumference >25 mm, showed greater sensitivity for nodal staging than the conventional criterion of lymph node SA ≥10 mm or the LA, SA/LA ratio or LAVs. Using lymph node section area >30 mm(2) for diagnosis, the sensitivity, specificity, and accuracy of nodal staging were 90.5%, 56.3%, and 58.3%, respectively. Using lymph node circumference >25 mm, the values were 76.2%, 70.4%, and 70.8%, respectively.
  
  
  CONCLUSIONS
  Lymph node section area >30 mm(2) and circumference >25 mm can serve as supportive criteria used by radiologists and surgeons to determine nodal staging. If these CT criteria are met, use of a more sensitive procedure such as positron emission tomography or mediastinoscopy is recommended.
  CT is used routinely during preoperative management of lung cancer. Based on ROC analyses, the cut-off values for surface area, circumference, the SA/LA ratio, and LAVs for diagnosis of lymph node metastasis were 30 mm(2), 25 mm, 0.65, and 50 Hounsfield units, respectively. Our findings indicate that lymph node surface area >30 mm(2) and circumference >25 mm are supportive criteria that can be used by radiologists and thoracic surgeons to determine nodal staging and surgical indications.
authors.affiliation: Department of General Thoracic Surgery (and Breast and Endocrine Surgery), Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita City 010-8543, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kudo
authors.affiliation: Department of General Thoracic Surgery (and Breast and Endocrine Surgery), Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita City 010-8543, Japan. Electronic address: i-karo@mui.biglobe.ne.jp.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Imai
authors.affiliation: Department of Integrated Medicine, Division of Radiology and Radiation Medicine, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita City 010-8543, Japan.
authors.forename: Kouichi
authors.initials: K
authors.lastname: Ishiyama
authors.affiliation: Department of Integrated Medicine, Division of Radiology and Radiation Medicine, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita City 010-8543, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Hashimoto
authors.affiliation: Department of General Thoracic Surgery (and Breast and Endocrine Surgery), Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita City 010-8543, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Saito
authors.affiliation: Department of General Thoracic Surgery (and Breast and Endocrine Surgery), Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita City 010-8543, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Motoyama
authors.affiliation: Department of General Thoracic Surgery (and Breast and Endocrine Surgery), Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita City 010-8543, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Sato
authors.affiliation: Department of General Thoracic Surgery (and Breast and Endocrine Surgery), Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita City 010-8543, Japan.
authors.forename: Shinogu
authors.initials: S
authors.lastname: Takashima
authors.affiliation: Department of Environmental Health Sciences, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita City 010-8543, Japan.
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Murata
authors.affiliation: Department of General Thoracic Surgery (and Breast and Endocrine Surgery), Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita City 010-8543, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Minamiya
mesh_terms: D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000592:standards*
keywords: Computed tomography; Lung cancer; Lymph node; Metastasis