title: Role of baseline nodule density and changes in density and nodule features in the discrimination between benign and malignant solid indeterminate pulmonary nodules.
abstract: OBJECTIVE
  To retrospectively evaluate whether baseline nodule density or changes in density or nodule features could be used to discriminate between benign and malignant solid indeterminate nodules.
  
  
  METHODS
  Solid indeterminate nodules between 50 and 500 mm(3) (4.6-9.8mm) were assessed at 3 and 12 months after baseline lung cancer screening (NELSON study). Nodules were classified based on morphology (spherical or non-spherical), shape (round, polygonal or irregular) and margin (smooth, lobulated, spiculated or irregular). The mean CT density of the nodule was automatically generated in Hounsfield units (HU) by the Lungcare software.
  
  
  RESULTS
  From April 2004 to July 2006, 7310 participants underwent baseline screening. In 312 participants 372 solid purely intra-parenchymal nodules were found. Of them, 16 (4%) were malignant. Benign nodules were 82.8mm(3) (5.4mm) and malignant nodules 274.5mm(3) (8.1mm) (p=0.000). Baseline CT density for benign nodules was 42.7 HU and for malignant nodules -2.2 HU (p=ns). The median change in density for benign nodules was -0.1 HU and for malignant nodules 12.8 HU (p<0.05). Compared to benign nodules, malignant nodules were more often non-spherical, irregular, lobulated or spiculated at baseline, 3-month and 1-year follow-up (p<0.0001). In the majority of the benign and malignant nodules there was no change in morphology, shape and margin during 1 year of follow-up (p=ns).
  
  
  CONCLUSIONS
  Baseline nodule density and changes in nodule features cannot be used to discriminate between benign and malignant solid indeterminate pulmonary nodules, but an increase in density is suggestive for malignancy and requires a shorter follow-up or a biopsy.
authors.affiliation: Department of Diagnostic and Interventional Radiology, Shanghai Sixth People's Hospital, Shanghai Jiao Tong University, 600 Yi Shan Road, PO Box 200233, Shanghai, China. dongming1996@hotmail.com
authors.forename: Dong Ming
authors.initials: DM
authors.lastname: Xu
authors.forename: Rob J
authors.initials: RJ
authors.lastname: van Klaveren
authors.forename: Geertruida H
authors.initials: GH
authors.lastname: de Bock
authors.forename: Anne L M
authors.initials: AL
authors.lastname: Leusveld
authors.forename: Monique D
authors.initials: MD
authors.lastname: Dorrius
authors.forename: Yingru
authors.initials: Y
authors.lastname: Zhao
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Harry J
authors.initials: HJ
authors.lastname: de Koning
authors.forename: Ernst T
authors.initials: ET
authors.lastname: Scholten
authors.forename: Johny
authors.initials: J
authors.lastname: Verschakelen
authors.forename: Mathias
authors.initials: M
authors.lastname: Prokop
authors.forename: Matthijs
authors.initials: M
authors.lastname: Oudkerk
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods*; D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008175:Lung Neoplasms; D008297:Male; D008875:Middle Aged; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*