title: Morphological factors differentiating between early lung adenocarcinomas appearing as pure ground-glass nodules measuring ≤10 mm on thin-section computed tomography.
abstract: BACKGROUND
  We aimed to compare the morphological features of pure ground-glass nodules (GGNs; diameter, ≤10 mm) on thin-section computed tomography (TSCT) with their histopathological results in order to identify TSCT features differentiating between atypical adenomatous hyperplasia (AAH), adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA).
  
  
  METHODS
  Between January and December 2013, 205 pure GGNs with a diameter ≤10 mm on TSCT were pathologically confirmed as AAH (40), AIS (95) or MIA (70) lesions. The patients' age and sex were recorded. The morphological features were evaluated, and maximum diameter and mean CT value were measured for each nodule. F test, Pearson χ2 test, Fisher exact test and multinomial logistic regression analysis were used to identify factors differentiating between AAH, AIS and MIA. Receiver operating characteristic (ROC) curve analysis was performed for maximum diameter and mean CT value.
  
  
  RESULTS
  F test, Pearson χ2 test and Fisher exact test revealed that maximum diameter (P <0.00001), mean CT value (P =0.005), type of interface (P =0.005) and presence of air bronchograms (P =0.02, n =44) significantly differed among the AAH, AIS and MIA groups. Multinomial logistic regression analysis showed that maximum diameter ≥6.5 mm, a well-defined and coarse interface indicated AIS or MIA rather than AAH; air bronchograms differentiated MIA from AAH; but these parameters did not differentiate between AIS and MIA. A mean CT value less than -520 HU indicated AAH or AIS rather than MIA, but did not differentiate between AAH and AIS.
  
  
  CONCLUSIONS
  In the case of pure GGNs measuring ≤10 mm, a maximum diameter ≥6.5 mm, a well-defined and coarse interface indicate AIS or MIA rather than AAH; an air bronchogram can differentiate MIA from AAH. A mean CT value less than -520 HU indicates AAH or AIS rather than MIA.
authors.forename: Wenjing
authors.initials: W
authors.lastname: Xiang
authors.forename: Yanfen
authors.initials: Y
authors.lastname: Xing
authors.forename: Sen
authors.initials: S
authors.lastname: Jiang
authors.forename: Gang
authors.initials: G
authors.lastname: Chen
authors.forename: Haixia
authors.initials: H
authors.lastname: Mao
authors.forename: Kanchan
authors.initials: K
authors.lastname: Labh
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Jia
authors.forename: Xiwen
authors.initials: X
authors.lastname: Sun
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000473:pathology*; D000077192:Adenocarcinoma of Lung; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D016015:Logistic Models; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D013902:Radiography, Thoracic / Q000379:methods*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*