title: Incremental value of contrast enhanced computed tomography on diagnostic accuracy in evaluation of small pulmonary ground glass nodules.
abstract: BACKGROUND
  To evaluate the information gain by the application of both non-contrast and contrast enhanced computed tomography (CT) with extended mediastinal display window settings in the evaluation of pure ground glass nodules (pGGNs) and or mixed ground glass nodules (mGGNs) in the context of pre-invasive or early stage lung adenocarcinoma.
  
  
  METHODS
  One hundred and fifty patients with ground glass nodules (GGNs) and mGGNs, with contrast enhanced CT scans within 2 weeks of thoracic surgery were included in the study. Quantitative evaluation of all nodules was performed in a conventional mediastinal window (CMW) and an extended mediastinal window (EMW) both on non-contrast images and contrast-enhanced images.
  
  
  RESULTS
  Contrast-enhanced images with CMW demonstrated amplification of solid portion in 23 (43%), 41 (77%) with EMW out of 53 minimally invasive adenocarcinoma (MIA) nodules, and in 34 of 37 (91%) of invasive adenocarcinoma (IAC) nodules. Using the increase in size of solid portion of the nodule measured on the enhanced CT images with EMW, area under the receiver operating characteristic (ROC) curve of 0.872 and 0.899 was utilized for differentiating between the pre-invasive nodules and MIA and between MIA and IAC nodules, respectively. Statistically significant differences existed between the pre-invasive and the MIA groups, and MIA and the IAC groups in smaller nodules (P<0.01).
  
  
  CONCLUSIONS
  Comparative quantitative analysis of the pre and post contrast images can help differentiate between atypical adenomatous hyperplasia (AAH), adenocarcinoma in situ (AIS), MIAs, and IACs. Extension of the CT mediastinal window setting improves the evaluation of small GGNs, and can augment the diagnostic accuracy when evaluating small pGGNs and mGGNs.
authors.affiliation: 1 Department of Radiology and Radiation Oncology, Huadong Hospital affiliated to Fudan University, Shanghai, China ; 2 Department of Radiology, Brigham and Women's Hospital affiliated to Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.affiliation: 1 Department of Radiology and Radiation Oncology, Huadong Hospital affiliated to Fudan University, Shanghai, China ; 2 Department of Radiology, Brigham and Women's Hospital affiliated to Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.affiliation: 1 Department of Radiology and Radiation Oncology, Huadong Hospital affiliated to Fudan University, Shanghai, China ; 2 Department of Radiology, Brigham and Women's Hospital affiliated to Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Jayender
authors.initials: J
authors.lastname: Jagadeesan
authors.affiliation: 1 Department of Radiology and Radiation Oncology, Huadong Hospital affiliated to Fudan University, Shanghai, China ; 2 Department of Radiology, Brigham and Women's Hospital affiliated to Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Ritu R
authors.initials: RR
authors.lastname: Gill
authors.affiliation: 1 Department of Radiology and Radiation Oncology, Huadong Hospital affiliated to Fudan University, Shanghai, China ; 2 Department of Radiology, Brigham and Women's Hospital affiliated to Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Yanqing
authors.initials: Y
authors.lastname: Hua
authors.affiliation: 1 Department of Radiology and Radiation Oncology, Huadong Hospital affiliated to Fudan University, Shanghai, China ; 2 Department of Radiology, Brigham and Women's Hospital affiliated to Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Xiangpeng
authors.initials: X
authors.lastname: Zheng
keywords: Lung adenocarcinoma; X-ray computed; enhancement; ground glass nodules (GGNs); tomography; window width/window level