title: Lung nodule detection on chest CT: evaluation of a computer-aided detection (CAD) system.
abstract: OBJECTIVE
  To evaluate the capacity of a computer-aided detection (CAD) system to detect lung nodules in clinical chest CT.
  
  
  METHODS
  A total of 210 consecutive clinical chest CT scans and their reports were reviewed by two chest radiologists and 70 were selected (33 without nodules and 37 with 1-6 nodules, 4-15.4 mm in diameter). The CAD system (ImageChecker CT LN-1000) developed by R2 Technology, Inc. (Sunnyvale, CA) was used. Its algorithm was designed to detect nodules with a diameter of 4-20 mm. The two chest radiologists working with the CAD system detected a total of 78 nodules. These 78 nodules form the database for this study. Four independent observers interpreted the studies with and without the CAD system.
  
  
  RESULTS
  The detection rates of the four independent observers without CAD were 81% (63/78), 85% (66/78), 83% (65/78), and 83% (65/78), respectively. With CAD their rates were 87% (68/78), 85% (66/78), 86% (67/78), and 85% (66/78), respectively. The differences between these two sets of detection rates did not reach statistical significance. In addition, CAD detected eight nodules that were not mentioned in the original clinical radiology reports. The CAD system produced 1.56 false-positive nodules per CT study. The four test observers had 0, 0.1, 0.17, and 0.26 false-positive results per study without CAD and 0.07, 0.2, 0.23, and 0.39 with CAD, respectively.
  
  
  CONCLUSIONS
  The CAD system can assist radiologists in detecting pulmonary nodules in chest CT, but with a potential increase in their false positive rates. Technological improvements to the system could increase the sensitivity and specificity for the detection of pulmonary nodules and reduce these false-positive results.
authors.affiliation: Department of Radiology, Weill Medical College of Cornell University, New York, NY, USA.
authors.forename: In Jae
authors.initials: IJ
authors.lastname: Lee
authors.forename: Gordon
authors.initials: G
authors.lastname: Gamsu
authors.forename: Julianna
authors.initials: J
authors.lastname: Czum
authors.forename: Ning
authors.initials: N
authors.lastname: Wu
authors.forename: Rebecca
authors.initials: R
authors.lastname: Johnson
authors.forename: Sanjay
authors.initials: S
authors.lastname: Chakrapani
mesh_terms: D003936:Diagnosis, Computer-Assisted; D005189:False Positive Reactions; D006801:Humans; D008171:Lung Diseases / Q000000981:diagnostic imaging*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging; D013902:Radiography, Thoracic / Q000379:methods*; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*