title: Computer-aided detection of lung nodules via 3D fast radial transform, scale space representation, and Zernike MIP classification.
abstract: OBJECTIVE
  The authors presented a novel system for automated nodule detection in lung CT exams.
  
  
  METHODS
  The approach is based on (1) a lung tissue segmentation preprocessing step, composed of histogram thresholding, seeded region growing, and mathematical morphology; (2) a filtering step, whose aim is the preliminary detection of candidate nodules (via 3D fast radial filtering) and estimation of their geometrical features (via scale space analysis); and (3) a false positive reduction (FPR) step, comprising a heuristic FPR, which applies thresholds based on geometrical features, and a supervised FPR, which is based on support vector machines classification, which in turn, is enhanced by a feature extraction algorithm based on maximum intensity projection processing and Zernike moments.
  
  
  RESULTS
  The system was validated on 154 chest axial CT exams provided by the lung image database consortium public database. The authors obtained correct detection of 71% of nodules marked by all radiologists, with a false positive rate of 6.5 false positives per patient (FP/patient). A higher specificity of 2.5 FP/patient was reached with a sensitivity of 60%. An independent test on the ANODE09 competition database obtained an overall score of 0.310.
  
  
  CONCLUSIONS
  The system shows a novel approach to the problem of lung nodule detection in CT scans: It relies on filtering techniques, image transforms, and descriptors rather than region growing and nodule segmentation, and the results are comparable to those of other recent systems in literature and show little dependency on the different types of nodules, which is a good sign of robustness.
authors.affiliation: Department of Physics, University of Bologna, Bologna 40127, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Riccardi
authors.forename: Todor Sergueev
authors.initials: TS
authors.lastname: Petkov
authors.forename: Gianluca
authors.initials: G
authors.lastname: Ferri
authors.forename: Matteo
authors.initials: M
authors.lastname: Masotti
authors.forename: Renato
authors.initials: R
authors.lastname: Campanini
mesh_terms: D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D005189:False Positive Reactions; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D012372:ROC Curve; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*