title: Effects of Iterative Reconstruction Algorithms on Computer-assisted Detection (CAD) Software for Lung Nodules in Ultra-low-dose CT for Lung Cancer Screening.
abstract: This study aimed to evaluate the effects of iterative reconstruction (IR) algorithms on computer-assisted detection (CAD) software for lung nodules in ultra-low-dose computed tomography (ULD-CT) for lung cancer screening.
  
  
  
  We selected 85 subjects who underwent both a low-dose CT (LD-CT) scan and an additional ULD-CT scan in our lung cancer screening program for high-risk populations. The LD-CT scans were reconstructed with filtered back projection (FBP; LD-FBP). The ULD-CT scans were reconstructed with FBP (ULD-FBP), adaptive iterative dose reduction 3D (AIDR 3D; ULD-AIDR 3D), and forward projected model-based IR solution (FIRST; ULD-FIRST). CAD software for lung nodules was applied to each image dataset, and the performance of the CAD software was compared among the different IR algorithms.
  
  
  
  The mean volume CT dose indexes were 3.02 mGy (LD-CT) and 0.30 mGy (ULD-CT). For overall nodules, the sensitivities of CAD software at 3.0 false positives per case were 78.7% (LD-FBP), 9.3% (ULD-FBP), 69.4% (ULD-AIDR 3D), and 77.8% (ULD-FIRST). Statistical analysis showed that the sensitivities of ULD-AIDR 3D and ULD-FIRST were significantly higher than that of ULD-FBP (P < .001).
  
  
  
  The performance of CAD software in ULD-CT was improved by using IR algorithms. In particular, the performance of CAD in ULD-FIRST was almost equivalent to that in LD-FBP.
authors.affiliation: Department of Computational Diagnostic Radiology and Preventive Medicine, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. Electronic address: nomuray-tky@umin.ac.jp.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Nomura
authors.affiliation: Department of Diagnostic Radiology, Institute and Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Higaki
authors.affiliation: Department of Diagnostic Radiology, Institute and Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan; Department of Diagnostic Radiology, Hiroshima General Hospital of West Japan Railway Company, Hiroshima, Japan.
authors.forename: Masayo
authors.initials: M
authors.lastname: Fujita
authors.affiliation: Department of Computational Diagnostic Radiology and Preventive Medicine, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
authors.forename: Soichiro
authors.initials: S
authors.lastname: Miki
authors.affiliation: Miyoshi Central Hospital, Hiroshima, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Awaya
authors.affiliation: Miyoshi Central Hospital, Hiroshima, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Nakanishi
authors.affiliation: Department of Computational Diagnostic Radiology and Preventive Medicine, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
authors.forename: Takeharu
authors.initials: T
authors.lastname: Yoshikawa
authors.affiliation: Department of Computational Diagnostic Radiology and Preventive Medicine, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
authors.forename: Naoto
authors.initials: N
authors.lastname: Hayashi
authors.affiliation: Department of Diagnostic Radiology, Institute and Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Awai
mesh_terms: D000368:Aged; D000465:Algorithms; D054893:Cone-Beam Computed Tomography; D055088:Early Detection of Cancer / Q000379:methods; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D055613:Multiple Pulmonary Nodules / Q000000981:diagnostic imaging*; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods; D011877:Radionuclide Imaging; D012984:Software; D014057:Tomography, X-Ray Computed / Q000379:methods
keywords: Computer-assisted detection (CAD); iterative reconstruction; lung nodule; ultra-low-dose CT