title: Comparative evaluation of newly developed model-based and commercially available hybrid-type iterative reconstruction methods and filter back projection method in terms of accuracy of computer-aided volumetry (CADv) for low-dose CT protocols in phantom study.
abstract: OBJECTIVE
  To directly compare the capability of three reconstruction methods using, respectively, forward projected model-based iterative reconstruction (FIRST), adaptive iterative dose reduction using three dimensional processing (AIDR 3D) and filter back projection (FBP) for radiation dose reduction and accuracy of computer-aided volumetry (CADv) measurements on chest CT examination in a phantom study.
  
  
  METHODS
  An anthropomorphic thoracic phantom with 30 simulated nodules of three density types (100, -630, and -800 HU) and five different diameters was scanned with an area-detector CT at tube currents of 270, 200, 120, 80, 40, 20, and 10mA. Each scanned data set was reconstructed as thin-section CT with three methods, and all simulated nodules were measured with CADv software. For comparison of the capability for CADv at each tube current, Tukey's HSD test was used to compare the percentage of absolute measurement errors for all three reconstruction methods. Absolute percentage measurement errors were then compared by means of Dunett's test for each tube current at 270mA (standard tube current).
  
  
  RESULTS
  Mean absolute measurement errors of AIDR 3D and FIRST methods for each nodule type were significantly lower than those of the FBP method at 20mA and 10mA (p<0.05). In addition, absolute measurement errors of the FBP method at 20mA and 10mA was significantly higher than that at 270mA for all nodule types (p<0.05).
  
  
  CONCLUSIONS
  The FIRST and AIDR 3D methods are more effective than the FBP method for radiation dose reduction, while yielding better measurement accuracy of CADv for chest CT examination.
authors.affiliation: Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan; Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan. Electronic address: yosirad@kobe-u.ac.jp.
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Ohno
authors.affiliation: Corporate Research and Development Center, Toshiba Corporation, Kawasaki, Kanagawa, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yaguchi
authors.affiliation: Corporate Research and Development Center, Toshiba Corporation, Kawasaki, Kanagawa, Japan.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Okazaki
authors.affiliation: Toshiba Medical Systems Corporation, Otawara, Tochigi, Japan.
authors.forename: Kota
authors.initials: K
authors.lastname: Aoyagi
authors.affiliation: Toshiba Medical Systems Corporation, Otawara, Tochigi, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Yamagata
authors.affiliation: Toshiba Medical Systems Corporation, Otawara, Tochigi, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Sugihara
authors.affiliation: Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Japan.
authors.forename: Hisanobu
authors.initials: H
authors.lastname: Koyama
authors.affiliation: Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan; Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yoshikawa
authors.affiliation: Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Japan.
authors.forename: Kazuro
authors.initials: K
authors.lastname: Sugimura
mesh_terms: D000465:Algorithms; D016477:Artifacts; D003658:Decision Making, Computer-Assisted; D005374:Filtration / Q000379:methods / Q000706:statistics & numerical data; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods* / Q000706:statistics & numerical data; D021621:Imaging, Three-Dimensional / Q000379:methods / Q000706:statistics & numerical data; D055613:Multiple Pulmonary Nodules / Q000000981:diagnostic imaging; D019047:Phantoms, Imaging; D011446:Prospective Studies; D011829:Radiation Dosage; D013902:Radiography, Thoracic / Q000379:methods / Q000706:statistics & numerical data; D012984:Software; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000706:statistics & numerical data
keywords: CT; Computer-aided volumetry; Lung; Nodule; Radiation dose; Reconstruction algorithm