title: Model-based iterative reconstruction for detection of subtle hypoattenuation in early cerebral infarction: a phantom study.
abstract: OBJECTIVE
  Model-based iterative reconstruction (MBIR) was recently shown to enable dose reduction in computed tomography (CT). The detectability of low-contrast lesions was assessed on CT images reconstructed with MBIR compared with the conventional filtered back-projection (FBP) method.
  
  
  METHODS
  A phantom simulating brain gray matter containing small lesions mimicking early cerebral infarctions was scanned at tube currents of 50, 100, 200, and 400 mA. Images were reconstructed by use of both methods. Round regions were cropped from the reconstructed images, half with a lesion, the other half without. Eight radiologists reviewed the images and scored the certainty of lesion detection on a 5-point scale. Overall performance was analyzed by use of a receiver operating characteristic curve.
  
  
  RESULTS
  For the tube currents investigated, the analysis showed that the mean areas under the curves for the reviewers were 0.65, 0.70, 0.82, and 0.83 for FBP and 0.70, 0.76, 0.78, and 0.90 for MBIR. For each current, there was no significant difference between the areas under the curves for the different reconstruction methods (p = 0.32, 0.24, 0.49, and 0.17).
  
  
  CONCLUSIONS
  For the small, low-contrast lesions in the phantom model used in this study, no significant difference between detectability was observed for MBIR and FBP.
authors.affiliation: Department of Diagnostic and Interventional Radiology, Osaka University Graduate School of Medicine, 2-2, Yamadaoka, Suita, Osaka, 565-0871, Japan, m-nishizawa@radiol.med.osaka-u.ac.jp.
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Nishizawa
authors.forename: Hisashi
authors.initials: H
authors.lastname: Tanaka
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Yuuki
authors.initials: Y
authors.lastname: Kunitomi
authors.forename: Akio
authors.initials: A
authors.lastname: Tsukabe
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Tomiyama
mesh_terms: D002544:Cerebral Infarction / Q000503:physiopathology*; D008962:Models, Theoretical; D019047:Phantoms, Imaging; D012372:ROC Curve; D014057:Tomography, X-Ray Computed