title: Diagnostic performance of reduced-dose CT with a hybrid iterative reconstruction algorithm for the detection of hypervascular liver lesions: a phantom study.
abstract: OBJECTIVE
  To investigate the diagnostic performance of reduced-dose CT with a hybrid iterative reconstruction (IR) algorithm for the detection of hypervascular liver lesions.
  
  
  METHODS
  Thirty liver phantoms with or without simulated hypervascular lesions were scanned with a 320-slice CT scanner with control-dose (40 mAs) and reduced-dose (30 and 20 mAs) settings. Control-dose images were reconstructed with filtered back projection (FBP), and reduced-dose images were reconstructed with FBP and a hybrid IR algorithm. Objective image noise and the lesion to liver contrast-to-noise ratio (CNR) were evaluated quantitatively. Images were interpreted independently by 2 blinded radiologists, and jackknife alternative free-response receiver-operating characteristic (JAFROC) analysis was performed.
  
  
  RESULTS
  Hybrid IR images with reduced-dose settings (both 30 and 20 mAs) yielded significantly lower objective image noise and higher CNR than control-dose FBP images (P < .05). However, hybrid IR images with reduced-dose settings had lower JAFROC1 figure of merit than control-dose FBP images, although only the difference between 20 mAs images and control-dose FBP images was significant for both readers (P < .01).
  
  
  CONCLUSIONS
  An aggressive reduction of the radiation dose would impair the detectability of hypervascular liver lesions, although objective image noise and CNR would be preserved by a hybrid IR algorithm.
  
  
  CONCLUSIONS
  • A half-dose scan with a hybrid iterative reconstruction preserves objective image quality. • A hybrid iterative reconstruction algorithm does not improve diagnostic performance. • An aggressive dose reduction would impair the detectability of low-contrast lesions.
authors.affiliation: Department of Radiology, Osaka Medical College, 2-7, Daigaku-machi, Takatsuki, Osaka, Japan, 569-8686. rad117@osaka-med.ac.jp.
authors.forename: Atsushi
authors.identifier: http://orcid.org/0000-0001-8540-1855
authors.initials: A
authors.lastname: Nakamoto
authors.affiliation: Department of Radiology, Osaka Medical College, 2-7, Daigaku-machi, Takatsuki, Osaka, Japan, 569-8686.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Tanaka
authors.affiliation: Department of Radiology, Osaka Medical College, 2-7, Daigaku-machi, Takatsuki, Osaka, Japan, 569-8686.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Juri
authors.affiliation: Department of Radiology, Osaka Medical College, 2-7, Daigaku-machi, Takatsuki, Osaka, Japan, 569-8686.
authors.forename: Go
authors.initials: G
authors.lastname: Nakai
authors.affiliation: Central Radiology Department, Osaka Medical College Hospital, Takatsuki, Osaka, Japan.
authors.forename: Shushi
authors.initials: S
authors.lastname: Yoshikawa
authors.affiliation: Department of Radiology, Osaka Medical College, 2-7, Daigaku-machi, Takatsuki, Osaka, Japan, 569-8686.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Narumi
mesh_terms: D000465:Algorithms; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging*; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: Diagnostic imaging; Image reconstruction; Liver; Multidetector computed tomography; Radiation dosage