title: Attenuation-based automatic kilovoltage selection and sinogram-affirmed iterative reconstruction: effects on radiation exposure and image quality of portal-phase liver CT.
abstract: OBJECTIVE
  To compare the radiation dose and image quality between standard-dose CT and a low-dose CT obtained with the combined use of an attenuation-based automatic kilovoltage (kV) selection tool (CARE kV) and sinogram-affirmed iterative reconstruction (SAFIRE) for contrast-enhanced CT examination of the liver.
  
  
  METHODS
  We retrospectively reviewed 67 patients with chronic liver disease in whom both, standard-dose CT with 64-slice multidetector-row CT (MDCT) (protocol A), and low-dose CT with 128-slice MDCT using CARE kV and SAFIRE (protocol B) were performed. Images from protocol B during the portal phase were reconstructed using either filtered back projection or SAFIRE with 5 different iterative reconstruction (IR) strengths. We performed qualitative and quantitative analyses to select the appropriate IR strength. Reconstructed images were then qualitatively and quantitatively compared with protocol A images.
  
  
  RESULTS
  Qualitative and quantitative analysis of protocol B demonstrated that SAFIRE level 2 (S2) was most appropriate in our study. Qualitative and quantitative analysis comparing S2 images from protocol B with images from protocol A, showed overall good diagnostic confidence of S2 images despite a significant radiation dose reduction (47% dose reduction, p < 0.001).
  
  
  CONCLUSIONS
  Combined use of CARE kV and SAFIRE allowed significant reduction in radiation exposure while maintaining image quality in contrast-enhanced liver CT.
authors.affiliation: Department of Radiology, Chonbuk National University Medical School and Hospital, Biomedical Research Institute of Chonbuk National University Hospital, Jeonju 561-712, Korea.
authors.forename: Ji Soo
authors.initials: JS
authors.lastname: Song
authors.affiliation: Department of Radiology, Chonbuk National University Medical School and Hospital, Biomedical Research Institute of Chonbuk National University Hospital, Jeonju 561-712, Korea.
authors.forename: Eun Jung
authors.initials: EJ
authors.lastname: Choi
authors.affiliation: Department of Radiology, Chonbuk National University Medical School and Hospital, Biomedical Research Institute of Chonbuk National University Hospital, Jeonju 561-712, Korea.
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Kim
authors.affiliation: Department of Radiology, Chonbuk National University Medical School and Hospital, Biomedical Research Institute of Chonbuk National University Hospital, Jeonju 561-712, Korea.
authors.forename: Hyo Sung
authors.initials: HS
authors.lastname: Kwak
authors.affiliation: Department of Radiology, Chonbuk National University Medical School and Hospital, Biomedical Research Institute of Chonbuk National University Hospital, Jeonju 561-712, Korea.
authors.forename: Young Min
authors.initials: YM
authors.lastname: Han
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D002908:Chronic Disease; D003287:Contrast Media; D005260:Female; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography
chemical_list: D003287:Contrast Media
keywords: Computed tomography; Image quality; Iterative reconstruction; Radiation dose reduction; Tube potential