title: The feasibility of Forward-projected model-based Iterative Reconstruction SoluTion (FIRST) for coronary 320-row computed tomography angiography: A pilot study.
abstract: BACKGROUND
  We aimed to assess and compare the influence of Forward projected model-based Iterative Reconstruction SoluTion (FIRST), a recently introduced full iterative reconstruction method, on radiation doses and image quality with that of Adaptive Iterative Dose Reduction (AIDR) 3D for 320-row cardiac computed tomography (CT).
  
  
  METHODS
  A total of 184 patients subjected to single-beat reconstruction cardiac CT were retrospectively included. The first 89 patients received standard radiation doses; their data were reconstructed using AIDR 3D, whereas the last 95 patients received in average 20% reduction in tube current; their data were reconstructed using FIRST. Subjective image quality (blooming, image sharpness, image noise, and overall subjective image quality) were graded using 3-, 5-, 4-, and 4-point scales (0-2, 1-5, 1-4, and 1-4), respectively; for all items, the highest score indicated excellent image quality. Image noise and signal-to-noise ratios at proximal segments were analyzed as objective measures of image quality.
  
  
  RESULTS
  FIRST reconstruction allowed 28% dose reduction compared with AIDR 3D (1.88 vs. 2.61 mSv, p = 0.012) and yielded better subjective image quality in terms of blooming, image sharpness, image noise, and overall image quality (1.10 vs. 1.01, p = 0.0007; 3.02 vs. 2.74, p < 0.0001; 3.61 vs. 3.17, p < 0.0001; and 3.30 vs. 2.98, p < 0.0001, respectively). Although no significant difference was observed in image noise, the signal-to-noise ratio was significantly higher with FIRST (18.4 vs. 16.6, p = 0.0066).
  
  
  CONCLUSIONS
  FIRST allowed 28% dose reduction while improving image quality.
authors.affiliation: Department of Radiology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. Electronic address: emaeda-tky@umin.ac.jp.
authors.forename: Eriko
authors.initials: E
authors.lastname: Maeda
authors.affiliation: Department of Radiology, New Tokyo Hospital, 1271 Wanagaya, Matsudo-city, Chiba, 270-2232, Japan.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Tomizawa
authors.affiliation: Department of Radiology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
authors.forename: Shigeaki
authors.initials: S
authors.lastname: Kanno
authors.affiliation: Department of Radiology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Yasaka
authors.affiliation: Department of Radiology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Kubo
authors.affiliation: Imaging Center, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Ino
authors.affiliation: Toshiba Medical Systems Corporation, Tokyo Metropolitan Regional Office, 1-6, Tsukuda 2-Chome, Chuo-ku, Tokyo, 104-0051, Japan.
authors.forename: Rumiko
authors.initials: R
authors.lastname: Torigoe
authors.affiliation: Department of Radiology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
authors.forename: Kuni
authors.initials: K
authors.lastname: Ohtomo
mesh_terms: D000368:Aged; D000072226:Computed Tomography Angiography / Q000379:methods*; D017023:Coronary Angiography / Q000379:methods*; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D010865:Pilot Projects; D011237:Predictive Value of Tests; D011829:Radiation Dosage; D000069079:Radiation Exposure; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012189:Retrospective Studies
keywords: 320-row CT; Coronary CT angiography; Image quality; Iterative reconstruction; Radiation dose