title: Low-dose computed tomography of the chest using iterative reconstruction versus filtered back projection:  comparison of image quality.
abstract: OBJECTIVE
  The purpose of this study was to compare image quality of iterative reconstruction (IR) to filtered back projection (FBP) in low-dose computed tomography of the chest.
  
  
  METHODS
  Forty-three consecutive patients were retrospectively enrolled. Eight series of images were reconstructed using FBP and 7 levels of IR in each subject. Image noise, signal-to-noise ratio (SNR), and SNR improvement were measured. Two radiologists evaluated subjective artifact, image artificiality, and subjective overall image quality with 4- or 5-point scales.
  
  
  RESULTS
  Iterative reconstruction showed significantly lower image noise (135.5 ± 36.6 vs 219.9 ± 40.9) and higher SNR (0.36 ± 0.12 vs 0.21 ± 0.05) than FBP (P < 0.001). Signal-to-noise ratio improvement was 72.4% ± 44.9%. Subjective artifact of FBP was significantly higher than IR images (P < 0.001). Image artificiality of IR was significantly higher than that of FBP (P < 0.001). Overall, subjective image quality was poor in FBP and acceptable or good in IR.
  
  
  CONCLUSIONS
  With the use of IR, low-dose computed tomography of the chest would achieve less image noise and better image quality compared to the FBP.
authors.affiliation: Department of Radiology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Korea.
authors.forename: Youkyung
authors.initials: Y
authors.lastname: Lee
authors.forename: Kwang Nam
authors.initials: KN
authors.lastname: Jin
authors.forename: Nyoung Keun
authors.initials: NK
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D016477:Artifacts; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D013902:Radiography, Thoracic / Q000379:methods*; D012189:Retrospective Studies; D059629:Signal-To-Noise Ratio; D014057:Tomography, X-Ray Computed / Q000379:methods*