title: Chest computed tomography using iterative reconstruction vs filtered back projection (Part 2): image quality of low-dose CT examinations in 80 patients.
abstract: OBJECTIVE
  To evaluate the image quality of an iterative reconstruction algorithm (IRIS) in low-dose chest CT in comparison with standard-dose filtered back projection (FBP) CT.
  
  
  METHODS
  Eighty consecutive patients referred for a follow-up chest CT examination of the chest, underwent a low-dose CT examination (Group 2) in similar technical conditions to those of the initial examination, (Group 1) except for the milliamperage selection and the replacement of regular FBP reconstruction by iterative reconstructions using three (Group 2a) and five iterations (Group 2b).
  
  
  RESULTS
  Despite a mean decrease of 35.5% in the dose-length-product, there was no statistically significant difference between Group 2a and Group 1 in the objective noise, signal-to-noise (SNR) and contrast-to-noise (CNR) ratios and distribution of the overall image quality scores. Compared to Group 1, objective image noise in Group 2b was significantly reduced with increased SNR and CNR and a trend towards improved image quality.
  
  
  CONCLUSIONS
  Iterative reconstructions using three iterations provide similar image quality compared with the conventionally used FBP reconstruction at 35% less dose, thus enabling dose reduction without loss of diagnostic information. According to our preliminary results, even higher dose reductions than 35% may be feasible by using more than three iterations.
authors.affiliation: Department of Thoracic Imaging, Hospital Calmette (EA 2694), University Lille Nord de France, F-59000, Lille, France.
authors.forename: François
authors.initials: F
authors.lastname: Pontana
authors.forename: Alain
authors.initials: A
authors.lastname: Duhamel
authors.forename: Julien
authors.initials: J
authors.lastname: Pagniez
authors.forename: Thomas
authors.initials: T
authors.lastname: Flohr
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Faivre
authors.forename: Anne-Lise
authors.initials: AL
authors.lastname: Hachulla
authors.forename: Jacques
authors.initials: J
authors.lastname: Remy
authors.forename: Martine
authors.initials: M
authors.lastname: Remy-Jardin
mesh_terms: D000465:Algorithms; D001822:Body Burden; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods*; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D013902:Radiography, Thoracic / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*