title: Model-based iterative reconstruction in pediatric chest CT: assessment of image quality in a prospective study of children with cystic fibrosis.
abstract: BACKGROUND
  The potential effects of ionizing radiation are of particular concern in children. The model-based iterative reconstruction VEO(TM) is a technique commercialized to improve image quality and reduce noise compared with the filtered back-projection (FBP) method.
  
  
  OBJECTIVE
  To evaluate the potential of VEO(TM) on diagnostic image quality and dose reduction in pediatric chest CT examinations.
  
  
  METHODS
  Twenty children (mean 11.4 years) with cystic fibrosis underwent either a standard CT or a moderately reduced-dose CT plus a minimum-dose CT performed at 100 kVp. Reduced-dose CT examinations consisted of two consecutive acquisitions: one moderately reduced-dose CT with increased noise index (NI = 70) and one minimum-dose CT at CTDIvol 0.14 mGy. Standard CTs were reconstructed using the FBP method while low-dose CTs were reconstructed using FBP and VEO. Two senior radiologists evaluated diagnostic image quality independently by scoring anatomical structures using a four-point scale (1 = excellent, 2 = clear, 3 = diminished, 4 = non-diagnostic). Standard deviation (SD) and signal-to-noise ratio (SNR) were also computed.
  
  
  RESULTS
  At moderately reduced doses, VEO images had significantly lower SD (P < 0.001) and higher SNR (P < 0.05) in comparison to filtered back-projection images. Further improvements were obtained at minimum-dose CT. The best diagnostic image quality was obtained with VEO at minimum-dose CT for the small structures (subpleural vessels and lung fissures) (P < 0.001). The potential for dose reduction was dependent on the diagnostic task because of the modification of the image texture produced by this reconstruction.
  
  
  CONCLUSIONS
  At minimum-dose CT, VEO enables important dose reduction depending on the clinical indication and makes visible certain small structures that were not perceptible with filtered back-projection.
authors.affiliation: Institute of Radiation Physics, Lausanne University Hospital, Grand-Pré 1 , 1007, Lausanne, Switzerland. frederic.mieville@gmail.com
authors.forename: Frédéric A
authors.initials: FA
authors.lastname: Miéville
authors.forename: Laureline
authors.initials: L
authors.lastname: Berteloot
authors.forename: Albane
authors.initials: A
authors.lastname: Grandjean
authors.forename: Paul
authors.initials: P
authors.lastname: Ayestaran
authors.forename: François
authors.initials: F
authors.lastname: Gudinchet
authors.forename: Sabine
authors.initials: S
authors.lastname: Schmidt
authors.forename: Francis
authors.initials: F
authors.lastname: Brunelle
authors.forename: François O
authors.initials: FO
authors.lastname: Bochud
authors.forename: Francis R
authors.initials: FR
authors.lastname: Verdun
mesh_terms: D000465:Algorithms; D002648:Child; D003198:Computer Simulation; D003550:Cystic Fibrosis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008954:Models, Biological; D011446:Prospective Studies; 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*