title: Qualitative and quantitative assessment of smoking-related lung disease: effect of iterative reconstruction on low-dose computed tomographic examinations.
abstract: OBJECTIVE
  The purpose of this research is to examine the role that differing levels of adaptive statistical iterative reconstruction (ASIR) have on the qualitative and quantitative assessment of smoking-related lung disease.
  
  
  METHODS
  Institutional board review approval was obtained. A total of 52 patients undergoing clinically indicated low-dose computed tomographic (CT) examinations of the chest (100 kVp, 65 mAs, mean radiation dose 1.0±0.12 mSv), with reconstruction of data with different levels of blended ASIR (0%, 40%, and 100%), were consented. Qualitative assessment of CT data sets was performed by 2 trained thoracic radiologists blinded to clinical history, spirometry, and quantitative data for the presence of emphysema (%/lung zone) and the degree of respiratory bronchiolitis. Quantitative analysis was performed (Apollo Image analysis, VIDA Diagnostics) to assess emphysema and airway measures of chronic obstructive pulmonary disease.
  
  
  RESULTS
  The application of ASIR results in alterations in both qualitative and quantitative assessment of smoking-related lung disease. As levels of ASIR increased, both readers scored more respiratory bronchiolitis (P<0.05). At increased levels of ASIR (ie, 100% vs. 0%), the amount of emphysema measured (% below -950 HU) decreased, the number of airways measured diminished, and the airway thickness (Pi10mm) increased (P<0.001).
  
  
  CONCLUSIONS
  The use of ASIR alters both the qualitative and quantitative assessment of smoking-related lung disease. Although a powerful tool to allow dose reduction, caution must be exercised when iterative reconstruction techniques are utilized when evaluating CT examinations for findings of chronic obstructive pulmonary disease.
authors.affiliation: Departments of *Radiology ∥Radiology and Cardiology ¶Medicine, Division of Respirology, James Hogg Research Center & The Institute of Heart and Lung Health, University of British Columbia, St. Paul's Hospital †James Hogg Research Center & The Institute of Heart and Lung Health Departments of #Radiology and Cardiology **Radiology, James Hogg Research Center & The Institute of Heart and Lung Health, University of British Columbia, Vancouver General Hospital, Vancouver, BC §Department of Radiology McGill University Health Centre, Montreal, QC, Canada ‡Department of Diagnostic Imaging, King Fahd Military Medical Complex, Dhahran, Kingdom of Saudi Arabia.
authors.forename: Cameron J
authors.initials: CJ
authors.lastname: Hague
authors.forename: Natasha
authors.initials: N
authors.lastname: Krowchuk
authors.forename: Donya
authors.initials: D
authors.lastname: Alhassan
authors.forename: Kevin
authors.initials: K
authors.lastname: Ho
authors.forename: Jonathon
authors.initials: J
authors.lastname: Leipsic
authors.forename: Don D
authors.initials: DD
authors.lastname: Sin
authors.forename: John R
authors.initials: JR
authors.lastname: Mayo
authors.forename: Harvey O
authors.initials: HO
authors.lastname: Coxson
mesh_terms: D001988:Bronchiolitis / Q000000981:diagnostic imaging; D015984:Causality; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging* / Q000209:etiology*; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012907:Smoking / Q000009:adverse effects*; D014057:Tomography, X-Ray Computed / Q000379:methods*