Journal article
Maximizing quantitative accuracy of lung airway lumen and wall measures obtained from X-ray CT imaging
Journal of applied physiology (1985), Vol.95(3), pp.1063-1075
09/2003
DOI: 10.1152/japplphysiol.00962.2002
PMID: 12754180
Abstract
To objectively quantify airway geometry from three-dimensional computed tomographic (CT) images, an idealized (circular cross section) airway model is parameterized by airway luminal caliber, wall thickness, and tilt angle. Using a two-dimensional CT slice, an initial guess for the airway center, and the full-width-half-maximum principle, we form an estimate of inner and outer airway wall locations. We then fit ellipses to the inner and outer airway walls via a direct least squares fit and use the major and minor axes of the ellipses to estimate the tilt and in-plane rotation angles. Convolving the airway model, initialized with these estimates, with the three-dimensional scanner point-spread function forms the predicted image. The difference between predicted and actual images is minimized by refining the model parameter estimates via a multidimensional, unconstrained, nonlinear minimization routine. When optimization converges, airway model parameters estimate the airway inner and outer radii and tilt angle. Results using a Plexiglas phantom show that tilt angle is estimated to within ±4° and both inner and outer radii to within one-half pixel when a “standard” CT reconstruction kernel is used. By opening up the ability to measure airways that are not oriented perpendicular to the scanning plane, this method allows evaluation of a greater sampling of airways in a two-dimensional CT slice than previously possible. In addition, by combining the tilt-angle compensation with the deconvolution method, we provide significant improvement over the previous full-width-half-maximum method for assessing location of the luminal edge but not the outer edge of the airway wall.
Details
- Title: Subtitle
- Maximizing quantitative accuracy of lung airway lumen and wall measures obtained from X-ray CT imaging
- Creators
- Osama I Saba - University of IowaEric A Hoffman - University of IowaJoseph M Reinhardt - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Journal of applied physiology (1985), Vol.95(3), pp.1063-1075
- DOI
- 10.1152/japplphysiol.00962.2002
- PMID
- 12754180
- ISSN
- 8750-7587
- eISSN
- 1522-1601
- Language
- English
- Date published
- 09/2003
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering; Radiology; Internal Medicine
- Record Identifier
- 9984196997502771
Metrics
21 Record Views