Accurate measurement of intrathoracic airways

IEEE Trans Med Imaging. 1997 Dec;16(6):820-7. doi: 10.1109/42.650878.


Airway geometry measurements can provide information regarding pulmonary physiology and pathophysiology. There has been considerable interest in measuring intrathoracic airways in two-dimensional (2-D) slices from volumetric X-ray computed tomography (CT). Such measurements can be used to evaluate and track the progression of diseases affecting the airways. A popular airway measurement method uses the "half-max" criteria, in which the gray level at the airway wall is estimated to be halfway between the minimum and maximum gray levels along a ray crossing the edge. However, because the scanning process introduces blurring, the half-max approach may not be applicable across all airway sizes. We propose a new measurement method based on a model of the scanning process. In our approach, we examine the gray-level profile of a ray crossing the airway wall and use a maximum-likelihood method to estimate the airway inner and outer radius. Using CT scans of a physical phantom, we present results showing that the new approach is more accurate than the half-max method at estimating wall location for thin-walled airways.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Bronchi / anatomy & histology
  • Bronchography*
  • Humans
  • Image Processing, Computer-Assisted*
  • Phantoms, Imaging
  • Tomography, X-Ray Computed* / methods