Three-dimensional visualization and morphometry of small airways from microfocal X-ray computed tomography

Toshihiro Sera*, Hideki Fujioka, Hideo Yokota, Akitake Makinouchi, Ryutaro Himeno, Robert C. Schroter, Kazuo Tanishita

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

47 Citations (Scopus)


Physiological morphometry is a critical factor in the flow dynamics in small airways. In this study, we visualized and analyzed the three-dimensional structure of the small airways without dehydration and fixation. We developed a two-step method to visualize small airways in detail by staining the lung tissue with a radiopaque solution and then visualizing the tissue with a cone-beam microfocal X-ray computed tomographic (CT) system. To verify the applicability of this staining and CT imaging (SCT) method, we used the method to visualize small airways in excised rat lungs. By using the SCT method to obtain continuous CT images, three-dimensional branching and merging bronchi ranging from 500 to 150μm (the airway generation=8-16) were successfully reconstructed. The morphometry of the small airways (diameter, length, branching angle and gravity angle between the gravity direction and airway vector) was analyzed using the three-dimensional thinning algorithm. The diameter and length exponentially decreased with the airway generation. The asymmetry of the bifurcation decreased with generation and one branching angle decided the other pair branching angle. The SCT method is the first reported method that yields faithful high-resolution images of soft tissue geometry without fixation and the three-dimensional morphometry of small airways is useful for studying the biomechanical dynamics in small airways.

Original languageEnglish
Pages (from-to)1587-1594
Number of pages8
JournalJournal of Biomechanics
Issue number11
Publication statusPublished - 2003 Nov 1
Externally publishedYes


  • Cone-beam microfocal X-ray CT
  • Sodium diatrizoate
  • Soft tissue
  • Three-dimensional thinning algorithm

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine


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