Tohoku J. Exp. Med., 2001, 194 (3)

Irregularity of Airway Branching in a Mouse Bronchial Tree: A 3-D Morphometric Study

KAZUYA ONUMA,^1,2 MASAHITO EBINA,¹ TOHRU TAKAHASHI^2,3 and TOSHIHIRO NUKIWA¹

¹Department of Respiratory Oncology and Molecular Medicine,
²Department of Pathology, Institute of Development, Aging and Cancer, Tohoku University, Sendai 980-8575, and
³Pathology Section, Ishinomaki Red Cross Hospital, Ishinomaki 986-8522

Limited information on the degree of irregularity of branching patterns of a bronchial tree may obscure the cause of heterogeneous distribution of the lesions in a variety of lung diseases. We reconstructed three dimensional (3-D) images from hilum to terminal bronchioles of a mouse lung, and defined the irregularity of airway branching by diameter-based morphometric analysis. The relative diameter ratios of a daughter to the parent branch (D1/D0) and those of a minor to major daughter branches (D1/D2) were calculated, and irregular dichotomies were found to be distributed in 48% of bifurcations. D1/D0 is well correlated with D1/D2, and is proved to indicate regular and irregular branching, as well as D1/D2. Irregular branches with D1/D0 smaller than 0.4 correspond to typical lateral branches, taking off from major bronchi. Our novel 3-D morphometric analysis showed the first portrayal of the 3-D structures of mouse bronchial airways, which provides a quantitative description of branching patterns leading to the correlation with distribution of lesions in the diseased lung.

Keywords —— morphometry; irregular airway branching; irregular branch

© 2001 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2001, 194, 157-164

Address for reprints: Masahito Ebina, M.D, Ph.D., Department of Respiratory Oncology and Molecular Medicine, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryomachi, Aoba-ku, Sendai 980-8575, Japan.

e-mail: ebinam@idac.tohoku.ac.jp