Spatial Distribution of the Peripheral Airways—Application of Fractal Geometry

Hiroko Kitaoka¹ and Harumi Itoh²

¹Department of Internal Medicine, Kitaoka Hospital, Kurayoshi, Japan
²Department of Radiology, Kyoto University School of Medicine, Kyoto, Japan

(Received March 4, 1991; Accepted April 6, 1991)

Keywords: Airways, Fractal, Three-Dimensional Reconstruction

Abstract. We examined the spatial distribution of peripheral airways applying fractal geometry. Part of a normal fixed lung specimen resected because of a small lung cancer was used. Reconstructed three-dimensional images of peripheral airways from a sub-sub segmental bronchus to its terminal bronchioli were processed using a personal computer from serial thin-sliced (0.5-mm) lung specimens. These data were used to examine whether spatial distribution of the peripheral airways has selfsimilarity. A three-dimensional box-counting method was applied using the computer system and fractal dimensions were measured at three different areas. The results indicated that the spatial distribution of the airways is approximately self-similar with fractal dimensions 1.7 in all areas. It was interpreted that spatial structural style of airways could be represented quantitatively by fractal geometry.