[The usefulness of fractal geometry for the diagnosis of small peripheral lung tumors].
OBJECTIVE
To assess the usefulness of fractal geometry in quantitatively evaluating the convergence of peripheral vessels on peripheral lung tumors in maximum intensity projection (MIP) images.


METHODS
We studied the MIP images of 34 pathologically proved small peripheral lung tumors (lung cancer in 21, hamartoma in 13) in 34 patients. To obtain MIP images, spiral CT (SOMATOM PLUS; Siemens) was performed during a single breath hold (24-second scan time, 2-mm section thickness, and 2 mm/sec table feed time, reconstructed at 1-mm increments). To evaluate the convergence of the peripheral vessels and bronchi towards the tumor, we fixed a region of interest (ROI) on the hilar side of the lung tumor, parallel to the chest wall, which consisted of 64 x 64 square pixels, in the images that divided at the center of the window width. We counted the overlapping pixels by the two-dimensional box-counting method and obtained fractal dimensional data on lung cancers and hamartomas.


RESULTS
There was a statistically significant difference in the fractal dimension (D) between lung cancers (D = 1.81 +/- 0.13) and hamartomas (D = 1.67 +/- 0.10) (P = 0.0067).


CONCLUSIONS
Fractal geometry could be useful in the diagnosis of small peripheral lung tumors.
Mihara
N
N
Department of Radiology, Osaka University Medical School.
Kuriyama
K
K
Kido
S
S
Kuroda
C
C
Johkoh
T
T
Naito
H
H
Nakamura
H
H
D003937:Diagnosis, Differential; D005260:Female; D017709:Fractals; D006222:Hamartoma / Q000000981:diagnostic imaging; D006801:Humans; D008171:Lung Diseases / Q000000981:diagnostic imaging; D008175:Lung Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed