Skip to main content
Fig. 3 | BMC Pulmonary Medicine

Fig. 3

From: Fractal analysis of low attenuation clusters on computed tomography in chronic obstructive pulmonary disease

Fig. 3

Associations of the fractal dimensions with a proxy for inspiration level at CT scan, LAA%, and diffusion capacity. a A proxy for inspiration indicates the degree of the inspiration level during a CT scan that was obtained as a ratio of CT-derived total lung volume (CT-TLV) to physiologically-measured total lung capacity (TLC). This proxy correlated with D based on a fixed threshold of − 950 HU (D950) but not with D based on a threshold of the 15th, 25th, and 35th percentiles of a CT density histogram. b An increase in percent low attenuation area (LAA%) and (c) a decrease in the diffusion capacity of carbon monoxide (%DLCO) were correlated with reductions in D950, D’25, and D’35, but not D’15. Blue dots indicate the 144 cases with better-quality scans defined as those with the proxies for inspiration > 0.8 and < 1.2. Rall and Rsub indicate coefficient correlations for the analysis of all scans (n = 170) and the subanalysis of the better-quality scans (n = 144), respectively. * p < 0.05 and ** p < 0.01

Back to article page