The relationships between LAA_n and LAA% in all lung fields.

<p>Solid and dashed line shows that the correlation is statistically significant and non-significant with the linear regression with spline models, respectively. A: In COPD, LAA_n increased once and thereafter decreased with increase of LAA%. In all intervals, LAA_n-LAA% relationships were statistically significant. B: In LAM, LAA_n increased with increase of LAA% from 0% to 11.5%, and thereafter LAA%- LAA_n relationship was not statistically significant. C: In BHDS, LAA_n increased with increase of LAA% from 0% to 20.8%, and thereafter LAA_n-LAA% relationship was not statistically significant. LAA%: percentage of lung field occupied by low attenuation areas; LAA_n: number of LAA cluster.</p

Results of the quantitative analysis of LAAs.

<p>Results of the quantitative analysis of LAAs.</p

The comparison of LAA_n among five LAA%-intervals.

<p>A: In COPD, interval III was the highest and intervals I and II were lower. B: In LAM, interval I was the lowest and there was no statistically significant difference among intervals II to V. C. In BHDS, intervals III and IV were higher than the other intervals. The line across the box indicates at the median. The bottom of the box is at 25th percentile, and the top is at 75th percentile value. The minimal and maximal values are shown with short horizontal lines ("whiskers").</p> <p>LAA%: percentage of lung field occupied by low attenuation areas; LAA_n: number of LAA cluster</p> <p>* p < 0.05; † p < 0.01.</p

The relationships between LAA_s and LAA% in all lung fields.

<p>A and B: In COPD and LAM, LAA_s increased exponentially with LAA%. C: In BHDS, LAA_s did not correlate with LAA%.</p> <p>BHDS: Birt-Hogg-Dubé syndrome; COPD: chronic obstructive pulmonary disease; LAA%: percentage of lung field occupied by low attenuation areas; LAA_s: mean size of LAA cluster; LAM: lymphangioleiomyomatosis.</p

Log–log plots of representative cumulative frequency distributions of the size of LAA clusters.

<p>In subjects with COPD (A), the five lung slices analyzed had LAA% values of 2.2 (●), 5.0 (〇), 15.2 (▲), 28.0 (Δ), and 42.1 (◆). In these five slices, <i>r</i>^<i>2</i> has a value of 0.96, 0.98, 0.99, 0.98, and 0.99, respectively. The corresponding D values are 0.97, 1.12, 0.98, 0.96, and 0.83, respectively. In subjects with LAM (B), the five lung slices analyzed had LAA% values of 2.0 (●), 6.7 (〇), 16.7 (▲), 26.9 (Δ), and 40.9 (◆). In these five slices, <i>r</i>^<i>2</i> has a value of 0.96, 0.93, 0.98, 0.95, and 0.89, respectively. The corresponding D values are 1.24, 1.34, 1.27, 1.11, and 1.11, respectively. In subjects with BHDS (C), the five lung slices analyzed had LAA% values of 2.0 (●), 5.7 (〇), 15.9 (▲), 24.6 (Δ), and 40.2 (◆). In these five slices, <i>r</i>^<i>2</i> has a value of 0.72, 0.84, 0.97, 0.99, and 1.0, respectively. The corresponding D values are 0.74, 0.78, 0.76, 1.30, and 0.97, respectively.</p> <p>BHDS: Birt-Hogg-Dubé syndrome; COPD: chronic obstructive pulmonary disease; LAA: low attenuation areas; LAA%: percentage of lung field occupied by low attenuation areas; LAM: lymphangioleiomyomatosis.</p

The comparison of LAA_s among five LAA%-intervals.

<p>A: In COPD, interval V was the highest and there was no statistically significant difference among intervals I to IV. B: In LAM, intervals I and II were lower and thereafter LAA_s increased step by step from intervals III to V. C: In BHDS, interval III was slightly higher than II, and there was no significant difference among the other intervals. The line across the box indicates the median. The bottom of the box is at 25th percentile, and the top is at 75th percentile value. The minimal and maximal values are shown with short horizontal lines ("whiskers").</p> <p>BHDS: Birt-Hogg-Dubé syndrome; COPD: chronic obstructive pulmonary disease; LAA%: percentage of lung field occupied by low attenuation areas; LAA_s: mean size of LAA cluster; LAM: lymphangioleiomyomatosis</p> <p>* p < 0.05, † p < 0.01.</p

The comparison of <i>r</i>² value among five LAA%-intervals.

<p>A: In COPD, interval I was lower than II, III and IV, and there was no statistically significant difference among intervals II to V. B: In LAM, interval IV was lower than intervals I and II. The <i>r</i>² value seemed to decrease step by step from intervals I to IV. C. In BHDS, there was no statistically significant difference among all intervals, however, <i>r</i>² value seemed to increase step by step from intervals I to V. The line across the box indicates at the median. The bottom of the box is at 25th percentile, and the top is at 75th percentile value. The minimal and maximal values are shown with short horizontal lines ("whiskers"). The horizontal line at <i>r</i>² = 0.90 in each panels A to C indicates the definition of fractal property. The figures above intervals in each panel indicate the percentage of CT images with fractal propety.</p> <p>BHDS: Birt-Hogg-Dubé syndrome; COPD: chronic obstructive pulmonary disease; LAA%: percentage of lung field occupied by low attenuation areas; LAM: lymphangioleiomyomatosis; <i>r</i>^<i>2</i>: values of coefficient of determination which indicate the goodness-of-fit of the power law</p> <p>* p < 0.05, † p < 0.01.</p

Analysis of LAA clusters on CT images.

<p>Original CT image of the lower lung field, and the same image as in original image but the individual cluster comprising contiguous LAA is shown in contrasting colors in a representative patient with COPD (A and B), LAM (C and D) and BHDS (E and F). The lung field was identified from the rest of the image, and the lumina of airways were excluded. In COPD, LAA also exists in seemingly normal region, and contiguous LAA regions (colored area) fuse and become large. On the other hand, in LAM and BHDS, LAAs are few in seemingly normal areas, and the contiguous LAA regions (colored area) seems to be independent.</p> <p>BHDS: Birt-Hogg-Dubé syndrome; COPD: chronic obstructive pulmonary disease; LAA: low attenuation areas; LAM: lymphangioleiomyomatosis.</p

Patients characteristics.

<p>Patients characteristics.</p