Figure 1.

Representative LAV cluster size distributions for individual lungs in a control subject (circles) and a patient with COPD (triangle) fitted to a power law (solid lines). As illustrated here, the super cluster is identified for the patient with COPD as the LAV outlier (arrow) nearly three orders of magnitude larger than the remaining distribution, while a similar large cluster is not present in the distribution for the control patient. Inset: comparing distribution exponents across all patients, we found that values of D were significantly lower in patients with COPD compared with control subjects at baseline. COPD = chronic obstructive pulmonary disease; D = power law exponent; LAV = low-attenuation volume.