Figure 3.

Relationship between alveolar fractal box dimension (D_B) and mean linear intercept (L_m). Each datum point is the mean D_B and L_m of one animal. (A) Porcine pancreatic elastase (PPE)-induced emphysema (N = 18). Estimated Spearman’s coefficient of correlation R = −0.94, P < 0.0001. (B) human neutrophil elastase (HNE)-induced emphysema (N = 14). Spearman’s coefficient, R = −0.834. P = 0.0001.

Notes: The slopes of the lines, −0.0028 and −0.0041, respectively, are significantly different when compared by an F-test (P < 0.0001). The negative correlation coefficients indicate that as airspace size L_m increases there is a corresponding decline in D_B, regardless of the type of elastase used to induce emphysema. The difference between the slopes of the lines indicates that HNE reduces D_B more for each unit of increase in airspace size L_m than does PPE.