Time course of new densities. (A) New densities (y axis) as a function of time (x axis) in individual piglets. We used all the computed tomography scans taken during the whole experiment until densities were distinguishable (time 3). Healthy pigs were represented by white dots and piglets with baseline abnormal densities by black dots. (B) Average number of new densities ±SD (y axis) as function of time (x axis) using 3-h intervals. We used only the computed tomography scan taken at 3-h intervals; regression was performed on average data and is purely descriptive. As behavior of individual piglets was different, we computed the time constant for seven piglets (in two piglets, the increase in new densities was linear, and in three piglets, there were not enough data points to fit a curve), and the median time constant was 3.1 h (interquartile range, 1.5 to 3.3).