Figure 6

Quantitative measure of contrast estimated from the histogram of the micro-CT lung volumes. The histograms show the probability distribution of the voxel greyscale values (linear scale [HU]) from the concatenation of the segmented lung volumes available per condition. The axis legends are defined in the last graph and are the same for the three of them. A break in the y-axis is included from 16 to 28%. Renders of the micro-CT lung volumes from which the histograms have been computed are also shown The framing colour lines represent the legend of the graphs. Micro-CT scans of: (a) Lungs acquired in vivo (blue-dashed) and excised lungs without contrast agents (red); (b) Excised lungs with silver nitrate uptake acquired while embedded in ethanol (blue-dashed) and in paraffin (red); (c) Excised lungs with iodine uptake acquired while embedded in ethanol (blue-dashed) and in paraffin (red).