Seed points are placed manually in the aerated lung (B). Segmentation of the aerated lung is performed by applying a region growing algorithm (C). The entire aerated parts of the lung are segmented. No spread of segmentation volume into adjacent structures

occurred. Figure 2 Segmentation of aerated lung volume as a surrogate to assess the multifocal tumor spread in SPC-raf transgenic animal. Micro-CT showing the distinctive diffuse bilateral tumour growth (A). Seed points are placed manually in the aerated lung (B). Segmentation of the aerated lung is performed applying a region growing algorithm (C). Note that the lung areas consolidated by tumour are correctly excluded from the segmentation volume, no Nutlin-3 in vivo overspilling of segmentation volume Seliciclib research buy into adjacent anatomical structures. Statistical analysis Statistical analysis was performed using IBM SPSS Statistics 19 (IBM Corp., Armonk, NY, USA). A repeated measurement analysis was performed. Due to the limited number of animals the number of

time points analysed had to be reduced. Analysis was performed for time points 2, 4, 6, 7-13 months. Due to a limited number of measurements one animal had to be excluded from the statistical analysis (see above, the animal had to Selleck RG-7388 be euthanized on day 146). Furthermore a linear regression analysis was performed and the correlation coefficient was calculated. P < 0.05 was considered as statistical significant. Results Micro-CT and Post-Processing No adverse events occurred due to the imaging procedures or anesthesia. Image quality was good in most cases and acceptable in

all cases. In this follow-up study progressive tumour burden could be seen in SPC-raf transgenic mice, while no obvious changes were noted in the control group (Figure 3 and 4). Visual correlation of histology and micro-CT at the corresponding time-point showed good accordance. Figure 3 Time-course of tumour progressing in micro-CT of a single SPC-raf transgenic animal (No.2; months 2-13). Axial slice orientation in corresponding Immune system positions. The multifocal tumour progression is clearly depicted. Histology at 13 months shows distinctive tumour burden in corresponding areas. Figure 4 Estimated marginal means of the segmentation volumes of the aerated parts of the lungs as an inverse surrogate parameter for tumour burden in SPC-raf transgenic (blue) and control animals (green) against time. Initial increase is assumed to result from normal growth of the animals. Note the distinct separation of the curves from 5 months on. Statistical analysis of later timepoints showed significant differences (p = 0.043). The region growing segmentation using the described post-processing algorithm could be performed in all cases.