306 Rank sum tests were performed to test whether the automatic quantification is able to distinguish complete and partial fissures. In case three categories were scored by the visual read (complete, partial, absent), the Kruskal- Wallis test was applied. To test the sensitivity of the automatic quantification, Receiver Operating Characteristic curves (ROC) were constructed for the automatic quantifi- cation compared with each visual read, defining a complete fissure as a positive test. The level of statistical significance was set to 0.05. This was implemented using Stata V.10.0 (College Station, TX, USA). Results Figure 2 shows descriptive statistics for both the automatic quantification and the visual consensus scores. It can be appreciated that the left major fissure is most often scored as complete by the visual consensus as well as by the Eur Radiol (2012) 22:302–309 automatic method. The automatic computation was suc- cessfully run on all CT studies. Figure 3 shows examples of the output of the automatic fissural completeness method on coronal slices of 4 CT studies. Figure 4 shows boxplots for the completeness of each fissure compared with the consensus read, divided into the different categories of the visual reads. For all three fissures, compared with each visual read, the automatic quantifications are significantly different for the complete fissures than for the partial fissures (all p values <0.001). In addition, for the right minor fissure, the automatic scores for the absent fissures are significantly different from those of the partial and complete fissures (p < 0.001). The ROC curves evaluating the automatic fissural com- pleteness quantification to the individual reads and the consensus read are shown in Fig. 5, along with the corresponding areas under the ROC curve (AUC). The AUCs from the consensus read were 0.88, 0.91 and 0.83 for the right major, right minor and left major fissures respectively. Fig. 4 a: Box-plots showing the quantitative fissural completeness score for each visually scored category for the right major fissure. b: Box-plots showing the quantitative fissural completeness score for each visually scored category for the right minor fissure. c: Box-plots showing the quantitative fissural completeness score for each visually scored category for the left major fissure