Page 36 - Advanced concepts in orbital wall fractures

Chapter 2
Statistical analysis
The results in this article were analysed in IBM SPSS Statistics (version 22.0; IBM Corp., Armonk, NY, USA). The volumes for the anterior boundary and manual segmentation were computed and descriptive statistics, mean difference, and standard deviation (SD) were calculated. The intraclass correlation coefficient (ICC) and 95 % confidence interval (CI) were measured to test the interobserver and intraobserver agreement for the volumetric measurements for both the anterior boundary as well as the manual segmentation (gold standard).
For the (semi-)automatic segmentation methods, the correlation between the gold standard and the computed volumes of the three separate methods was analysed using the mean difference and SD. For the SAA method, both interobserver and intraobserver agreement were measured using ICC and the 95 % CI of the bony orbital volumes. The average time in seconds and SD was also calculated for all three methods. Finally, Dice coefficients and distance maps were computed to compare the (semi-) automatic methods to the gold standard. For the distance maps, the mean difference on the border of the segmentation was compared in millimetres (mm). Both mean distance measure and the 95th percentile of the absolute distance measure were measured. Differences in the data were tested using a paired t test.
Figure 3 Screenshot of the automatic segmentation in iPlan 3.0.5. 34