Explore the correctness of three-dimensional anatomical metric studies of bone objects obtained by cone beam computed tomography Morita Veraviewepocs 3D
The aim of this study was to determine the correctness of the use of cone-beam CT Morita Veraviewepocs 3D for accurate metric measurement of cranial structures as well as defining the difference between traditional measurements directly anatomical object and its virtual digital counterpart.
Materials and methods. This study compared the vertical, horizontal, transversal characteristics obtained by the conventional measurements of standard marker points on the dry skull using a attorney caliper with the data obtained in the software shell i-Dixel One Volume Viewer (Ver.1.5.0) J Morita Mfg Corp in analysis of i-Dixel database obtained on cone-beam CT Morita Veraviewepocs 3D. 23 identical measurements were carried out directly on the anatomical object caliper and a three-dimensional reconstructed analog programmatically. Statistical analysis was performed using the statistical software package Statistica 6.1.
Results. For qualitative characteristics of the measurement and detection of possible system errors were analyzed the presence of significant differences between the measurements of various researchers. For this purpose has been used a non-parametric Wilcoxon test W, which is based on ranks and used for comparing the value measured in two different conditions on the same subjects sample. The results of the statistical analysis for measuring conducted by caliper in the shell program i-Dixel One Volume Viewer confirmed the null hypothesis, ie there are no significant differences between the measurements conducted by different researchers.
To understand the nature of the relationship between the two groups of measurements is convenient to use Spearman correlation coefficient as a measure of the linear relationship between random variables. Spearman correlation is rank that is to assess the strength of communication are used not numerical value but the corresponding grades. The coefficient is invariant in relation to any monotonic transformation of the measurement scale. The high value of the Spearman correlation coefficient - 0.99 suggests a close linear relationship, however, to assess the consistency that is not enough. Table 3 shows the detailed description of consistency two types of measurements between each other the method of Bland-Altman. Its data allow to make a number of conclusions. Firstly, the mean difference between the measurements is only 0.28, which indicates the absence of systematic differences. Secondly, the standard deviation of the difference was 0.51, which is low compared to the values themselves. Third, there is no dependence of difference measurement from the value indicator. Thus, measurements obtained by both methods are in good agreement with each other.
Conclusions. The findings confirm a fairly accurate reproduction of metric virtual three-dimensional digital model of the cranial bone structure, obtained by the cone-beam computed tomography Morita Veraviewepocs 3D, and software shell i-Dixel One Volume Viewer (Ver.1.5.0) J Morita Mfg Corp.