RESEARCH Open Access Measurement of three-dimensional morphological

Background: Although computed tomography (CT) with three-dimensional (3D) rendering of the calcaneus is used for diagnostic evaluation of disorders, morphological measurements for the calcaneus are mostly based on a two-dimensional plane. The purposes of this study were to design a method for 3D morphological measurements of the normal calcaneus based on CT post-processing techniques, to measure morphological parameters in the male and female groups and describe gender differences of the parameters, and to investigate the reliability of such measurements. Methods: One hundred and seventy-nine patients (83 men and 96 women) with a mean age of 40.6 (range, 21 to 59) years who underwent CT scans for their feet were reviewed retrospectively. The 3D structure of a normal calcaneus after shaded surface display reconstruction was extracted by interactive and automatic segmentation. Morphological measurements were achieved by means of a 3D measurement method based on CT image post-processing. Lengths and heights of the main parts of the calcaneus, Gissane’s angle, Böhler’s angle and the area of articular facet were worked out in 3D space. Gender-related size differences of parameters were compared using analysis of covariance (ANCOVA), adjusting for body height. Intra-observer and inter-observer reliabilities were assessed using intraclass correlation coefficients (ICCs) and the root mean square standard deviation (RMS-SD) for precision study