Comparison of the ossification centre images between standard computed tomography and micro-computed tomography.

Abstract

BACKGROUND\nBased on standard CT and micro-CT scan axis images, our study aims to analyze the incidence of variation of non-fusion ossification centre in the base of the odontoid and its anatomical structure characteristics, to compare ossification centre images and analyze the possible features of the ossification centre that can influence adult odontoid fractures.\n\n\nMATERIALS AND METHODS\nFifty cases were selected for standard cervical CT of the normal axis bone (second cervical) anatomy to calculate the incidence of variation of the non-fusion ossification centre in the base of the odontoid and the indexes of associated anatomical structure. In addition, five dry bone samples with the odontoid were chosen for Micro-CT to analyze the clear anatomic structure of the trabecular bone in the ossification centre.\n\n\nRESULTS\nIncidence of variation of non-fusion ossification centre in the base of the odontoid was 28%. In the non-ossification group, the mean sagittal diameter of the base of odontoid (SDBO, mm) was 7.64±1.29 mm, the mean transverse diameter of the base of odontoid (TDBO, mm) was 7.14±1.55 mm, and the SDBO:TDBO ratio was 1.1±0.22. In the ossification group, the mean SDBO was 7.7±1.15 mm, the mean TDBO was 7.38±1.32 mm, and the SDBO:TDBO ratio was 1.07±0.21. There was no significant difference in the associated indexes between the ossification and non-ossification groups (P>0.05). Micro-CT revealed the micro-structure of trabecular bone in the ossification centre and the close relationship between the trabecular bone and the odontoid. One existing non-ossification centre in the base of the odontoid was found in the five odontoid images. The trabecular bone indexes chosen in the target area of the ossification centre were weaker than those in other areas.\n\n\nCONCLUSIONS\nThe variation rate of the non-fusion ossification centre in the base of the odontoid is relatively high and may be an important factor in the etiology of type II & III odontoid fractures.