[Imitation of an Anderson type II dens fracture by a motion artefact in computed tomography : Four case examples].

Computed tomography (CT) is the method of choice in the diagnosis and classification of odontoid fractures with a sensitivity of more than 99 % and a specificity almost equally as high. In this article we report on four cases where CT-generated motion artefacts exactly mimicked an Anderson type II fracture of the dens axis, initially leading to a wrong diagnosis. Although this seems to be a very rare event, these cases indicate that overlooked CT motion artefacts can lead to severe consequences and attention must be paid to the radiological signs outlined in this report.