Computed tomography artifacts mimicking type II odontoid fractures: Report of two cases and review of the literature

Abstract

IntroductionComputed tomography (CT) has proved highly reliable for cervical spine trauma screening. Nevertheless, rare instances of equivocal imaging findings may lead to misdiagnosis and wrongful management. The role of CT artifacts in this setting has been overlooked. We report 2 cases in which CT-generated artifacts mimicked type II odontoid fractures and nearly misled clinical management. Case reports and literature reviewBoth patients suffered low energy falls and underwent cervical spine CT that disclosed an apparent dislocated type II odontoid fracture. Upon close inspection and review of the initial CT, the artifactual nature of the supposed fractures was exposed as motion artifact, avoiding unneeded surgery. In one of the cases, beam hardening artifact contributed to the false diagnosis. A review of the literature on false-positives in spinal trauma due to CT-generated artifacts was conducted, returning 14 reported cases, all of which generated by motion artifacts. To the best of our knowledge, this is the first report of beam hardening artifact contributing to such complication. ConclusionWith this report, type II odontoid fracture becomes the most common type of artifactual false-positive. The most frequent culprit is motion artifact, but beam hardening artifacts may also play a role. Anatomical factors such as proximity of C2 to the oropharynx and large range of motion of the occipito-atlanto-axial articulation complex might contribute to susceptibility for contamination by motion artifact. CT sagittal reconstructions more easily disclose odontoid fractures, but are also more prone to contamination by artifacts. In order to mitigate these errors, we stress the importance of clinical correlation and critical analysis of the axial images, noticing any blurring or doubling of the bony contours, accompanied by distortion of the adjacent soft tissues, particularly the pharyngeal air column. The CT localizer scout film can also be helpful when in doubt, as well as pursuing repeat scans or alternative imaging methods.