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Normal Variants and Mimics in Spinal Trauma Every Radiologist Should Know 2013

Category General Spine Kory Byrns
Allison Rubin
Steven Lev
Purpose Educational objectives: 1. Review non-traumatic findings and normal variants on computed tomography of the cervical, thoracic, lumbar, and sacral spine that may mimic actual trauma 2. Provide tools and examples that the radiologist needs to confidently differentiate these entities 3. Avoid misdiagnosis in the setting of trauma and thus prevent missed pathology as well as unnecessary additional workup Materials & Methods In the setting of acute trauma involving the spine, the radiologist on call is under tremendous pressure to accurately and expeditiously sort through the vast amount of information multidetector computed tomography (MDCT) provides, and to extract the pertinent abnormalities. Wary of passing over a potentially life-threatening finding, the radiologist may overcompensate and characterize normal or otherwise benign findings as traumatic lesions. We aim to provide examples of commonly encountered mimics of trauma from our Level 1 trauma center during the past five years. We organize our discussion according to both anatomical location and the nature of the misleading finding. Benign calcifications are a troublesome impostor that the experienced radiologist must master, including limbus fragments of cervical vertebrae that mimic teardrop fracture fragments. The impressive resolution of MDCT reveals many fine anatomical structures that can be similarly confounding if they are not expected. These include normal bony lucencies, such as the basivertebral plexus and pediatric csynostoses. Developmental non-fusion of ossification centers is an abnormal but otherwise benign osseous defect that may bear a striking resemblance to unstable injuries such as Jefferson or type II dens fractures. Technical considerations are also reviewed in depth; for example, poor positioning or artifacts may not be readily recognized or can be easily misinterpreted, and the radiologist must know when it is appropriate to recommend repeating and/or altering the study to clarify the results. Rotation of the cervical spine, even by a slight amount, for example, may appear on CT as a profound subluxation. Streak, mottle, volume averaging, and motion artifacts are unfortunate realities of scanning patients in an emergent and often less than ideal setting, and must not be mistaken for devastating injuries. Results   Conclusion Routine MDCT evaluation of spinal trauma has vastly improved detection of lesions, but the savvy radiologist must know how to filter out frequently encountered mimics of pathology. By studying and retaining the examples and concepts discussed here, misdiagnoses can be avoided. References