1. A, CT myelogram demonstrates the scalpel sign with the characteristic focal dorsal indentation of the upper thoracic spinal cord.
A, CT myelogram demonstrates the scalpel sign with the characteristic focal dorsal indentation of the upper thoracic spinal cord. An insert of a scalpel shows how the dorsal indentation relates to the pointed edge of the blade. B, Corresponding axial image above the level of dorsal indentation (level of the arrow in A). C, Corresponding axial image at the level of dorsal indentation (level of the arrowhead in A).
M.A. Reardon et al. AJNR Am J Neuroradiol 2013;34:
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