Acute myelopathy in a nontraumatic setting is a medical emergency requiring prompt diagnosis and intervention to prevent irreversible neurologic damage. Spinal MRI is the primary imaging modality used to assess suspected cord compression. Emergency department radiologists must be adept at differentiating compressive from noncompressive causes of myelopathy, as the management strategies differ significantly. This paper provides a concise overview of the MRI findings and differential diagnoses for nontraumatic spinal cord compression, focusing on a compartmental approach to localize lesions and refine diagnoses.
Anatomy of the Spinal Canal
The spinal canal is divided into three main compartments:
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Epidural Space: Located between the bony spinal canal and the dura mater, containing fat, spinal nerves, and vascular structures.
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Intradural Extramedullary Space: Situated between the arachnoid and pia mater, containing cerebrospinal fluid (CSF) and nerve roots.
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Intramedullary Space: Within the spinal cord itself.
Understanding these compartments is crucial for localizing lesions and determining the cause of myelopathy.