Transverse Myelitis¶
Definition¶
Transverse myelitis (TM) is an inflammatory disorder of the spinal cord characterized by acute or subacute onset of motor, sensory, and autonomic dysfunction. It can occur as an isolated idiopathic condition, as part of a systemic autoimmune disease (SLE, sarcoidosis, Sjögren syndrome), or as a manifestation of a demyelinating disease (multiple sclerosis, neuromyelitis optica spectrum disorder).
Imaging Findings¶
MRI¶
- T2-weighted — Hyperintense intramedullary signal spanning variable lengths of the cord, often >3 segments
- Cord expansion — Mild swelling of the cord at the affected segment during the acute phase
- Enhancement — Variable; may show patchy, nodular, or ring enhancement on post-contrast images during the acute phase
- Location — Can affect any level; thoracic cord is most common for idiopathic TM
Distinguishing Patterns by Etiology¶
| Feature | Idiopathic TM | MS | NMOSD (Devic) |
|---|---|---|---|
| Length | Variable (often >3 segments) | Short segment (<2 vertebral bodies) | Long segment (≥3 vertebral bodies) |
| Cross-section | Central, >2/3 cord area | Peripheral, <50% cord area | Central, >2/3 cord area |
| Cord swelling | Mild | Minimal | Moderate to marked |
| Enhancement | Variable | Incomplete ring or nodular | Ring or patchy |
| Brain lesions | Absent | Periventricular white matter lesions | Absent or non-MS pattern |
| Optic nerve | Normal | May be involved | Frequently involved (optic neuritis) |
Clinical Pearl
The longitudinally extensive transverse myelitis (LETM) pattern — T2 hyperintensity spanning ≥3 vertebral segments with central cord involvement — is highly suggestive of neuromyelitis optica spectrum disorder (NMOSD) and should prompt testing for aquaporin-4 (AQP4) antibodies. This distinction from MS is critical because NMOSD and MS require different treatments, and some MS therapies can worsen NMOSD.
Key Points¶
- Transverse myelitis demonstrates intramedullary spinal cord T2 hyperintensity with variable cord expansion and enhancement
- Short-segment, peripheral lesions suggest MS; long-segment, central lesions suggest NMOSD
- Test for AQP4 antibodies when longitudinally extensive myelitis is present
- Thoracic cord is most commonly affected in idiopathic TM
- Brain MRI should be obtained to evaluate for MS or NMOSD
References¶
- Transverse Myelitis Consortium Working Group. Proposed diagnostic criteria and nosology of acute transverse myelitis. Neurology. 2002;59(4):499-505. https://pubmed.ncbi.nlm.nih.gov/12236201/
- Wingerchuk DM, Banwell B, Bennett JL, et al. International consensus diagnostic criteria for neuromyelitis optica spectrum disorders. Neurology. 2015;85(2):177-189. https://pubmed.ncbi.nlm.nih.gov/26092914/
- Simone CG, Emmady PD. Transverse Myelitis. In: StatPearls. Treasure Island (FL): StatPearls Publishing; updated 2022 Nov 15. https://www.ncbi.nlm.nih.gov/books/NBK559302/
- Lee MJ, Aronberg R, Manganaro MS, Ibrahim M, Parmar HA. Diagnostic Approach to Intrinsic Abnormality of Spinal Cord Signal Intensity. RadioGraphics. 2019;39(6):1824-1839. https://pubmed.ncbi.nlm.nih.gov/31589577/
- Agarwal V, Shah LM, Parsons MS, et al. ACR Appropriateness Criteria® Myelopathy: 2021 Update. J Am Coll Radiol. 2021;18(5S):S73-S82. https://pubmed.ncbi.nlm.nih.gov/33958120/
- Transverse myelitis. Radiopaedia.org. https://radiopaedia.org/articles/transverse-myelitis