Myelopathy + a diffuse T2-hyperintense region of cord

Playing the odds 
- most likely is compression - from disc, tumor (met), trauma
- in the absence of that, most likely is demyelinating, esp MS - esp if its short segments, and there are multiple disparate lesions in random-seeming locations.
- long-segment disease - think NMO (esp if there are optic sx) or transverse myelitis (not a dz, a description of a constellation of symptoms that are caused by other things)

Transverse Myelitis etiology:
- Viral - HSV, VZV, CMV, EBV, enteroviruses (echo, coxsackie, polio), HIV, influenza, rabies, HTLV (human T cell lymphoma virus),
- Bacterial - TB, Lyme
- Autoimmune - Sarcoid, Sjogrens, Lupus
- Post vaccine - rabies, cowpox
- MS
- Paraneoplastic
- Vascular - DAF, AVM, clot of spinal aa, heroin vasculitis

Intramedullary Spine tumors
- In adults, ependymoma > astrocytoma
- In kids, astrocytoma > ependymoma
- Astrocytomas tend to look more like diffuse, +/- enhancing regions of cord with a good bit of swelling, and they tend to be associated with slowly progressive symptoms - in the context of an enhancing lesion with rapidly progressive sx and optic symptoms - think NMO, rather than astrocytoma.
- Ependymomas and Hemangioblastomas tend to look more like actual tumors
- Ependymomas often have a cap of hemosiderin at the top and bottom - from prior bleeds - and may have a cystic component

Super helpful diagrams from radiologyassistant.nl:

MS 

- Active lesions in the spine, tend to NOT enhance - in the brain, can enhance 

- If you suspect spine MS (i.e. multiple non-enhancing lesions that are small, and separate in time and space) - then get a brain MRI - if you see characteristic lesions in the corpus callosum/periventricular/pons/subcortical area, increases likelihood of MS

- 1/3 will have spinal symptoms, 95% will have spinal lesions (path dx) - irrespective of symptoms 

- 1/3 of people will have spinal MS ONLY and no brain MS