Subarachnoid Space Narrowing

Bryson Borg, MD

DIFFERENTIAL DIAGNOSIS

Common

Less Common

ESSENTIAL INFORMATION

Helpful Clues for Common Diagnoses

Stenosis, Acquired Spinal
- Multifactorial process involving disc herniation and degenerative hypertrophy of the posterior elements
Stenosis, Congenital Spinal
- Developmentally narrow canal; short, thick pedicles
- Frequency: Lumbar > cervical > thoracic
Hematoma, Epidural-Subdural
- May be spontaneous or associated with trauma or instrumentation
- Signal varies with the age of the hemorrhage
- Mild or no enhancement
Abscess, Epidural
- May be associated with disc space infection or instrumentation/inoculation
- Marked peripheral enhancement typical
Meningioma
- Dural-based, circumscribed, enhancing mass
Multiple Sclerosis, Spinal Cord (Acute)
- Cord expansion uncommon, indicates an acute lesion; resolves in 6-8 weeks
- Hyperintense on T2WI, variable enhancement
- Image brain to check for supratentorial lesion(s)
Ependymoma, Cellular, Spinal Cord
- Circumscribed, enhancing intramedullary mass
- Necrosis and hemorrhage possible
Astrocytoma, Spinal Cord
- Fusiform enlargement, infiltrative margins; no or variable enhancement
- Imaging cannot reliably differentiate from ependymoma
- Appearance can be simulated by acute MS, ADEM, neuromyelitis optica, myelitis