Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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June 25, 2012
Radiation Myelopathy (RM)
- RM is a rare complication of therapeutic irradiation (doses > 50 Gy), characterized by demyelination, loss of axons, and focal necrosis.
- RM is of two types: 1) early and transient, and 2) delayed and permanent.
- Cancers most often associated with RM include nasopharyngeal cancer and mantle lymphoma (when Rx with concomitant intrathecal chemotherapy).
- Key Diagnostic Features: Acute stage (8 months to 3 years): An expanded cord corresponding to the radiation field is seen appearing hypo- to isointense on T1WI and hyperintense on T2WI . The vertebrae in the radiation field will show changes consistent with fatty marrow replacement. A variable enhancement pattern ranging from no enhancement to ring or irregular enhancement surrounded by edematous cord is seen. Chronic stage (> 3 years): Cord atrophy.
- DDx: Transverse myelitis, NMO, MS, ADEM, cord infarction
- Rx: No Rx. But risk can be reduced by judicious selection of radiation port.