Larger lesions have a tendency to coalesce and form confluent lesions. The plaques usually involve the posterior and lateral segments of the cord and they do not respect boundaries between grey and white matter and specific white matter tracts. The plaques are usually wedge shaped with it's apex pointing to the centre of the cord. The plaques are sharply defined and there is no edema in chronic cord lesions. Spinal cord atrophy may be seen with chronic disease.
Contrast enhancement is usually homogenous.
There is a decrease in the mass effect after 3 to 4 weeks with near complete resolution of the swelling after 8 weeks. Brain lesions are usually seen in patients with spinal cord lesions. Increased or unchanged swelling at the end of 3 months would favour a tumour and a biopsy should be considered. Furthermore transverse myelitis is known to relapse. Immune mediated myelitis usually shows a dramatic response to steroid therapy.