Longitudinally extensive transverse myelitis (LETM) and atrophy of spinal cord following LETM. Spinal cord MRI: sagittal T2WI (A and B) and T1WI (C) from three anti-AQP4- antibody positive NMO patients. A. MRI showing cervical spinal cord LETM with swelling. B. MRI showing LETM of cervical and upper 2/3 thoracic spinal cord. C. Severe atrophy of spinal cord as a consequence of recurrent LETM after 6 years duration of disease.