Imaging diagnosis-CT myelography in a dog with intramedullary intervertebral disc herniation.

A 5-year-old Chihuahua was examined for peracute pain and paraparesis. Neuroanatomic localization was consistent with a symmetric T3-L3 myelopathy. Computed tomography (CT) of the T9-L5 vertebrae was normal. Myelography disclosed attenuation of the subarachnoid space from T11 to L1, consistent with spinal cord swelling. CT following the myelogram disclosed a focal area of intramedullary iodinated contrast medium at T13-L1. At surgery, intervertebral disc material was removed from the spinal cord. Based on the findings in this patient, intramedullary disc herniation should be considered a cause for focal intramedullary contrast medium accumulation.