Thoracic myelogram and post myelogram CT of thoracic spine. No clinical data is provided. Post myelogram CT of thoracic spine:Axial helical CT of thoracic spine from T1 through the T12 after a thoracic myelogram were obtained.Images in both supine and prone position were obtained. Sagittal and coronal reformatted images of both of the series were also obtained.Examination demonstrates slight ectasia of thecal sac at T6 and T7 levels and to a lesser degree slightly superior and inferior to these levels.There is a slight anterior displacement of thoracic cord at this level. Both axial images in supine and prone projection demonstrate a thin layer of contrast anterior to the cord in this region. Be caliber of the cord remains normal otherwise throughout the rest of thoracic region. The exact etiology of this lesion is not clear however possibility of an anatomical variation of mildly ectatic thecal sac with resultant pulsation of CSF on the cord with anterior displacement.Other possibilities of arachnoid cyst within a permeable membrane, thoracic cord herniation through a dural tear or adhesion are considered highly unlikely considering patient's past history to support this diagnosis and the appearance of this finding on myelogram, post myelogram CT and MRI.Comparison off supine and prone images demonstrated no definitive change in the position of the cord however this is not particularly abnormal considering the slightly exaggerated kyphotic deformity of thoracic spine in this patient.
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