Imaging of the spinal cord.

Methods of investigation HISTORICAL PERSPECTIVE Air myelography The first contrast medium used to show the spinal cord was air. The first reports of its use to localise intraspinal tumours came from Jacobeus in 1921 and Dandy in 1925.1 The technique was later refined to show the entire spinal canal; this involved complete replacement of the CSF by air and distension of the spinal subarachnoid space.2 Adequate visualisation of the spinal cord usually required tomography. Spinal roots were not shown, and many types of pathology such as vascular malformations or arachnoiditis were either not shown or easily misinterpreted. Despite the fact that the technique was difficult to achieve and very hard on the patient, it remained the preferred method for visualising the spinal cord in many centres until the advent of non-toxic water soluble contrast only just over 10 years ago.