Radiography of posttraumatic syringomyelia.

Posttraumatic syringomyelia was studied in 15 patients. Gas myelography in 12 patients showed a definite spinal cord swelling in 10 and a probable cord enlargement in two. Plain spinal computed tomography (CT) in four patients demonstrated intramedullary radiolucent zones in three. After intrathecal injection of metrizamide in 10 patients, cysts were opacified in eight. Postoperative CT in two patients demonstrated collapse of the cyst in one. Gas myelography shows the extent and site of maximal dilatation of the cyst where a shunt can be placed. CT is less invasive and provides a definitive diagnosis.