Computed tomographic metrizamide myelography in syringohydromyelia.

Four patients with surgically verified syringohydromyelia, including 2 with and 2 without a collapsing cord, were examined with computed tomographic metrizamide myelography (CTMM). When the cord is collapsed, or a contrast-containing cyst is observed on the scan, no further examination is necessary. If the cord is not collapsed, it is difficult to differentiate an intramedullary cyst from a tumor. Flattening of the ventral border of the cord in the supine position, coupled with an increased transverse diameter and alteration of the normally smooth, oval shape are suggestive of syringohydromyelia.