Intrathecal use of Lipiodol^®, a product of iodized poppy seed oil, was first used as a diagnostic tool in 1921 to identify spinal masses. It was later realized to be poorly absorbed by the central nervous system and, in some instances, inducing inflammation leading to arachnoiditis and neurological sequelae. This led to its widespread discontinuation shortly after the association was discovered. With the subsequent introduction of iophendylate-based oils, these complications were seen less often, though arachnoiditis still occurred in <1% of cases. Today, contrast-related complications have nearly vanished due to the universal replacement of lipid-based compounds with water-soluble and gadolinium contrast agents.

CT myelography was traditionally the gold standard for the diagnosis of foraminal nerve compression. While MRI has generally replaced this modality today, CT myelography remains a valuable diagnostic tool, primarily in patients with contraindications to MRI or when MRI is not available. In particular, CT is excellent for distinguishing vertebral osteophytes from soft tissue material within the spinal canal.  The development of water-soluble agents allowed even distribution in the subarachnoid space and excellent depiction of spinal anatomy on post-myelographic CT scanning. Although invasive, myelography will remain a useful tool for the foreseeable future.

This case was submitted with supervision and input from:

Soni C. Chawla, M.D.
Associate Professor
Department of Radiological Sciences
David Geffen School of Medicine at UCLA
Olive View - UCLA Medical Center