Persistent Oil-Based Myelogram Contrast Agent Identified on Airway Evaluation

A 70-year-old female was referred for airway evaluation, and the referring doctor's notes mentioned obstructive sleep apnea. She had undergone a myelogram at approximately 20 years of age.

The radiologist identified numerous round radiopacities of very high density scattered throughout the skull, mainly along the skull base and predominantly on the right side. The radiologist believed these to be persistent oil-based contrast agent from the myelogram performed approximately 50 years prior.

The radiologist noted that oil-based contrast agents used in that era can persist for decades, unlike modern water-soluble agents, and that myelography has largely been supplanted by MRI, making this an exceptionally uncommon finding.