Persistent Oil-Based Myelogram Contrast Agent Identified on Airway Evaluation

A 70-year-old female with a history of obstructive sleep apnea was referred for airway evaluation. 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 base, predominantly on the right side. The radiologist determined 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 indefinitely, unlike modern water-soluble agents, and that myelography has largely been supplanted by MRI, making this an exceptionally uncommon finding.