Magnetic resonance imaging findings of remnants of an intradural oil-based contrast agent: report of a case.

BACKGROUND: Myodil (iophendylate), an oil-based positive contrast media, now discontinued, was widely used for performing myelography 30-70 years ago. We identified this agent as the explanation for uncommon magnetic resonance imaging (MRI) findings in a patient with thoracic spinal fracture. DESIGN: Case report and literature review. FINDINGS: An 81-year-old man complained of back pain after falling down stairs. Anamnesis revealed that he had undergone myelography with an oil-based contrast agent about 60 years previously as a part of the diagnostic workup for back pain and sudden onset of gait difficulty. Plain radiography of the thoraco-lumbar spine showed a fracture of the eleventh thoracic vertebra and a radio-opaque, oval shadow at the level of the T9-T10 vertebrae. Many small radio-opaque dots with the appearance of a string of pearls were seen from T8 to L3 vertebrae. MRI revealed a sharply demarcated intradural extramedullary mass, of approximately 5 mm in diameter on the left side of the dura in the region of the T9-T10. The mass showed high signal intensity on T1-weighted MRI, and low signal intensity on T2-weighted MRI. CONCLUSIONS: Increased awareness of this rare presentation of procedures performed in the past is essential when atypical radiographic images are encountered. This case illustrates rare sequelae of Myodil use manifesting decades after administration.