Section Editor: Sandy Cheng-Yu Chen, M.D.
Taipei Medical University Hospital, Taipei, Taiwan
Lipiodol and Myodil are oily, high-density, iodinated contrast media that were used until the 1980s for myelographic studies. In the procedure, the contrast medium was removed by aspiration after the examination but often not in its entirety. The retained contrast medium can spread to the subarachnoid spaces and stay there for a long time (A and B, arrows). On CT, the retained oil droplets should not be confused with calcifications. At bone window setting, the Lipiodol/Myodil drops maintain a greater density than the bony structures (C, arrows). Differential diagnoses should include neurocysticercosis and tuberculomas.