Age / Sex : 73 / M

Chief complaint :

Both leg pain

What is your impression?

Two weeks later, you can see the final diagonosis with a brief discussion of this case (Please submit only one answer).

Courtesy : In Sook Lee, Pusan National University Hospital

Discussion

Answer:  

Pantopaque induced arachnoiditis

Findings:

On plain radiography, multiple increased opacity was seen in S1 level.

On sagittal and axial CT images, multifocal high density dot like lesions were seen in the thecal sac and along the dural wall.

On axial and sagittal T2-weighted images, multifocal high SI intradural lesions are noted, and they show high SI on T1-weighted image. Also adhesion of cauda equine and septation of thecal sac were noted.

Differential Diagnosis:

Calcified dural plaques

Calcified hematoma from remote trauma

Arachnoiditis ossificans

Intradural lipomas

Discussion:

• Myodil (From 1946 to 1988, Glaxo)


• Iophendylate, a fatty acid, formerly manufactured by Glaxo Laboratories

 (London, UK)

• also known as Pantopaque in the USA


• oil-based contrast media


• widely used in myelography, ventriculography, and cisternography

     ð used substance until the 1980s, gradually becoming replaced by

         water-soluble media.

• rare side effects of intrathecal Myodil

     ð arachnoid adhesions, cysts causing spinal cord syrinxes, compression,  

         or nerve root irritation

• absorbed very slowly

  ⇒ months or even years, and can remain in the thecal sac for years after

      a procedure

  ⇒ usually appears as intradural dorsal droplets

• MRI characteristics similar to those of fat or blood

  ⇒ hyperintense on T1WI and hypointense to hyperintense lesions on

      T2WI

References:

1. Magnetic resonance imaging findings of remnants of an intradural oil-based contrast agent

 - The Journal of Spinal Cord Medicine, Volume 35, Issue 3, 2012

2. Asymptomatic thoracic Pantopaque cyst mimicking an intradural extramedullary lipoma on MR images

        - Europian spine journal, Volume 22, Issue 3, 2012