Case 26
History:
56 year old male with chronic myelopathy
Findings:
Sagittal MRI images of the lumbar spine showing a fluid fluid level at the bottom of the thecal sac with the most dependant fluid having signal characteristic similar to the subcutenous fat even showing signal loss on the fat saturation sequence. Also notice central cystic dilatation of the conus likely results of inflammatory reaction.
Diagnosis:
Intrathecal Pantopaque
Discussion:
The investigation of the use of the medical imaging agent ethyl iodophenylundecylate, which would eventually be called Pantopaque, began in 1936. Pantopaque results in inflammatory reaction within the subarachnoid space becoming encysted in some cases. Its absorption rate is thought to be around 0.5-3.0 cc per year. Post mortem reported pia-arachnoid adhesions with nerve root involvement.
Being an oiled based contrast media, pantopaque is best evaluated by MRI showing signal similar to fat on all sequences, even saturating on fat suppressed MRI. Care should be taken not to confuse pantopaque with intrathecal lipoma.
References:
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Davis FL. Effect of unabsorbed radiographic contrast media on central nervous system. Lancet , 1956,2, 747-748.
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Adhesive arachnoiditis following lumbar myelography. Skalpe, I.O.Spine.(1978)
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Histological changes in the central nervous system following intraventriuclar administration of oil based contrast media. An experimental study in the rat. Praestholm, J., Klee, J.G., Klinken, L.Radiology.(1976)
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Chronic arachnoiditis after a pantopaque study of the posterior fossa. Mortara, R.H., Brooks, W.H.South. Med. J.(1976)
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Pantopaque mimicking spinal lipoma: MR pitfall. Suojanen, J., Wang, A.M., Winston, K.R.Journal of computer assisted tomography.(1988)
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