Wednesday, 13 June 2012


 35 yrs old patient, operated 3 yrs ago for a right frontoparietal high grade astrocytoma and underwent radiotherapy.

Axial GRE sequence: Thin hypointense rim noted on the cortical surface of both cerebral and cerebellar hemispheres and on the surface of brain stem- suggestive hemosiden deposition.

·        Superficial siderosis is the result of chronic and recurrent subarachnoid hemorrhage and the causes include:
1.     Postoperative
2.     Cerebral aneurysms
3.     Vascular malformations
4.     Cervical root avulsion
5.     Hemorrhagic neoplasms
·        CT is insensitive in detecting siderosis, but may reveal cerebral and cerebellar cortical atrophy that is associated with superficial siderosis.
·        The MR findings are dramatic, with the brain surface and cranial nerves outlined by a profound hypointense signal on T2 MR images.
·        T2 gradient echo (GRE) images are very sensitive to hemosiderin deposition and show blooming of the hypointense signal.
·        The source of recurrent bleed may sometimes be located in the spine which should always be screened if no cause is found by imaging of brain.
·        Hemosiderin is a neurotoxic agent that is responsible for neuronal and glial damage resulting especially in eighth cranial nerve damage and cerebellar atrophy that account for the characteristic clinical features of this disorder.
·        The most common clinical manifestations include bilateral sensorineural hearing loss and ataxia.
·        The other features include bilateral hemiparesis, bladderdisturbances, anosmia, dementia and headache.
·        The treatment is directed at the underlying cause.
Reference: Superficial siderosis, Neurology India | Sep-Oct 2009 | Vol 57

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