Superficial Siderosis MRI Cord and Spine: Complications and Associations.
In the previous post we looked at what the appearance of Superficial Siderosis is on MRI.
Hemosiderin deposition on Nerve Roots can result in arachnoiditis.
- Clumping and abnormal distribution of nerve roots.
- The normal symmetric distribution of nerve roots is lost and there is asymmetry in their distribution. (2nd and 3rd images below asymmetric distribution of nerve roots).
- The nerves can also stick to each other resulting in the appearance of an enlarged nerve root (Green arrow).
- Enhancement of nerve roots can occur but is not always present.
- Enhancement is secondary to inflammatory changes induced by the hemosiderin deposition.
- Giving contrast is not essential to making a diagnosis of arachnoiditis in superficial siderosis.
- Superficial siderosis of the cord (Pink arrow) can result in cord oedema (Blue arrow).
- WHY IS THAT? Hemosiderin lining of the cord results in abnormal movement of CSF through the cord. This can result in cord oedema with increased T2 signal in the cord.
- Extra dural arachnoid cysts (Green arrow) can be associated with and result in superficial siderosis (Pink arrow).
- The mechanism is thought to be from a tear in the dura resulting in low grade chronic bleeding resulting in siderosis and formation of an extra dural arachnoid cyst due to a leak from the dural tear.
New MRI Spine Mini Fellowships commencing in July 2021.
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