Chronic cerebrospinal venous insufficiency (CCSVI)

Photo: Closeup of microscope
CCSVI is a term used to describe the narrowing of veins in the neck, which has been suggested to affect blood flow out of the central nervous system.

A link between CCSVI and MS was first suggested in 2009, but this has since been challenged. Trials of treatments for CCSVI found that it did not reduce MS symptoms or damage on MRI but might worsen relapses and activity on MRI scans.

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