The diagnosis of multiple sclerosis can be challenging, with misdiagnosis a problem. Recognition of the central vein sign in white matter lesions of the brain may improve diagnostic accuracy.
Patient selection: possible multiple sclerosis or clinically isolated syndrome
On histology lesions of multiple sclerosis occur around a central vein, and improved MR imaging can visualize the finding.
The central vein sign on an imaging study is defined as a white matter lesion with a central intralesional vein. It consists of a thin hypointense line or dot, with a diameter less than 2 mm. The CVS should be seen in at least 2 orthogonal planes, and it should appear as a thin line in at least one of these planes. It should be positioned centrally in the lesion, regardless of the lesion's shape.
MR method: FLAIR* (T2-FLAIR and T2*-weighted segmented echo planar imaging)
A lesion should not be used for evaluation if it small (< 3 mm), confluent with another lesion or poorly visible. A lesion with multiple veins should also be excluded.
Central vein positivity on an imaging study may be based on a variety of criteria, such as total number detected or percent of MS lesions showing a central vein sign.
In multiple sclerosis the CVS-positive lesions are more often located in periventricular white matter.
CVS lesions can also be seen in other conditions:
(1) neuromyelitis optica spectrum disease
(2) systemic lupus erythematosus
(3) migraine headache
(4) diabetes
One distinction is that in multiple sclerosis and clinically isolated syndrome and multiple sclerosis the percentage of lesions showing the CVS is higher (median 0.5 to 0.6, vs < 0.2 for others).
