Baracchini et al. Ann Neurol. 2011 Jan;69(1):90-9. doi: 10.1002/ana.22228.
Fifty consecutive patients presenting with a clinically-isolated syndrome (CIS) underwent extracranial and transcranial venous echo-color Doppler sonography (ECDS-TCDS). Those with results suggestive of CCSVI underwent selective venography (the gold standard for diagnosing diseases of blood vessels). Fifty healthy age- and gender-matched controls were studied. Findings: transcranial venous echo-color Doppler sonography (TCDS) was normal in all PwMS. Selective venography performed in 7 of the patients with abnormal TCDS (1 denied consent) did not show venous anomalies. These findings do not support a cause-effect relationship between CCSVI and pMS.
"One criteria of causation is that the causative factor has to have the correct temporal profile in relation to the onset of the disease that it is meant to be causing, i.e. it has to predate the onset of the disease. These data suggests that CCSVI is not present prior to the onset of MS, as it is not present at the earliest event CIS, therefore it cannot be causing the disease. Again these results will need to be confirmed in ongoing studies."