The U.S. Multiple Sclerosis Society has joined the MS Society of Canada in inviting scientists to submit proposals to study a new theory about a vein condition that may be linked to the disease.

The call comes after CTV's W5 was the first to report on the vein condition discovered by Dr. Paolo Zamboni of Ferrara, Italy. Zamboni had conducted research that he says shows that over 90 per cent of MS patients have narrowed or blocked veins in their necks and chests that drain blood from the brain.

He believes the vein disorder, which he has called Chronic Cerebrospinal Venous Insufficiency (CCSVI), is what sets in motion the neurological symptoms of MS.

He has also found that endovascular surgery to open these blocked veins, a procedure he calls the "Liberation Treatment," leads to an improvement in symptoms and a decrease in new attacks in MS patients. The procedure involves inserting a tiny balloon into blocked veins to "liberate" the flow of blood out of the brain.

Last week Canada's MS Society opened the call for funding of studies to look into the vein theory and possible treatment. On Wednesday, the U.S group said it too would accept proposals and is in discussions with the Canadian MS Society about jointly funding research projects.

"If confirmed, these findings may open up new research avenues into the underlying pathology of MS as well as potential new approaches to therapy. Further research is now underway. The National MS Society has invited research proposals to investigate this lead, and is in active discussions with the MS Society of Canada about the possibility of collaborative funding of CCSVI research," the National MS Society said in a statement.

But it added: "Many questions remain about how and when this phenomenon might play a role in nervous system damage seen in MS, and at the present time there is insufficient evidence to prove that this phenomenon is the cause of MS."

Both MS societies in Canada and the U.S. were initially reticent to support Zamboni's theory, noting that it has not seen enough evidence. But since the W5 report, the groups have been flooded with queries from patients seeking more information.

Dr. Yves Savoie, the president and CEO of the MS Society of Canada, told CTV News last week that investigating CCSVI will not take away money from other promising avenues of MS treatment, such as stem cell research. has now posted a copy of Zamboni's study published in the December issue in the Journal of Vascular Surgery.

In the study, Zamboni's team reports that among 65 MS patients treated with the "liberation" procedure, 50 per cent with the most common form of the disease -- relapsing-remitting -- were relapse-free for 18 months. Among the control group of MS patients who did not undergo the procedure, only 27 per cent went 18 months without an MS attack.

Additionally, scans showed that 12 per cent of patients in the surgery group had active brain lesions -- a sign of active disease -- compared to 50 per cent in the control group.