1426 Multiple Sclerosis Journal 19 (11) on the evening news, reiterating the apparent efficacy of the “liberation procedure”, any reservations about the procedure almost invariably being preceded by an opening shot of a patient rising from a wheelchair. The ongoing pressures (including those generated by some members of Parliament and some provincial governments) were such that within a few months CIHR modified its initial cautious stance by calling for proposals for smallscale treatment trials despite the ongoing ambiguity about the viability of the CCSVI hypothesis. These trials have now received initial funding. There is a bewildering array of techniques for noninterventional examination of the venous drainage of the central nervous system, and as has been most recently illustrated in the study from the Italian group, 2 a distressing level of intra-observer disagreement in interpretation of ultrasound data. However, it is also clear that there are enormous variations in normal patterns of cerebral venous drainage within the healthy population, and that interpretation of patterns of venous drainage and venous obstruction can be highly subjective, subject to observer bias, and discrepant from institution to institution, depending upon the particular technology used for assessment. The particular strength of the investigations by the Texas group and the Italian consortium is the meticulous care that was taken in both cases to achieve blinding to diagnoses both of ultrasonographers performing the studies and of the individuals reading the ultrasound images. The study by the Italian group2 represents the largest multi-centered trial to date, and the paper by Brod et al. 1 extends the ultrasound observations of the Texas group on a large group of patients and controls3 to studies using the more interventional techniques of contrast enhanced magnetic resonance venography and transluminal venography on a small group of patients with MS. Although the latter studies are not bolstered with the sort of statistics that one would like to see comparing patients with controls, the unsurprising conclusion is that venous anomalies and pressure gradients within veins were only rarely seen in the MS patients examined. In short, these two studies provide the most convincing evidence yet available that cerebral venous anomalies do not exist with any increased frequency in patients with MS. The scientific process, in the face of enormous pressures, seems to have done its work. In light of these carefully done studies it should now be a settled issue that CCSVI does not offer a plausible explanation for the pathophysiology of MS.

Is there a remaining justification for ongoing clinical trials of treatment of CCSVI? Interventional clinical research trials are always fraught with ethical issues. Foremost among these is the requirement for equipoise, 14 the ability to make both a theoretical and clinical case that a putative new treatment might be better than currently available treatments. From a theoretical standpoint there would now appear to be no justification for ongoing treatment trials, given that all well-controlled and well-blinded studies, including those reported in this issue of the MS Journal,