That's one of the huge issues.
There are two problems. We didn't worry a lot about the variation in the anatomy of neck veins until this happened. That's one thing. And why didn't we worry? It was because there is a huge redundancy in the number of veins and capacity for drainage, and it's normal. The veins have to be able to drain whether you're sitting, whether you're upside down, or whether you're standing. So the neck vein system has often been referred to as the “delta of the Nile”. You can block a number of rivulets, but in the end it drains perfectly. And that's one of the big issues.
So even if there are a number of anatomical differences in patients, we'll have to ensure (a) that these differences are truly, systematically, more numerous than in controls, and (b) that they truly impair drainage. That's why some of the techniques that are going to be used in these seven studies that I keep referring to should give us some information regarding blood flow and the anatomy.
There are also two groups that are doing post-mortem studies on patients to look at the vein anatomy in much greater detail than we've done so far. They will do this by moulding, by injecting silicone into the venous system, by being able to make very accurate measurements. They will be comparing--I can't say healthy controls because it's post-mortem, but comparing normal individuals with people who died from MS.