Malden wrote:Munzio's, Jeff's, Johnson's and Jugular's MRV's each are showing just a snapshot. No hemodynamic at all. Pictures don't represent veins - they represent dye flow inside the some of the veins. And that's not the same - at all.
In contrary, diagrams on
Figure 8 "Examples of quantitative venous blood flow analysis in the straight sinus (top row) and internal cerebral veins (middle and bottom row) of healthy controls (HCs) and multiple sclerosis (MS) patients who were classified as having a normal (left columns), possibly anomalous (middle columns) and probably anomalous (right columns) venous outflow anatomy. No venous backflow/reflux could be observed in any MS patient or HC."
are dynamic, they measure blood flow in ml/s versus time in msec.
That's much better approach then a ECD and TCCS methods, which are strongly operator-dependent, and intracranial venous blood flow is difficult to measure. In contrast, magnetic resonance venography (MRV) is a non-invasive, sensitive, operator-independent technique for the evaluation of venous anatomy and pathological changes, and is widely used in the clinical setting.
The MRV images are pretty standard front view images showing the veins as the contrast dye goes through them. While you only see one image depicted there is actually a slideshow to view as you can spin around the view point and look at the same stenoses from front and the side. There are more than one image taken and in the ones presented in the report a few are laced together. The stenoses don't play a game of now you see them now you don't
The point I makes about the images used to illustrate the study's findings is thar they all depict a mild stenosis or minor malformation. If these images are typical, and one required a moderate to severe stenosis to qualify, then none of the patients in the study would fit the bill. Certainly, though a venogram looking at all the involved veins might find different, it would be questionable whether these patients would bother with repair.
So I don't know what gives with this study. I really hope Haacke comments about it because he probably has seen hundreds upon hundreds of MRV's fed to him several imaging centers. If this study is true, half of those images would show no stenoses. He would also be able to comment upon what is typical and whether he's looked at 'normal' patients.
Until then I am going to throw it out there that the type of moderate to severe stenoses and malformation seen in our cases are not normal and are far more likely to be found in MS patients.
Has for the blood flow part you are absolutely right - the images are only part of the 'picture'. In my case (I am not sure about the rest) Haacke's report came with detailed blood flow analysis, complete with charts and tables. The difference between his approach and the Dutch study is that the Dutch study measured flow at one point in the cerebral veins, whereas Haacke measures at two locations, the upper and lower neck.
Perhaps the Dutch researchers believe that flow analysis is more relevant upstream than downstream. I would say that the differences are more patent downstream. The other point is that the Haacke analysis shows if the left and right flow is asynchronous and whether the flow from the jugulars is diverted. To me, having these main exhaust pipes to the brain open and flowing well is what's behind the improvements seen in patients undergoing venoplasty.
Edit: I am pasting a link to a Haacke report from the False Creek site, so you can see for yourself the differences in methodology in flow analysis (as well as another image of a patent stenosis or malformation)
http://www.falsecreekhealthcare.com/sha ... n-2010.pdf