A hungarian neuro-sonographer dr. Gyula Panczel has jus published a critical approach to Zamboni's Doppler methodology.
Dr. Panczel is a leader in the Hungarian Neuro Sonograpers Association http://www.neurosonologia.hu/vezetoszer ... x?tmi=1825
I have translated his opinion. (please note that i am not a professional translator!)
Here is what dr Panczel thinks about Zamboni's methodology:
It would be very important to reply to this professional opinion, because in hungary we have just started to organize a CCSVI trial...All pieces of the Zamboni-theory is speculative.
Notes to the Doppler methodology:
there were 5 criteria defined by Zamboni:
1. reflux in the internal jugular and vertebral veins > 0,88s
It is normal to find reflux of 0,22 - 0,78 sec in the IJV in a healthy person. Increasing the reflux time with only 0,1 sec doesn't mean that the vein is stenosed. You can achieve this very small increase simply by pressing the transducer a little bit stronger against the skin. If we find a longer (1,23-6,15 sec) reflux time it is the symptom of valve problems, but Zamboni thinks this longer reflux time is not a valve problem, but occlusion of the vein, which leads to SM. (Zamboni rather thinks that valve problem causes transient global amnesia.)
2. reflux in the deep cerebral veins
Intracranial ultrasound imaging is a complex examination and requires a well trained person.
These veins are almost perpendicular to the ultrasound beam, thats why the cosinus of the angle is close to 0, and that's why we can not expect a significant amplitude. (velocity of flow is about 8-13 cm/s). There are two veins (Galen and Rosethal) joined here. that is why in the farthest part of the Rosenthal vein there is an outward flow, but in the nearest part of this vein there is an inward flow. These two opposite flows can be observed as reflux by an average observer.
3. high-resolution B-mode evidence of stenosis of the internal jugular. (cross sectional area < 0,3 cm2)
We never diagnose a stenosis by B-mode detection, especially not in a vein, because it is easily compressible (when its not thrombolyzed). It is a medical malpractice. The significant assymetry of the IJV is usual and is normal. In more than 60% of observed people the cross-sectional area of the dominant vein is double that of the other veins' area. In more than 20% of observed people this area is smaller than 0,4 cm2
4. flow in the internal jugular or vertebral veins that could not be detected with Doppler:
There is no color signal in the vein
5. reverted postural control of the main cerebral venous outflow pathways.
The IJV can be heavily dilated in an upright position, in Congestive heart failure for example. Zamboni could diagnose a vein occlusion in patients with congestive heart failure. (which is false)
Three crieterias (Nr. 1, 2, and 5) are not the signs of vein occlusion for certain.
Zamboni needs only 2 criteria in order to define CCSVI, which could be:
- a healthy person (Nr.1 positive: with a little bit pressure aplpied with the transducer and Nr. 3 positive: IJV assimetry, normal flow)
- a patient with valve insufficiency (Nr. 1 and Nr. 3 positive)
- a patient with congestive heart failure (Nr1 and Nr5 positive)
- the doctor is not a well trained person.
the most obvious criteria for an occluded vein is the absence of Doppler spectrum, which is not included in the 5 criterias.
In school books the signs of vein occlusion are:
-no color signal
-no doppler spectrum
-above the occlusion dilated vein with fixed wall in B-mode
There are other interesting statements in Zamboni's papers. Above the vein occlusion the pressure is elevated, it would be logical for the wall to dilate, but Zamboni describes narrowing of the walls. The most beautiful thig is 100% sensitivity and specifity, but what can you expect from such a flexible 2/5 criteria system which was well adapted to Zamboni's expectations.
Occlusion of the IJV and the azygos vein is not without symptoms. But there were no clinical symptoms of IJV and azygoUs occlusion observed on MS patients.
None of the Ultrasound pictures published by Zamboni convinced me that a vein occlusion has been observed.
dr. Pánczél Gyula
source: http://www.sminfo.hu/beteg/docs/zamboni_kritika.pdf (in hungarian)
thank you very much