Dr. Lorne Brandes on the difference between the German doppler study and Dr. Zamboni's US technique--(he actually had sonographers read the papers instead of board postings) it's all about methodology--
link to article
How do we account for this stark contrast? While the populations of MS patients and healthy subjects appear to be reasonably similar in all the studies, at least two major differences in methodology could account for the negative findings in the German/British study:
As opposed to the other studies, it only examined the jugular veins high up, near the angle of the jaw, where additional veins, called collaterals, often branch off the jugulars to maintain blood flow even if there is a blockage. Moreover, as the exam was limited to the top of the neck, it would not have picked up decreased blood flow due to severe jugular narrowing lower down, especially at the base of the neck, near the head of the collar bone, where vein anomalies often occur and there is little or no collateral circulation to maintain blood flow.
It assessed jugular vein narrowing in the “sagittal” plane (the ultrasound probe is placed parallel to the length of the vessel). The Zamboni technique uses the “transverse” plane ( the probe is placed at a 90 degree angle to the length of the vessel) to look for narrowing, webs, or abnormal valves that Dr. Zamboni believes are often missed in the sagittal plane examination.
Thus, as exemplified by all the examples cited, no matter what field of science and medicine we consider, even minor differences in how studies are conducted can, and often do, produce opposing results. This leads to confusion, debate and, all too often, strong disagreement over the “right answer” to crucial issues.
However, in the case of CCSVI, I believe that there is a simple solution to this dilemma: when looking for vein abnormalities, every study, whether involving ultrasound or MR scanning, should follow the technical methods developed by Dr. Zamboni; be blinded to prevent observer bias; and always include selective venography, where dye is injected into the vein and an X-ray taken. It is the gold standard for detecting anatomical vein abnormalities against which all other techniques must be compared.