Keep in mind also, that in Europe their UT/Doppler equipment is more advanced than our average UT equipment, simple $$ thing.
Then again we run headlong into the issue of training:
(copy)
The four basic types of Doppler ultrasound are:
"Bedside" or continuous wave Doppler. This type uses the change in pitch of the sound waves to provide information about blood flow through a blood vessel. The doctor listens to the sounds produced by the transducer to evaluate the blood flow through an area that may be blocked or narrowed. This type of ultrasound can be done at the bedside in the hospital with a portable machine to provide a fast estimate of the extent of blood vessel damage or disease.
Duplex Doppler. Duplex Doppler ultrasound uses standard ultrasound methods to produce a picture of a blood vessel and the surrounding organs. Also, a computer converts the Doppler sounds into a graph that gives information about the speed and direction of blood flow through the blood vessel being evaluated.
Color Doppler. Color Doppler uses standard ultrasound methods to produce a picture of a blood vessel. Also, a computer converts the Doppler sounds into colors that are overlaid on the image of the blood vessel and that represent the speed and direction of blood flow through the vessel.
Power Doppler. Power Doppler is a newer ultrasound technique that is up to 5 times more sensitive in detecting blood flow than color Doppler. Power Doppler can get some images that are hard or impossible to get using standard color Doppler. But power Doppler is most commonly used to evaluate blood flow through vessels within solid organs. Blood flow in individual blood vessels is most commonly evaluated by combining color Doppler with duplex Doppler. Together, these techniques are able to provide better information on the direction and speed of blood flow than when they are used separately.
Yet:
Objective. The main goal of this study was to determine end users’ knowledge regarding safety aspects of diagnostic ultrasound during pregnancy. End users’ attitudes toward the use of ultrasound in low-risk pregnancies were also assessed. Methods. A questionnaire was distributed to ultrasound end users attending review courses and hospital grand rounds between April and June 2006. Results. One hundred thirty end users completed the questionnaires (63% response rate). Sixty-three percent were physicians (n = 84), most of them obstetricians (81.7%). About 18% of participants routinely performed Doppler ultrasound examinations during the first trimester. Fifty percent of end users thought that the number of ultrasound examinations in low-risk pregnancy should be limited to 1 to 3 (mean ± SD, 2.6 ± 0.9). Almost 70% disapproved of "keepsake/entertainment" ultrasound. Although 32.2% of the participants were familiar with the term thermal index, only 17.7% actually gave the correct answer to the question on the nature of the thermal index. About 22% were familiar with the term mechanical index, but only 3.8% described it properly. Almost 80% of end users did not know where to find the acoustic indices. Only 20.8% were aware that they are displayed on the sonographic monitor during the examinations. End users with higher knowledge of safety issues thought that there should be limitations on the number of ultrasound examinations in low-risk pregnancies (odds ratio, 3.3; 95% confidence interval, 1.1–10.0; P = .028). Likewise, these end users were more likely to respond that ultrasound might have adverse effects during pregnancy (odds ratio, 3.2; 95% confidence interval, 1.1–12.5; P = .045). Conclusions. Ultrasound end users are poorly informed regarding safety issues during pregnancy. Further efforts in the realm of education and training are needed to improve end user knowledge about the acoustic output of the machines and safety issues.
Granted, that's a poor example from pregnancy exams, but just illustrates that times x when we are talking about reflux going back up into the brain which is the *real* issue, not merely pressure gradients which can be transient.
Point being it is going to take some time, maybe a long time before our average UT Tech can sit you down, flip on a machine, and dx CCSVI related reflux or anything close to that...
Mark.
Note that 81 % of "end users" were OB's...
As has oft been mentioned in here, our lack of a substantial knowledge base in dx'ing jugular stenosis/reflux, leads to at least see what we know, don't know about dx'ing carotid stenosis which is obviously more prevalent and examined. Considering that this was only in 2002, and the amount of variability involved even within a particular laboratory, having umpteen thousands of MS patients taking instructions into a tech or MD to get screened could lead to thousands of different interpretations. It's dicey to say the least...
http://radiology.rsna.org/content/229/2/340.full.pdf
Diagnostic Strata
Methods of Reporting
Issue.—Methods by which the degree of ICA stenosis is reported vary from laboratory to laboratory, as well as within some laboratories. Some report an estimate of the specific percentage of stenosis,
others stratify their estimates into five or six diagnostic categories or gradations of stenosis.
Recommendation.—Doppler US cannot be used to predict a single percentage of stenosis. Therefore, the consensus panelists
strongly recommend the use of defined diagnostic strata.
Laboratories should establish protocols for stratifying the degree of ICA stenosis, and, once established, these criteria should be consistently
applied.
Doppler Measurement Variability
Although investigators have confirmed that the average Doppler velocity rises in direct proportion to the degree of stenosis
as determined with angiography (18,26), there are very wide ranges of
Doppler values around those means,which makes it impossible to classify lesions into gradations as narrow as 10%
(Figure) (18,34).
Even in evaluations of the ability of Doppler US to help estimate
the degree of stenosis by using more expanded strata (eg, 50%, 50%–69%, and70% stenosis), the findings have been disappointing. US is most accurate when lesions are classified as being above or below a single level, such as 60% stenosis or 70% stenosis (18).Other issues that need to be addressed include the following:
1. There is considerable variation in Doppler measurements from machine to machine and manufacturer to manufacture.
This should be rectified, because such variation leads to inconsistencies
and inaccuracies in diagnosing ICA stenosis.
2. Phantoms for Doppler US need to be developed to facilitate calibration of Doppler US equipment.
3. Improved methods for calculating velocity with angle correction should be developed to eliminate or minimize theinconsistency in velocity measurements as the Doppler angle
)
