Both responders are nuts, and it makes me despair of this field ever getting it together and achieving any kind of consistency, as there are so many instant experts. God help us.
From: UVM Flownet on behalf of linda sulzdorf
Sent: Tue 6/5/2007 10:06 AM
To: [log in to unmask]
Subject: Doppler vs measurement criteria for grading carotid disease.
I'm teaching an online sonography program and as part of the coursework, I'm introducing the students to venous and carotid exams. My first discussion assignment asked what criteria the students' departments were using to grade carotid lesions and how the surgeons used this criteria for patient treatment decisions.
One department is essentially using the Stavros Doppler criteria for grading the degree of the diameter-reducing stenosis, but added the ICA/CCA ratio of 4.0 (Moneta) to differentiate between greater or lesser than 70% diameter reduction. Then, if severe plaquing is identified, a transverse image is used to determine the percent of area stenosis. When I asked how these two criteria were integrated, these are the explanations I received from the clinical instructor and student:
Clinical Instructor: "Area measurements are used at virtually every facility I have worked at, and as a traveler I have worked at many. With the advent of pdi obtaining transverse area measurements is more accurate and precise than older methods i.e. Diameter measurements which do no account for lateral plaques......I personally think that area measurements are more precise albeit more time consuming than diameter measurements. These measurements are more easily compared to cta/mra images which are measured in the same manner..... I am trying to help ****** understand that Doppler is a poor indicator of low grade stenosis and is not accurate in establishing a reasonable estimation of the actual percentage of stenosis. We currently use the criteria established by The society of Radiologist in ultrasound."
Student: "The manner that these measurements are obtained is identical to that used in echocardiography and is also used in the cardiac cath lab to determine ejection fraction, I believe it is based on the Simpson's equation so I think that these measurements are accurate and my clinical instructor believes them to be more precise than velocity alone. He says that diminished cardiac output, aortic insufficiency and overall poor arterial health effect velocity but have no effect on the area stenosis. I am told it is one of the many tools used to a thorough carotid study. Diameter stenosis is much less involved and much more innaccurate because of lateral plaques not in the line of measurement.... makes little sense to me that what is an acceptable measurement in echo would be invalid in vascular ultrasound. According to my clinical instructor this is a common practice at several large nationally known vascular labs he has worked at.
OK, so the question I have is obviously, what is common practice in vascular labs? I confess to have been brought up to use Doppler criteria for diameter reduction and essentially follow the Strandness criteria with the addition of Moneta's ICA/CCA ratio to select those patients with a greater than 70% diameter-reducing stenosis. When we were performing angios, we internally validated this criteria and realized the difficulties with trying to add the Moneta criteria to the Strandness criteria, because one measured one thing and one measured another. (i.e., at the site of stenosis as opposed to a comparison with a normal ICA at a site distal to the lesion). So, am I way behind the times and should be put out to pasture? Please feel free to flame me....I'd much rather be enlightened than ignorant.
Thanks in advance and forgive me for my long post.
Linda Sulzdorf, RDMS, RVT, BSVT
Sonographer and Instructor
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