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This is not a competition between angle correction vs consistency in methodology.  I would have thought that consistency was considered essential in any diagnostics. 
We must, however look in all directions to improve our diagnostic capabilities.  And yes, angle correction considerations are important.
 
T Cunningham, RVT, RDCS
----- Original Message -----
From: [log in to unmask]>Cathy Mankin
To: [log in to unmask]>[log in to unmask]
Sent: Wednesday, September 08, 1999 10:23 AM
Subject: Re: Carotid stenosis.

Bob the data I refered to was from ongoing quarterly QA.  However, we never actually tried to perform our QA based only on grayscale.  Might be interesting to make a retrospective analysis!  However, I still use velocity as my primary diasostic tool for categorization of % stenosis. 
 
We did modify our velocity % stenosis criteria when there was a clear discrepancy between the grayscale findings and the spectral findings.  In many instances the velocities indicated a specific category but the plaque size was clearly not consistent with that degree of stenosis.   Eg: velocity c/w 50 - 80% and visual plaque size in range of 30 - 40%.  In these cases, as Bill said we must ask ourselves why?  Is there a more proximal, distal or contralateral occlusive process, was this vessel previously endarterectomized ICA, etc? 
 
We reported both findings separately then used our best judgement to make a definitive determination of the degree of stenosis.  We reported this in a range that generally bridged both the velocity and visual findings.   For instance, in the above example it would have been interpreted as "probable 40 - 60% ICA stenosis". 
 
I absolutely agree with you Bill in regard to consistency  being more important than use of 0 - 60 vs 45 - 60 vs 60 degree angle correction.  And I also agree that it is wrong to lessen our accuracy by calling a 50% lesion of the bulb normal c/w the distal diameter just to correlate with angio.  Rather we should understand the methodology differences so that we may benefit from the QA process.  We are not always comparing apples to apples. 
 
For the most part I too go with the flow!!!
 
Cathy Mankin, LPN, RVT