Thanks Doug,
I like the cake analogy... If I am baking a cake and I don't follow the recipe the same way I did it the last time I will get a different cake.
Heel toe???? LOL. You Viking.
In a message dated 01/08/10 15:06:36 Pacific Standard Time, [log in to unmask] writes:
Nice Giselle!

I concur... I've tried that in the past. Insonate your own CCA with 60 degree angle, then heel-toe to get it "wonky". :) then angle correct at, say 45 degrees and note the velocity difference.  Reproduction of results in the same patient is impossible, if the angles are always different.  Especially if one sonographer scans a mid cca at 60 degrees, the ica at 45.  Then the same patient is scanned later and sonographer "b" scans the mid cca at 42 degrees and ica at  40 degrees.  Maybe this makes no difference clinically in the normal or severe patient, but the moderate stenosis thAt now is being called severe is now in the que for serial follow ups, or god forbid an unnecessary CEA?  At the risk of sounding "hoity toity" (another medical term), in  going on 19 years, I can count on one hand (all in the early years) the number of times I did NOT use 60 degrees on a non-abdominal artery.  Between steering angles and heel-toe I have always mAintained 60 degrees, parallel to flow/wall.  BTW.. 60 degrees is the angle our diagnostic criteria is based on. So doesn't it render it inaccurate to a "degree" If we scan at different angles?  Jean Primozich (? Spelling, and I believe it was her) once said in a lecture many years ago "when I die, my tombstone is going to be placed at a sixty degree angle!". She is very adamant about the angulation as well!

Doug Marcum
*Advanced Ultrasound Consultants
*Global Vein Solutions
[log in to unmask]
Sent from my iPhone

On Jan 8, 2010, at 4:25 PM, "Giselle Barnes BS,RVT" <[log in to unmask]> wrote:

I believe that most of the criteria we use was written for a 60 degree angle (with certain exceptions like renal parenchyma and TCD where we assume a 0 degree angle because that is how the criteria was written). Velocities taken at lesser angles will yeild a lower recorded velocity. Try it. Line up parallel to a vessel wall and take a velocity at 60 at 45 and at 30 degrees. You will get different calculated velocities. We aren't really looking for the most accurate velocity (which you would get at 0 degrees) but we are looking for focal velocity increases. If you have angles all over the place then you information will be wonky (a scientific term) and you can undercall disease... especially if your reading doc is looking for 125 cm/s or just looking at a ratio....
Vascular ultrasound is an art, but it is also science. To achieve reproducible results you gotta follow the protocol the same way every time (or as close to it as you can get)
If you use a velocity less than 60 degrees you should note it. This way when the next tech comes along to follow you up in 6 months or a year, they know what you did....

-----Original Message-----
From: Cyndi Lufkin <[log in to unmask]>
To: [log in to unmask]
Sent: Fri, Jan 8, 2010 1:03 pm
Subject: Re: Am I old school now?

OK- so next question: Yes, I insist that angle is parallel to vessels, of course.  Are you fols out there at 30 or 45 degrees notating this on exam worksheets and even prehaps carrying over that info to final reports that are distributed to the masses?
My rules:
1.  Work incredibly hard to get 60 or zero parallel to vessel walls.
2.  If it simply cannot be done, then minor deviations allowed as long as they are clearly documented on images and reports, so all involved is aware.

From: Joe Swenson <[log in to unmask]>
To: [log in to unmask]
Sent: Fri, January 8, 2010 3:54:35 PM
Subject: Re: Am I old school now?

If the angle correct is set parallel to flow, the sampled velocity will be accurate, regardless of what the angle is -- 0, 60, 45, 70 etc. The issue is that the greater the angle utilized, the greater error will be if you are not exactly parallel to flow when the velocity is Sampled. If your angle correct Is off parallel , from flow direction, by 5 degrees the error will be greater at a 70 angle as compared to a 60 angle. pound per pound, bigger angles have the potential for bigger errors in calculated velocity.
Sent from my Verizon Wireless BlackBerry

From: Cyndi Lufkin <[log in to unmask]>
Date: Fri, 8 Jan 2010 11:08:29 -0800
Subject: Am I old school now?

I reviewed the archives and followed debates on 11-2003 on Doppler angle of correction. My question is this: Am I being too strict on staff to insist that they do their best to remain as close to 60 degrees as humanly possible even on tough abd/renal cases?  I am a 60 degrees and zero degrees kind of gal ( I do allow them very minimal deviations but never in the range of between 45-15 degrees).  My younger techs argue that when preparing for vascular registry, a source or sources says anything less than 60 degrees is ok. 
My primary argument is that with a lab our size, reproducibly would be a huge problem!  Secondly, I have killed myself all these years to go after 60 oro 0 lol.

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