Thank you dR Evans. Good morning everyone. We are now going to move up the body to talk about the extra cranial carrot, a duplex exam. So the components of this exam include extensive grayscale imaging to look for plaque and we try to characterize plaque as well as best as we can. We also do color and spectral Doppler interrogation at minimum. We're gonna want to evaluate the distal common carotid artery just before the bifurcation because we're gonna use that for velocity ratios. Multiple sites in the internal carotid artery, at least one site in the external carotid artery, at least one site in the vertebral arteries. And some protocols also include the subclavian and a nominate Arteries. And very importantly, we don't want to spot check. We really want to systematically march through the vessels. In general, we try to keep our angle of incineration constant, usually 60°, works out. We want to be parallel to the vessel wall and the flow channel, especially the latter is more important, especially in tortuous city, But we certainly never go above 60°. And if we find an area of color flow disturbance, that's where we're really gonna want to dive in there and get multiple spectral Doppler samples to identify areas of stenosis. Now, dr Evans showed you this slide earlier. This is called the spencer Reid curve. This is the relationship between peak systolic velocity and percent diameter reduction. And you can see that when you have about a doubling and velocity that correlates to about a 50% stenosis. A quadrupling a velocity, about a 75 or 70% stenosis. And this relationship holds true until we get to very severe degrees of stenosis 99%. And then you do something called falling off the spencer reid curve. So you can actually have a low or normal velocity in the setting of a really critical near exclusive lesion. We call those near on your conclusions. And this relationship has been specifically validated versus catheter and geography by multiple investigators over the years. And I briefly want to mention because this does show up on board exams. There's different ways for measuring percent stenosis on our correlative gold standard of angiography. And the world has really moved toward the Nasa methodology where we use the standard reference diameter being the distal diameter of the I. C. A. Beyond the lesion. An older school method was trying to estimate the reference diameter at the lesion but that's more prone to air. It's harder to measure there. So the world has really moved to Nasa based methodology. The tricky thing is when you compare Nasa and E. C. S. T. E. C. S. T. Tends to call things a higher degree of stenosis because you're measuring it a dilated bulb segment compared to an asset. But we're now doing Nasa based methods. These are the original carotid duplex criteria that came out of the University of Washington led by dR Strand is the founding father of the vascular laboratory. And you can see here the different categories. But this is where this PSV of 1 25 centimeters per second came from. That was an E. C. S. T. Based measurement correlated to angio is using that older method. But you can see a PSV of 1 25 was sort of the cut point for greater than 50% stenosis. Um Here we also see another common parameter that an end diastolic velocity above 100 and 40 centimeters per second indicated a very severe stenosis Of a greater than 80%. These are criteria that are very commonly used throughout the United States. We use them in our university hospitals vascular labs. These are the S. R. U. Consensus criteria I think these are criteria to know for the registry exam and we have different categories. We have normal no plaque and normal PSV less than 100 and 25 centimeters per second. We have plaque but less than 50% stenosis. So our PSV is less than 1 25. But we see plaque. We have a 50 to 69% category which you can see here is a PSV above 1 25. And then I see a two CC. A ratio highest PSV. In the I. C. A. Divided by PSV. In the CC. A. Right before the application above two we have a greater than 70%. This is derived from the Greg. Mineta's work and the Nasa trial group of a PSV above 2 30. Usually with an I. C. A. To C. C. A PSV ratio above four. There's also another parameter of an E. D. V. Above 100. Then we have those near occlusion which is those falling off spencer reid's I mentioned and then we have occlusion. Now dr liars and I were involved in a project just recently published that came out of the inter societal accreditation commission where we wanted to actually validate those S. R. U. Criteria versus catheter angiography. But we decided to use nascent methodology in measuring our catheter angiogram. So this was actually a multi center study. We looked at almost 300 I see a angio correlates from 167 patients. And we had blinded and geographic interpretation and also blinded reading using the S. R. U. Consensus criteria and then a bunch of statistical analysis looking at the individual velocity parameters using R. O. C. Analysis and percent stenosis. And we found a couple of things. We actually found that expert reader interpretation using that S. RU consensus chart resulted in major overestimation of parents sense stenosis versus angio for both 50 to 69 greater than 70% lesions. And then we kind of ground out the numbers with statistical analysis and we were looking for parameters that had at least 90% sensitivity, 80% specificity and 80% accuracy for I see a stenosis by duplex versus angio. And we found that PSV alone of 1 25. Really inadequate for the greater than 50% and it had very very low um specificity and accuracy. We found the best single PSV parameter was 1 80 centimeters per second. But you could use lower PSV's between 1 25 and 1 80. If you also had the I. C. A. Two CC. A ratio above two, We unfortunately didn't have enough cases with a stenosis greater than 70% to make definitive conclusions. But this led to a communication from I see vascular testing about six weeks or so ago that recommended some updated use of these data in the S. R. U. Chart. So you'll now see if you're going to use PSV alone for greater than 50 180 centimeters per second. But there are cases where you're going to have a 50 to 69% lesion where your PSV might be between 1 25 and 1 80. But you really must make sure that I see a two CC a ratio is also greater than two. And the I. S. C vascular testing recommended adoption of these these new parameters. Okay quickly back to the RPV eye exam. So here's a case you'll interpret as normal and I probably want to use the old S. Ru consensus if you're taking the exam anytime soon. I don't know how quickly things will be adapted from that. I see communication but our PSV is 80 centimeters per second. No plaque seen. This one is normal. Here's a here's a case where on the gray scale image you see some plaque on the far wall, but color flow is normal. Beautiful spectral window. Um PSV 100 centimeters per second. This is a less than 50% lesion. Now here's a 50 to 69% lesion using the old criteria. Okay. Uh this is a P. S. V. Above 1 25. It's 100 and 39 centimeters per second. Our ratio is 1.7 little aliasing of the color signal. I think if you're going to take the exam anytime soon, this will still be 50- 69% lesion. And here's a lesion where we have more extensive plaque, both near and far wall color flow abnormality, spectral broadening PSV 200 centimeters per second. It's above that 1 80. Our ratio is clearly above two. That's a solid 50 to 69. And here's a more severe lesion here. More extensive plaque. You can see the Luminal encroachment. Uh PSV is 380 centimeters per second. I see a to C C A PSV ratio above four. That is a solid greater than 70%. And I think here you can throw in that old strand. This parameter that E. D. V. Is above 140 centimeters per second. You could probably call that a greater than 80% lesion. Now when you have a severe lesion like that. Not only do you want to see post hypnotic turbulence As shown here on the spectral display. We have picket fence above and below. We've got um when my friend Tammie Rubin calls the bart Simpson sign. Bart's hair. A lot of a lot of turbulence there. And then as you move beyond, you lose the turbulence but you lose energy and we have that dampened harvest Tartus waveform, all coral correlate with a severe stenosis. Quick RPV. I. Question which of the following is suggested by this image. Is this proximal common carotid artery stenosis? Subclavian stenosis with steel left. I see a occlusion or left E. C'E. Occlusion. What's your answer? See, Okay, this is an externalized common carotid artery waveform in the setting of an I. C. A. Occlusion. And you really want to verify that by turning down your color settings, seeing if there's trickle flow in there and you can use color power and geography as well. Uh I want you to be sure as dr Evans mentioned earlier as you're studying for the exam. Review that content online and specific competencies that you need to know how to do. This was just updated as of october 1st. So please review the new RPV. I. Content outline. Gonna hit on a few high points from the outline. Next duplex after carotid stenting stents are generally well seen on grayscale imaging, they're starting the C. C. A. They go into the I. C. A. They may jail the ec. A causing a little bit of a velocity shift in stenosis there it's very common to see plaque outside of the stent abutting the vessel wall. Our operators don't post dilate those carotid stents because they're worried about getting this phenomenon called the cheese grater phenomenon. So not uncommon to see higher velocities within the stent even though the stent is patent. Um Some of these stents also have a closed cell designed with some altered compliance that increases velocities. So you really need separate criteria for carotid instant re stenosis. This process also has a different natural history than atherosclerotic disease. Intimate hyperplasia does not m belies. So we have much higher thresholds at which we're going to intervene. But these are various published criteria for him a dynamically and clinically significant instant re stenosis. And you can see 80 or 70% cut points and usually a PSV over 300 to 340 centimeters per second. A meta analysis found a good cut point of 3 20 for a significant incident re stenosis. And again you see these ratios around four and here's a nice older example I had of you can really see that neo intimate hyperplasia on the color power and grayscale image. And then down below on the spectral display very high velocities over 100 440 centimeters per second briefly. Wanna mention duplex after endarterectomy. Most operators patch so very common to see a slightly dilated segment where you have this patch. And these patches also can sometimes degenerate and become aneurysm all over time. But because that patch segment is dilated as you move beyond the patch into the more normal diameter, I see a you might get a little step up in velocity. It's the pinching of the garden hose. So we that's really a patch. Native vessel diameter mismatch. That's not re stenosis or internal hyperplasia. And dr abu Rahma and colleagues have shown you need slightly higher velocities for calling a significant stenosis in a patched I see a um also gonna want to look for clot a dissection overtime aneurysm all degeneration. And here's a case where you have a bigger patch on the on the left and then some tapering and you can see a slight velocity shift 77, cm/s. Very common beyond a patch segment briefly. Wanna mention non atherosclerotic disease. This does show up on the exam of fiber muscular dysplasia. Top of mind in my case, these are women with pulse, it'll tinnitus headache hypertension. We're gonna see the velocity shifts at mid to distal vessel. So you you really want to image that distal. I see a so are our wonderful technologists know they got to get the curve transducer an image very high up in the neck. Very importantly, the the hallmark here is turbulence really want to see that turbulence on the color display. That's why the patients here, the breweries in their heads. And again, very importantly for F. M. D. We do not use the chart for FMD. That chart is not validated at all for FMD. And honestly the numbers are meaningless. I have patients who are fine through velocities of 400 centimeters per second for a decade. So instead of putting the chart numbers on, you want to use something like elevated velocities, turbulent flow and beating noted at the mid to distal vessel consistent with um FMD. And here's some beautiful images from our technologist, Melinda. I think you recently had that beautiful color power on the bottom right there showing the beating. Thank you. Melinda or other entity that you should know is large vessel vasculitis dr Carmen showed you one of these in the subclavian arteries here. The clues are the grayscale findings. The plaque looks atypical for atherosclerosis. It's a circumferential wall thickening or a hippo ico halo of adama shown on the top image also rarely do you calcify acutely. Sometimes you do later on. But the other clue is it's the location. It's not at the bifurcation. It's in the proximal to mid common carotid artery. Excuse me. And it's more diffuse and we're looking for turbulence and velocity shifts just as we always do consistent with human endemically significant stenosis in G. C. A in particular, you can get very long segment lesions and very important if you think this is a typical for a thorough and it could be vasculitis. This should be noted on the report because the management pathways are so different. And sometimes just the technical findings that the wall thickening suggests possible Vasculitis may take the order and clinician down a whole different path briefly. Wanna mention subclavian arteries. We always get a vertebral Doppler wave form on corona duplex. Our labs also insulate the subclavian arteries. Some labs measure blood pressures in the arm. You had a great case yesterday where we had a steal syndrome from a cabbage graph. So this is relevant and there are various criteria for subclavian stenosis, blood pressure gradients between the arms of 15 to 20 millimeters of mercury is common. There's one chinese group validated some PSV criteria as you can see there for the subclavian 343 centimeters per second for a greater than 70% lesion. Our lab we have loose criteria PSV about 2 50 or more importantly a doubling of velocity. Seeing post hypnotic turbulence, seeing plaque. Everybody's gonna get this right after Melinda Bender's talk, what is shown in this image, The mirror image artifact. This will definitely show up on your registry exams and that's and that plural area is a very common reflector. Briefly. The vertebral is we get a mid cervical snapshot in a healthy state. We should have a low resistive wave form similar to the I. C. A. With anti grade flow toward the brain and then we have a spectrum of abnormalities but there's some nice healthy normal vertebral arteries. In this case we have an A grade flow but it's a harvest hardy's waveform. So in addition to subclavian disease, a common place for vertebral diseases, the origin of that vertebral artery. This was a patient who actually had symptomatic vertebral basilar insufficiency, he had disease on the other vertebral. Excuse me as well. And you can see that vert origin lesion. This pattern we see is called the pre steel. You see mid systolic flow deceleration. Excuse me. And this is what we call the bunny rabbit sign and that's indicating early signs of steel in the setting of subclavian stenosis. Then we get that mid systolic flow reversal steel getting more prominent if you blew up a blood pressure cuff on the left arm or did exercise as dr Wong's patient did in the cath lab yesterday and repeated that you can get more steel. Here's a case where we have most of the flow is actually going in the reverse direction. A little bit of flow is going an A grade and then here we have retrograde flow and here's the left subclavian stenosis. And one thing I want to mention is a double check on your retrograde verts, they should be high resistive because the flow is going into the arm? Not the brain. Okay. I have a question here. I think what is the most likely diagnosis of this vert. Is it a normal vertebral artery, subclavian stenosis with vertebral steel stenosis of the vert more proximal to this segment or occlusion of the distal vert, anybody. You all know this this table here. What's the answer? Thank you. All right. So this is a high resistive vertebral artery waveform. It looks like that external carotid artery. And in about half of the cases this is because there's distal disease or and another half it's because of congenital anomalies and that vert is just not going into the circle of Willis. Last thing I want to mention again, know that content outline are incidental findings. So know your neck masses. So this is a beautiful image we actually published years ago. Uh you can see that image there. What is the most likely diagnosis here? Is this a carotid pseudo aneurysm? A thyroid mass. A carotid body tumor or a carotid jugular fistula. What do you guys think? I'm hearing different. I'm hearing different answers for this one. Um This one was really cool. This was a carotid pseudo aneurysm. Actually again published that case in vascular medicine. This was a traumatic carotid pseudo aneurysm. You can see there here's a carotid body tumor vascular arised soft tissue mass. Very vascular arised at the carotid bifurcation. It's called the goblet sign displays that uh bifurcation and it's filled with vascular arised wine on a angiogram? And of course we also have our thyroid nodules. So with that I think we're heading up to the T. C. D. Thank you very much.
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