Good evening. Thank you, everyone, for attending tonight's webinar, entitled, Surf's Up, a Comprehensive Spectral Doppler Review, a Good Summer Topic. My name's Lori Lazansky, and I'm the chairperson for the SVUE Learning Educational Committee. Before we begin, I have a couple of notes from the SVU office to share with you. So this webinar will be recorded, and it's going to be available online for attendees through the SVUE website at no charge. Please take a moment and get familiar with the GoToWebinar program we're using. Everybody should see a questions section along the side menu of your screen. It's near the bottom of the choices above the chat. So go ahead and type in any questions that come to mind during the presentation. And at the end of tonight's talk, we should have some time for discussion. To receive your CMEs for tonight's lecture, you need to wait for an email from the SVU office containing an evaluation. And you should expect that email in about seven days. When you get it, and you complete the evaluation, then your CME certificate will automatically pop up. Okay, so that concludes our announcement. And so let's begin. Tonight, we're honored to have Nicole Strissel. Nicole became interested in ultrasound when she was in high school after visiting her aunt who worked in ultrasound. And she's loved it for the past 25 years. Nicole went to school at the Mayo School of Health-Related Sciences for general and vascular ultrasound. After graduating, she was hired at Mayo Clinic Rochester and has been there ever since. Although she did do some vascular outreach at some of the smaller outlying Mayo clinics in her area until they grew enough to hire their own vascular sonographer. Nicole did different types of ultrasound for a couple years. And then she became a lead sonographer just concentrating in the vascular subspecialty and also became the technical director for her IEC-accredited lab. After 14 years, using her master's degree, she stepped into supervision. But she realized a few years later that she really missed scanning and working with patients. So to get back into clinical work, she accepted a newly-created vascular ultrasound research, innovation, and teaching position where now she trains all of the vascular medicine surgical fellows that come through her institution. She helps new hires go through Mayo's extensive vascular training process, as well as developing and participating in vascular ultrasound research. When Nicole is not working, she loves spending time with family, her dogs, and friends, either out fishing, walking, doing taekwondo, or creating some Minecraft worlds when it's too cold to go outside. And with that, please join me in welcoming Nicole Strissel. Thank you so much for that introduction, Lori. And thank you to Missy and yourself for getting me set up for this. Welcome, everybody. I can't thank you enough for giving up an hour of your evening to kind of hear me babble on here. I thought surf's up was really appropriate because we're going to talk about a lot of waveforms tonight. When doing vascular ultrasound for a long time, I think spectral Doppler is one of those things that we do on a daily basis and we don't hardly think about anymore. And I really want to drill back to thinking about it because it can be so helpful in the exams we do. So, I'm just going to dive right in and hopefully pull your attention for the next 55 minutes or so. Here's a couple of slides. Just I'll go over these in a little more depth coming up for our objectives. I don't have anything to disclose. And like she said, for your credits, Lori gave you that information. So, I'm going to talk a little bit about the objectives. I'm going to briefly go over duplex versus Doppler ultrasound. I'm also going to hopefully by the end of this, you'll be able to recognize or at least refamiliarize yourself with normal and abnormal spectral Doppler waveforms related to their different vascular beds. I would also like to review some of the pathology conditions and situations that really we get specific spectral Doppler waveforms for. So, like if you see that waveform, you know you have this pathologic process going on. I would also like to touch base on some of the pitfalls and hopefully give you a few of the tips not to fall into them related to spectral Doppler. And then if we have time at the end, I have four case studies, brief ones, because I know you'll have been listening to me drone on for a while to go over. So, that's what I hope to accomplish by the end of the night. Just as an FYI, I'm really not going to be covering the absence of arterial or venous waveforms. As most of you may know, if you find that, that really means that that vessel is occluded. Or with anything ultrasound related that my imaging parameters may be off. So, not going to cover any occlusions. I just briefly, whenever I get the chance to talk about anything Doppler related, I just want to briefly review duplex versus Doppler. The reason being is they are sometimes used interchangeably, but they're really not. So, let's just review those quickly. So, remember that Doppler is really those reflecting sound waves off a moving object. It's that sound you hear. Nothing else. Duplex, on the other hand, is when you're going to take our traditional ultrasound, which is when those sound waves bounce off the objects and create a picture that uses using their amplitude. Combine that with Doppler ultrasound. And Doppler ultrasound is the sound you're hearing. It uses frequency to determine that relative motion. Those two combined give you what's called a duplex image. If you ever have trouble or you haven't taken your RVT test or whatever, and you have trouble, remember, between Doppler and duplex, I kind of think of the houses out there and how a duplex has two houses put into one. That's the same for ultrasound. You need two pieces of an ultrasound to create a duplex image. A lot of machines have different things where they can not only take the duplex image, but have it update constantly. I know on a Sequoia, it's like the triplex. On GE, it's simultaneous. I'm sure all of them have their own little terminology for it. It can be really helpful when you are doing small vessels, but just remember that you tend to have more artifacts on your spectral Doppler waveform. I call it noise. You tend to have more noise when you have it running constantly. So for me, I tend not to have it on a lot unless I feel like I'm slipping out of a vessel. Okay, pinky promise, that's it for physics. I did physics a very long time ago, and I don't remember most of it. So that's all you're going to get in physics from me tonight. Okay, as we go through this talk, I really want you to ask yourself this on every spectral image. This is what I ask myself on a daily basis. It literally takes a split second now, but I realize I go through this process. Having been a fan of vascular ultrasound since I started ultrasound, and it's just, it's my modality. I love vascular ultrasound. What you want to ask yourself is, is this waveform normal for the vascular bed I'm imaging? If the answer is yes, then just go ahead and continue the exam. And on your next spectral image, ask yourself the same thing. If your answer is no, you have to kind of look at that waveform and figure out what's abnormal about it. Does the waveform tell you exactly what and where the problem is? A lot of the time it does, and we're going to cover that in this talk. If it doesn't or does, what additional images do you need to get as a sonographer to rule in or out the patient's issue? Ask yourself that on every spectral image. First, before we can talk about any pathology, we have to kind of know what normal is. So I've kind of broken this talk up into, we're going to talk about a lot of artery stuff, and then we're going to talk about some vein stuff. So we're going to start with normal arterial spectral waveforms. So for your normal peripheral arterial bed, this is going to be your arms and your legs. Your waveform should be high resistant. Now, remember that high resistant is when you have some flow on both sides of your baseline, which is this yellow line here. That's high resistant. Tends to be triphasic or biphasic, even though there's some controversy out there with the biphasic terminology. But triphasic would be, you can hear three beats, the first, the second, and the third. Also, in a normal peripheral arterial, you'll have minimal to no spectral broadening. And spectral broadening is seen in this, what we call this window here. If there's no gray, like if the black matches the black over here, you have no spectral broadening. If you start to see shades of gray in here, then you're starting to get some spectral broadening. You also will have no doubling of your peak systolic velocity from segment to segment. Now, that can vary as far as your facility. So whatever your criteria you use for peripheral artery, you know, continue to do that. Ours here is a doubling from segment to segment. You'll also have a nice upstroke. And by upstroke, I mean from the end diastolic up to the peak. It's a relatively low amount of time to get it up there. And you'll have no turbulence. Turbulence is kind of that peak of that waveform. Is it a pretty sharp peak, or do you have any sort of fuzziness at the top? For the visceral arterial bed, your waveforms are going to be a little bit different. So you want them to be low resistant. Now, remember, low resistant means there's forward flow throughout diastole. And you mainly are going to have all of your flow on one side of your baseline. There is an exception with this, and that's going to be your fasting SMA and IMA. So however your facility does it, you just want to ask the patient if they've eaten or drinking anything that morning, if you're doing a mesenteric artery. If they have, then the SMA and IMA may be low resistant because blood is wanting in that bowel to kind of digest that food. You will have minimal to moderate spectral broadening as a normal finding in the visceral arterial just because of the depth we have to image at. You know, most of these things, unfortunately, are really deep, right? Hard to see. We're not getting a good look. They're small arteries. We can't beam steer because we're using a curved or sector transducer. So it's kind of inevitable that we're going to have some spectral broadening. Peak systolics can vary, so really check the criteria for the artery that you're imaging. Here, we tend to use anything over 250 in the celiac and 275 in the SMA and IMA would be considered stenotic. That's a non-stented sort of situation. Stents kind of change those numbers. And then for the renal arteries, we tend to use anything over 200. I know there's the renal artery to aortic ratio out there. We don't tend to use that as much here. When you're talking about normal findings in the visceral arterial vessels, you have to just kind of briefly talk about the dicrotic notch. It's also called the dicrotic wave. You can use those interchangeably. And essentially, this is a notch. So when you have your upstroke and the artery is starting to turn and come back down, when the aortic valve closes, you get this transient increase in pressure, which creates this other upstroke. And that's where you form that dicrotic notch. Now, I find this notch incredibly helpful, especially when you're doing like some sort of thoracic abdominal endovascular aortic repair. And that surgeon has put like four branch stents to all the different vessels. So it looks like an octopus like coming out that you have to now try to figure out as it's buried in the bowel. If you sample each one of those with spectral Doppler, they tend to have the waveforms that you're used to seeing. So your SMA is going to be high resistant if your patient is fasting. Now, the celiac and the renals can look somewhat similar, but the renals usually have that dicrotic notch. So that can help you sort out when you have those really hard to see things. Now that we've reviewed normal arterial, we want to talk about abnormal arterial spectral waveforms and what components make them abnormal. The first one is spectral broadening. You've already heard me talk about it a little bit, but really this points to some turbulent flow, just meaning it's not laminar. So we have to kind of figure out why we're seeing that. One thing you want to look at is here we've got a nice no spectral broadening window. Here we have some shades of gray in there. So we're starting to get some minimal spectral broadening. Now, if you see in both pictures, there is a plaque burden. You could probably argue this might be a little bit more, but without transverse, you can't tell for sure. But what we can say is that even though these are pretty similar in peak systolic velocity, because of that spectral broadening, this lesion may be a little bit more significant than this one. Now, if you go down to the very bottom, I put this one in here. There's pretty much no doubt if you do any vascular ultrasound whatsoever that we have a stenotic lesion here. Mainly, you've got a huge speed, right, 500 centimeters per second. But what I did want to point out is sometimes you get spectral broadening purely because we didn't turn down our gain a little bit. So remember, if you can, without losing accurate information, try to decrease your pulse wave gain or your spectral gain to get rid of that make it black, because then if you know there's shades of gray under that window, you definitely have spectral broadening. Next is turbulence. Turbulence is really, I like to say it's that ratty sound you hear. You know, you can hear it almost before you see it on the spectral waveform. It's that non-smooth top. Now, turbulence is one of those things where it's not really normal, but it can be there for a lot of different reasons. The first one is tortuosity. You know, as that vessel bends, the laminar flow is really hard to get, especially when you're deep in a belly and a tiny artery. So tortuosity is one of the causes. It can be from a stenosis, and it can also be from an aneurysm or tatic area. It just means your flow is not laminar, and you just have to kind of try to figure out why that is. Next is tardus parvus, and this is one, if you see this, you know where the problem is. So tardus parvus, it's where you kind of get those rounded peaks because you've lost the upstroke. So that blood is trying to get through a stenosis, and you're downstream from that stenosis, and it's now lost its upstroke because it's taken so long to try to get through that narrowing. So when you see tardus parvus, you know that your problem is proximal to where you're sampling. And if you didn't find something looking proximal, you should probably go back up and see if there's a more proximal lesion. Now arrhythmias, I'm not gonna really talk a whole ton about arrhythmias, but they need to be in here because we do see them on our spectral waveforms. A lot of heart things go into arrhythmias. Again, I'm not gonna talk too much about it. The biggest thing I wanted to let you guys know is sometimes there's a rhythmic arrhythmia where like this top one, you kind of have this high peak, and then this little lower guy and a pause in the high peak, this little lower one, and there's probably gonna be a pause here. When you have a rhythmic arrhythmia, I would tend not to measure this one, but this one, because this will give you the worst case scenario knowing that this is how the patient's heart is pacing. This is what you're gonna deal with. If you have an arrhythmic arrhythmia, meaning it's not the same, this is not a turf for a terrific example. Imagine if you had like a sinus rhythm, and then a long pause, and then a huge beat, and then it went back into its normal rhythm. If you have that, don't measure the highest one. The highest one after that pause is where all that volume of blood was stored up, and it's always gonna be higher, and it's not accurately reflective of what the PSV is. So don't measure it if you have one of those kind of weird arrhythmias. So when you're talking about abnormal arteries, you always have to talk about those that aren't really going the right direction. So we're gonna first talk about this artery over here. This one's fully reversed, and this is in a patient who has a brachiocephalic fistula. We're distal to the fistula and sampling in the artery. So these are the patients who typically have what they call Steele syndrome in their hand, right? Their hand's really cold. Unfortunately, sometimes the fingers maybe have some ulcerations on them, or when they're having their dialysis, their hand is cramping really, really bad. So they come to us to figure out what's going on. For those, if you don't do hemodialysis access, what we're looking at is a brachial artery inflow here, and then right here, there's gonna be a connection to a main vein. What should happen is artery blood flow should come down, go into that main vein, as well as continue onto the hand. But we can see here that we are reversed. Now you say, okay, I get a reversed artery, but that artery looks really weird. Remember that that spectral artery or waveform is reflective of an artery that's hooked up to a vein. So you're gonna have some vein component in there, and that's why it looks really weird. So the VERT is one of those things where it's really like, that's the key to what we're looking at, right? Which direction is it going? So if you have a steel, a bidirectional, or a reversed artery, you need to check the subclavian artery. So here's an example of a nearly reversed artery. We still have a little bit of bidirectional flow on this top half here, but most of it's reversed. When you see that, there's a problem with the subclavian artery. Essentially, the subclavian artery should supply blood to that arm, but enough blood isn't getting down that arm. And so it starts to pull that blood from the VERT and make it go retrograde. That versus this one. So this one, you can see our peak systolic's pretty high. For here, anything over 140 is significant of a stenosis. You have a lot of spectral broadening down here. You kind of have this ratty look to the top of the waveform. So we have all the components of a stenosis. If you have a stenosis in a VERT, you don't have to look at the subclavian. Only when there's a problem with the direction of flow in that VERT. So to kind of point that out even more, if you see this little notch, remember we talked about that dichrotic notch, but sometimes you see it and you're like, I don't know if I should check this subclavian or not, because is this a pre-steel or is this just normal? What you need to do is go look at the other waveforms in that patient on that side. So if you look at the right IC and right ECA on the images off to your far right, you can see that there's the same notch. That means this patient has aortic regurgitation and it's not related to anything subclavian. Versus the images on the left, if you look at the VERT on the very bottom, you see that same notch. But when you go up to the ECA, which I find is the most reflective of that, you don't see a notch. And that's when you need to check the subclavian. And in this case, the patient had a significant stenosis down in that subclavian artery. Low resistant arteries. Remember in the peripheral system, you should not have low resistant. It should be high resistant arteries. Now, if you have a nice upstroke, but it's low resistant, well, what does that mean? That typically means there's a problem distal to where you're at. Like the foot is saying, I need that blood. Give me as much blood as you can. And so it's created a low resistant state so that there's forward flow throughout diastole. So it acts kind of like an organ, like it wants the blood all the time. Now, if you look at the PTA and DPA down low, you'll see that now they're tardus parvus, right? Now we know if they're tardus parvus, there's a problem proximal to where we're at. So what this basically tells us is that we pretty much have a problem in the calf arteries and a pretty significant problem. That's a pretty tardus parvus waveform. Now, I wasn't gonna talk about occlusions, and this is the only one that I have in there, but I had to put it in there to show you what we like to call the thump, the thump waveform. And this is essentially a waveform. And if you look at, you say, well, Nicole, you told me high resistant is normal and this is high resistant. It's got a good upstroke, so it's not tardus parvus. But if you look at the peak systolic velocity there, it's pretty low. And if you were to listen to the Doppler with this, it would really sound like a thump, thump, thump. That means the blood flow is coming up and hitting something. It's typically found when you have an acute arterial occlusion. Here, you've got a graft that's occluded. That blood is just like hitting a wall and stopping. That's what you're going to get. Below that level, you have this refill via collaterals. And I don't know, this is my own personal observation after like, you know, 20 years of doing this. If you get refill via a collateral, and there's a good collateral system, it's still Tardis Parvus. But if you notice some of these have like the peak is almost in the middle, it's not as rounded as that one we saw before. So when I have, it's kind of like a sharp tooth or like a saw looking waveform. When I see that I know that there's usually a pretty good collateral pathway for that blood to get down there because it's getting down there and the upstroke is starting to recover a little bit. So now that we've talked about normal and abnormal, let's talk about pathology. You know, there's certain conditions that we do see in vascular ultrasound where they have very specific spectral Doppler waveforms. The first one we're going to talk about is the pseudoaneurysm. Now, if you do any of these are typically after a poke, like a patient had emergent heart thing come up, and they had to get in there quickly, and they put the needle in, poke through and when they pulled it back out, blood remained along that track like the hole didn't close in the artery, then you get a little sac and you get blood flow into the sac. You have what's called a two fro waveform. This is flow that's coming into the sac and then exiting out that same track. The one other place that we do tend to see this two fro waveform is if you scan EVARs, so endovascular repairs, you can also see this when there's a leak, typically a type two leak. So when the lumbar or IMA area, you have blood flow back into the sac and then it comes back out that main artery, you can also get that two fro sort of flow. Essentially, it's anytime blood flows going into a sac and then coming out that same path. A couple things to remember with pseudoaneurysms, if you have a wider neck, those peak systolic tends to be a little bit lower and easier to see. As you can note in this waveform right here, we can really see the two fro pattern. If you have a really small neck like this one, you've got a really high peak systolic velocity, you can kind of say, well, it just looks high resistant. So what I do is I take this picture, but then I also take another one moving my spectral scale up to about 100, so that they can really see this fro part of the two fro waveform. If you're new to vascular, and you haven't scanned a lot of pseudoaneurysms, just a quick tip, the biggest thing you really want to do other than identifying it is measure the neck, as well as the length of the neck. And the reason being is a lot of times these are thrombin injected to get them to heal. So they'll stick a needle in here and put a clotting material in. And if you have a wide short neck, that clotting material is going to go right into your deep system, which is really unfortunate, really unfortunate. So sometimes if the neck isn't long enough, or it's too wide, they'll take them to surgery and just tie it down that way. The other condition that they get usually after a stick that's readily identifiable is your arteriovenous fistula. Now a lot of times they'll come to us and say rule out pseudo, rule out AVF. Even though the pseudo should have a bulge and the AVF should have a brewie if you hold a stethoscope against it, that's typically the indication we get. And they're very different. Pseudoaneurysm 2 fro arteriovenous fistula has a low resistant high peak systolic arterial flow. It's the one that's going to sound like a hurricane when you put it in there, right? You're going to get this kind of colored Doppler brewie stuff everywhere. You're going to put it in there and be searching around to try to find that type of waveform in the mess of all that flow. A couple things when you're dealing with AVFs that you can really help tell you like how big the AVF and where it may be connected to is sampling the main artery and the main vein that it's close to. So in this case, we sample our common femoral artery. This looks really normal to me. As we get closer down to that fistula, you notice you get a little bit more low resistant and it's kind of getting a little bit hard to determine what's what. Then you're right at the fistula itself right there. So you've got your low resistant high velocity. So then you want to check your outflow vein. So this is the femoral vein below, which looks pretty normal. This is it right at, which looks gosh knows what that looks like, right? Kind of vein and artery mixed together, high velocity again. And then above it, you get this pulsatile vein. So what this can tell me is that we have probably a definite connection to the common femoral vein because it's affecting the common femoral vein. But it does tell me we probably don't have a direct connection to the common femoral artery. It's probably a branch off the common femoral artery, maybe one of those circumflex arteries that got hit. Because if this was connected, if this fistula was connected to the common femoral artery, you would have a low resistant artery coming down to this because it would be going out that vein. So the connection is either a branch or a very small connection. And that can help them direct surgery. So important to know. Okay, not going to talk a whole lot about ECMO. Again, I do not claim to be an expert on this, but it's really important to know your spectral waveforms when you're dealing with this. So ECMO are those patients, really sick patients, they're always going to be in the hospital, you're always going to be going out portably to do them. And it's that extracorporeal membrane oxygenation. Basically, it's a way to either rest the heart and lungs or just the lungs. So the patient can try to recoup from whatever they're going through. The biggest thing is if you're asked to go up there and do any type of vascular ultrasound on patients who are on ECMO, you really need to know that this is a normal waveform. So when you get up there and you put your cursor down in the common femoral artery, SFA, whatever, you might get a flow that looks like a vein. And that's okay, that's normal. You might get one that's a little bit more pulsatile, although very odd looking. Again, that's a normal finding. So you really have to use your grayscale, your color to really help determine if there's a problem, because the spectral is not as helpful on patients who are on ECMO. Now, in the outpatient environment, you're going to run across people who may be on an LVAD. Now, and it can be an LVAD, RVAD, BiVAD. These are patients who they'll come in, they'll have a vest on, and they'll say, I can't take this vest off. And they literally can't. They'll have extra batteries on there, because all of this is hooked up to tubes that help their pump. Here, typically, they're patients who are waiting for heart transplant and they're trying to bridge them over to help their heart until they can get to a heart transplant. Again, I'm not going to go in depth with LVAD, that could be a whole talk on itself. But basically, you just need to know that these waveforms are normal when an LVAD is in place. So if you get in there, you don't want to go say, oh, my gosh, I've got a really low resistant tardus parvus artery going on. If the patient has an LVAD, that's what should be happening. Okay, now let's talk just briefly, there's just a couple artery waveforms where it's not abnormal, but it's not really normal either. And what do we do with those as sonographers, right? When you get one of those, kind of like this hedge, I just love this picture. It's like, it's not quite normal, not quite abnormal. I think it's pretty trim, you know, it appeals to my type A. Okay, so reverse arterial flow throughout diastole. What do we do with that? Flow throughout diastole is not normal, right? It should be high resistant in the peripheral system. But really, what's the significance of it? Every time I bring it up, radiologists just tends to ignore it. And when you think about it, you know, blood flow is going in. And then throughout diastole, it's getting pushed back the other way. And what I kind of like in that too, is, you know, there's resistance or hardening of the arteries probably below, because we often see this when there is arterial trouble, they've got a graft in, you know, they have native disease in their arteries, and it can't get back out. So it's just continuing to have that flow get pushed back the wrong way, instead of these really resilient arteries that kind of flap and go with the flow. The other one I want to talk about before moving on to veins is the spike off the top of the artery. So again, no one's really sure what causes this. We, you know, when I first started 25 years ago, they said, oh, it's artifact, never measure it. But then you realize it's not really artifact. It's move locations if you can, like within a few millimeters to still get what you want. But really, this is an actual part of the waveform. It just happens because there's not laminar flow. And I often see it in bulbous areas, you know, ectatic areas and not in an area of stenosis. So I would tend to measure the peak. And in this case, the snag for measured here, I would have tended to measure that one. And again, typically, this is not going to be in the stenosis range of peak systolic velocity. So you're okay to measure that top. But remember, if it's on every waveform, it's not artifact. It's just something is happening with that flow in there that makes it not laminar. And typically, it's bouncing all funny off different parts of the wall. Okay, we talked about arteries. Let's go on to veins. So let's talk about normal venous waveforms. What do we see in the peripheral vein? Typically, you're going to have that respiratory variation or phasicity. And then there's going to be changes with like distal augmentation or proximal compression or valsalva. You should have some adjustment as you go through there. Just a heads up, if you do venous insufficiencies at your facility, there is usually a normal valve closure. So if it's anything under a half a second, you don't have to measure that. Because blood is squeezed out, that valve needs a little bit of time to close and you see that on your spectral Doppler waveform. The visceral veins, well, those are a little bit more variable, right? You should see some phasicity, probably, depending on the size and depth, size of your patient and depth of the vessel you're looking at. You can see a little bit of pulsatility, but we can see so much variability. I did take a picture of a couple different renal veins. Both were read out as normal. Oftentimes, the report just specifies patent for any of our visceral veins. Let's talk a little bit about abnormal venous waveforms. These are some beta fish, just a little piece. I love these male betas. I have one at all times, not more than one. Okay, so what happens in your peripheral vein? You get pulsatility. Now, the first two slides and then that middle one is usually related to heart, something heart related. You get these super pulsatile veins. The ones on the right under the AVM, if you're at an institution where you scan malformations, the reason I put those there is just to remember to tell you that this pulsatility isn't related to heart. This is related to some connection with the artery. Now, unlike an AV fistula, which is one connection and is typically either an oops by a needle stick or it's created for hemodialysis access where you can get right in the fistula and get this low-resistant, high-velocity waveform, malformations are different. You'll just kind of get this subtly pulsatile vein because it is connected to an artery, but malformation, I remember it says many. AVM is many connections between the arteries and veins. They're often too small for us to see and they're not always going to have that or they don't actually typically have that high-resistant or, sorry, low-resistant, high-velocity flow. AVMs are a little bit more subtle. So the continuous flow vein, this was a really interesting case. All of these images are on the same patient, but a continuous flow vein is never really normal. Now, sometimes when you put it down, you have those people who chest breathe and just have them try to take in a bigger breath to kind of see if that changes phasicity and most often it does, but this was a patient who we did, okay, a valsalva on the right, you know, you can already see it's kind of continuous. The valsalva didn't work at all, went to the femoral vein, it was purely continuous, and then I went to the other side and saw a much more normal vein. So if you notice that there's a loss of phasicity and you get a very continuous flow vein, most likely you have some sort of obstruction proximal or or cephalad to where you were sampling. In this case, in that far right image, you can see there's a problem in the common femoral vein upper area, not sure that's the artery up on top, probably this little thing is a vein getting smushed down here, couldn't get any flow in there, and unfortunately this person had a large lipomyosarcoma involving with tumor thrombus into the external iliac vein, and so there was a totally blocked external iliac vein, and that's why your valsalva doesn't work, because there's no longer a connection between where you are taking your valsalva and up near the IVC where abdominal pressure can affect that. So we do need to talk a little bit about flow direction when we talk about abnormal veins, just always be aware of it, and with your spectral, your spectral should really match your color, right? So watch that invert button. A couple of times when you can get reverse flow direction that can really mess you up is reversed augmentation when you're doing perforator vein imaging in the venous insufficiency world. So most of the time when you squeeze, blood should go the normal direction, which is from superficial to deep, but what ends up happening is when you do that distal augmentation, flow goes from deep to superficial, which is a reversed augmentation. It can be really hard if you have reflux after that also, because it makes the vein look really funny, so just watch your reversed augmentation. The other time you can get flow direction problems is when you're doing a nutcracker case. So this is where that left renal vein crosses midline and is compressed between the SMA and aorta, and what happens is, is that left renal vein is so pinched sometimes that blood flow will flow retrograde back towards the left kidney and hit that gonadal vein. Remember the left gonadal vein drains into the left renal vein, so then flow will go down that gonadal vein instead of coming up and lead to pelvic congestion syndrome for a lot of people. The last one with flow direction, I have examples of pictures here for you, and this is a collateral pathway we do see fairly often when the innominate vein is out, and it can be missed really quickly because people just flip their color to blue in the IJ, take their sample, and don't realize that invert is on down in your, or the invert is not on kind of down here in your spectral waveform. So what happens is, is here we've got collarbone, axillary system is out here, draining towards, so this is all correct, it's draining towards the innominate. Here we're continuing to drain towards the innominate, and it should be right here. Put your spectral in there to make sure you don't see anything, and we don't see anything but artifact, but then if you see this is red right here, so what's happening is that left internal jugular vein is reversed. We tend to leave it red, we leave it on the upside like we would an artery to really draw attention to the radiologist that something's going wrong here. So just really watch your invert, that's like my biggest tip with flow direction. Venous stenosis. You know, vein stenosis is kind of less talked about, I would say, than arterial stenosis. Arterial is the doubling from segment to segment. We kind of loosely maybe use a tripling from segment to segment, so I have a couple of examples here. The first one is kind of a dubious one, right? It's barely a doubling, but it does change. I just wanted to remind people that when you're doing stents or any vein where you think there's a narrowing, you have to have that angle correct on to accurately measure your spectral waveform. So this one kind of doubles, and then it'll go back down to about 35, so kind of maybe something going on, maybe not sure. Here is a thoracic outlet study with a neutral waveform. You see how nice and big it is and how we've got this nice kind of phasic, slightly pulsatile, normal venous waveform. And then when the patient goes into a military stance where they roll their shoulders back and pushes their pecs out, you get this really continuous flow waveform that's, you know, way more than 20, way more than a tripling, and so you've got a definite narrowing there with that maneuver. In the bottom three there on the bottom right is an outflow vein stenosis, so you're coming in at 185, goes up to 544, and it goes down to 100, and I really want to point out those waveforms when you look at them. So that top one is fairly normal, right? This one is normal for a fistula. It's arterialized. It should be. It's not too ratty, you know, kind of a little bit turbulent, but not bad. Then when it's zipping through there, you lose a little bit of the turbulence, but you get a high velocity and a ton of spectral broadening. And then after you come out of there, you get just this massively turbulent waveform, which is usually abnormal, and if you saw this one and you didn't see anything proximal, personally, I would go back and check and make sure I didn't miss it. Okay, that's enough for venous kind of stuff. What I want to talk about now is artery and vein abnormal spectral doppler waveforms that are actually normal. So there are some circumstances where abnormal is normal, and these are my pooches for anybody who are dog lovers out there. These are my rescue pups from our local animal shelter. This back one is tater tot. This front one is cream puff, and I thought it was kind of good to pick here because, you know, they are both 50% French bulldog, but anybody can see that he was built a little different, has a little more pit, and she's got a little more old English. So those, other than my kids who I adore, these are my dog babies. Okay, so when is abnormal normal? When is low resistant in a peripheral bed normal? Within the first three months of a lower extremity arterial graft placement. So down below, you can kind of see here, this one is within that three months time frame. We still have forward flow throughout diastole, so we still have a low resistant waveform, but by the six month checkup, we now have a high resistant waveform. So the foot still needs blood, and it's wanted blood. Maybe it's healing an ulcer or something, and so it's going to be low resistant for that first three months. After that first three months, if it's still low resistant, something still isn't going quite right, so they have to look into it. The second area where it can be low resistant normal is your digital arteries. Remember, typically they're high resistant, but if a patient moves their fingers or they come and their fingers are really warm, then you will have a low resistant waveform, and that's totally normal. If you have a dialysis graft in the groin or arm, you will also have a low resistant spectral waveform above or proximal to that either graft, like arterial anastomosis or the AVF, and then immediately if you post-exercise somebody and look like if you're doing some like an endofibrosis study, right after they exercise, it will have some component of being low resistant. So here's an example of how those spectral waveforms can help us out when we're talking about our hemo access grafts. So I just said it's normal to have low resistant arteries proximal to the AVF in a working hemo axis. So if I put my transducer down, I was scanning upper extremity arteries, and my first question, if this was my first picture, I would ask that patient, do you have any sort of tilesis graft in your arm? If the answer is yes, then this is normal. If the answer is no, then this is not normal, and there's something going wrong downstream. Remember, nice upstroke, low resistance, your problem's going to be downstream from where you're working. Now, one of the things I love about spectral Doppler is you can tell so much by one waveform. So, our first image is usually our inflow artery, in this case, the brachial artery proximal to the AVF. I have a high resistant waveform that should never be high resistant. So, I can already tell you that I have a probable occlusion in that AVF outflow vein because it's no longer taking the blood, right? When you hook that vein up to the artery, that's how you get that low resistance, and there's a problem. So, when these two look alike, this is after the fistula, you can pretty much assure, even without looking, that you have an occluded fistula. That's what I love about it. You already kind of know what's going on. So, again, this is normal if there's an AVF present, and that's the arterialized vein. So, this is, again, an outflow of a hemo access. Veins should not be this pulsatile ever. If they did not have a fistula in place, I would be sure looking for one somewhere in abnormal connection because that would not be normal. Okay, you've hung in there now 40 minutes, guys. We're going to talk about a few of the pitfalls, and then we should have time to get through some of those case studies. So, let's talk about the oops, right? Okay, so I'm not trying to trick you with this picture, but assuming usually gets us in a little bit of trouble sometimes, right? That's what our moms always told us. So, here you've got your common iliac vein, and this is actually the common iliac vein. Now, I never trust purely a color, especially when we're horizontal and deep down in there. So, you always want to put a waveform in there, and so now I'm going to trust that that common iliac vein is occluded because I put a spectral in there, so I know for sure. So, then going down, the sonographer got this picture, and they said, oops, now we've got acute clot and occlusion of the external iliac vein. So, they showed the radiologist. The radiologist wasn't sure and said, hey, can we get a back scan? So, sure, no problem. Let's go on in there. So, looking at this, if you're a pretty advanced vascular sonographer, you have some experience, a couple things are going to catch your eye. The first one that catches my eye is that this is super horizontal, right? And it's hard. You're deep in the belly. You're using a curved transducer. You can't beam steer that. You have to try to rock, and there's all this bowel usually flying around in there. You know, it's a nightmare to try to get these deep external iliac and common iliac lower veins, but the other thing that catches my eye is this right here. So, we have an internal iliac vein. Now, I notice a couple things. One, it's not going the right direction, right? An internal iliac vein should drain up into the external confluence and then drain out that common iliac vein, but we know the common iliac vein is out. So, this would be a retrograde internal iliac vein acting as collateral, but where is that flow coming from? There's only really a couple places it could come from. One would be collaterals, which is, you know, usually you would see them somewhere in here, and I'll tell you there wasn't in this case, or it's the external iliac vein. So, I kind of went in there, adjusted a few things. I said, first, you have to put that spectral in there. Spectral Doppler has such a small focused power. It's so much more sensitive than color. Like color, you're asking that pore machine to try to fill this whole thing and send power everywhere, whereas spectral, you're saying, hey, I want you to see if there's any motion flowing through here. So, always, always, always put that spectral in there before you go into the radiologist and say, oh, I don't think this is open. Slap a spectral in there and see what you get. So, I'm like, okay, I know we have some sort of flow in there. Now, I just got to prove it with color. So, I was able to finally get it, but it was a ton of work to get it with the color. So, spectral can really be our friend. Okay, different shades of gray. This can happen throughout the body. I see it most kind of in the abdominal mesenteric area, as well as on our incomes. So, I just grabbed one of the incomes to kind of review this with you guys. Shades of gray really do matter. You don't want to measure artifact on your venous exam. So, if you see how white this augment is over here and how kind of a charcoal-y gray this is over here, they're probably not the same vessel. So, when I get this, where they're a different shade of gray, I go look in the general area, kind of wherever along my spectral line is, and I say, hmm, is there something else in this area that's significantly refluxed? And lo and behold, in this patient was the SPJ. And you can kind of look here. This is, you know, maybe around, I don't know, 14, guys, right? And if you look over here, I don't know if this reflects well, but there's this subtle line back here. That's right about 14. So, in this case, the patient did not have popliteal vein incompetence. They just had significant SPJ incompetence. And that's the difference between a patient having DVI, which is highly untreatable, right? There's just not great things for it. And the small saphenous, which they can go in and ablate and take care of for the patient. So, it makes a big difference. Now, I'm not going to talk too much on this one, but discrepant waveforms are a thing, right? If you're in one vessel and you're getting two different waveforms, you really need to go make sure that, A, you're in the same vessel and understand, if you can, what's happening in between. Now, that's a really hard scan, right? It doesn't really look all that pretty. But you have this really high resistant vert artery, which looks like here's vein, here's your transverse processes. Yep, I believe that's vert. And then down approximately, you kind of have this other thing where I'm not sure it's the vert, right? A lot of things can come off down there. You got your thyroidals and all that sort of thing. You have a really normal looking vert. So, if this is the vert, there's a problem in between here somewhere. We did have a CTA of the neck to refer to. And actually, this was one of the thyroidal arteries. And this was occluded down approximately and being refilled via collaterals, which makes a little bit more sense. So, just the big thing is, if there's a discrepancy from one segment of a vessel to the next one, go try to figure out in between, if you can, what's going on. Okay. So, next is scale. If you're like really adjusting your color to try to get your color, don't have your spectral scale so high. So, in this case, we're trying to show like an occluded SFA. And I believe it's occluded, right? We're getting vein flow in the color. So, you know, that's pretty low and we're not seeing anything. But don't have your scale at 150 on your spectral. Don't have your scale at 150 on your spectral. Try to pull it down to like 50 or less, because you're looking for very minimal flow. If there is any flow in there, it's going to be, you know, 10 centimeters per second or less. And you need to adjust your scale accordingly. That also goes, if you have a high grade stenosis, like say in the mesenteric arteries, you don't want your scale set at 100, because the end diastolic might be above 100. And you're going to totally miss any big waveform that's going to be above that. So, just remember to set your scale according to what you're thinking you're going to find in there. Which one of these is right? So, I hate when these renal arteries have such pulsatile veins. I mean, they can be so pulsatile. You can't figure out which is which. And you can see this isn't a pretty scan. It's hard to get. You're trying to get something in there. You have patients probably breathing. They can't hold their breath. You're about at the end of your rope. But if you said that this one was the artery, you would be correct. This is a very, very, very pulsatile vein through there. And this one is not. The thing I tell people to look for is, do you see that lovely little thing we talked about at the beginning for normal visceral? The dicrotic notch. You know, even your segmentals will have a component of that. So, I try, try, try, try to see that. You can see here we got an upstroke with no dicrotic notch. So, this is purely the vein. Wall filter, again, segmental arteries or if like you're down in the foot DPA, PTA, and you're really trying to get that flow, you really need to lower your wall filter. This is spectral. And so, this can be the difference between like a 0.9 or maybe a 0.79 in your RI, which is the difference between kind of borderline or really high RIs. So, lower that filter so that you can see this. The machine is trying to help you by getting rid of artifact, right? But sometimes when it comes to wall filter, it gets rid of really useful information. So, if you have your spectral and you see like this, your black line, you know, seems to cut, your wall filter is set too high. And that's something you can preset on your machine or your rep should be able to do that with you. If you find that all of your spectrals have a pretty significant black line down there, just have them reset your wall filter. Okay. Artifactual spray. Again, you know, we're going to talk a little bit about shades of gray, too, in this. So, white, right? And we've got this kind of double waveform. Everybody's like, well, what do we measure? You always measure the biggest one, right? Well, usually, except for the bright white, is typically what your sample gate is in. So, this needs to be turned down. So, this was the same patient with a turned down gain. And you can see we're at 65 and 85. And this one, if you look here and kind of drew this over, you're going to be close to kind of that 70, 80 mark. So, this was probably the larger anominate vein or something else right along this whole spectral line that we were picking up. So, turn down your gain to get rid of all of that kind of artifact that you don't need. Talk very briefly on Doppler angle. Remember, a big thing, if you are trying to diagnose a venous stenosis in particular, like everybody knows, turn your angle correct on when you're doing arteries. But when you're doing veins, if you are doing a hemodialysis fistula graft throughout that central outflow vein, iliac veins for May-Therner, stented veins, or if you think there's a stenotic thoracic outlet maneuvered vein, you need to have your angle correct on there. That's really the only way to accurately measure it. So, here was the hemodialysis access. They forgot to put their spectral on. The machines are relatively good, but we can't tell you for sure that's accurate. And you know, a lot of us who do a lot of vascular are very type A. So, pop that cursor on there, even in the vein. Here, you can see we've got a stent. So, we should have an angle correct so we can measure that, especially because here in the common femoral vein, it's still stented. And this one looks kind of not so nice, right? Like this one looks like it's going to be low, but this one looks like there could be a stenosis. So, it's really, really important so that we can get an accurate peak systolic. Again, I'm not going to talk hugely about angles. I know some facilities tell you to use 60 or 0 at all times when you're in your arteries, and you need to follow that. But just know that anytime you're above 50, you can get grossly kind of elevated numbers. Whenever we're in the peripheral system using a 9L transducer, like the linear transducer, we try to stay at 50 or less because that's where it's proven to be the most accurate. Closer to 0 is always the most accurate. So, here is just a quick representation. This is at a 45 degree angle. This is at a 60, and you get almost 100 centimeters per second difference. Now, this one is all still above that criteria of 230 for a severe stenosis in the ICA, but sometimes it can make a significant difference, a surgical difference, which varies for the patient. Okay, so frequency, guys. So, don't forget that your pulse wave also has a frequency. This is a 9L transducer, and really down here, you know, sometimes it's aliasing over, and you're like, oh, dang it. I can't get anything. I need a little bit more. Sometimes, bring your frequency down as far as you can or switch to a deeper transducer that can allow you a little bit more scale. So, here is the same patient, just a slight angle change, but a big frequency adjustment. So, here in the bottom left, it's aliasing over, and we can't accurately measure it. So, we dropped the frequency. Usually, this is a GE, but it's usually related, you know, you should be able to see that on your screen for whatever machine you use. Dropped it down to a 3.1. We were easily able to get that. It can also help you, like, if you're vert, if you're like, I can't hardly see the vert. If you lower your frequency, it can give it a little more oomph, so you can see your waveform even better. So, don't forget about pulse wave frequency. Okay, just to review, you know, I think everybody knows what normal and abnormal are, but if you don't remember anything else from the talk, try to remember this because it's going to help you out. When you have a tardus parvus waveform, wherever you're at, there's a more proximal stenosis. If you have that high-resistant thump, you're possibly more, you have a distal occlusion. Too-fro flow will be your pseudoaneurysm or your usually type 2 leaks in an EVAR. You're very low-resistant, high peak systolic artery, you'll typically be dealing with some sort of fistula somewhere. And then continuous venous flow, possible upstream stenosis or obstruction of some kind. Okay, let's see. I think I have time. I'm kind of trying to time myself. Sorry, guys. So, I think I've got time. I'm going to go through these fairly quickly, so we have time for a little discussion, then you can have your evening back. But let's go over just, I have four case studies. I'm just going to run through them quickly. So, case study number one was a 39-year-old male. He presented to the ED with sudden acute onset of severe pain from the top of his chest up to his neck. He didn't have any other significant complaints or issues or labs, and the indication for us was to rule out dissection. So, I'm just going to give you like literally five seconds to look at this picture and just kind of generate some thoughts on everything you know, what you're looking for, right? So, are those normal arterial waveforms for a 39-year-old? And I'm going to go back to that picture in just a minute. Are they normal? He has no history of any arterial trouble. If they're not, which I hope you said they're not because they're not, can you put a qualitative turn on the type? You know, are you dealing with turbulence or spectral broadening or tardus parvus or all three? And if you are dealing with something like that, does it tell you where the issue may be? So, here they are again. So, you need to look at these. It's got a relatively good upstroke. So, it means that there probably isn't a significant stenosis above, but it's really not a normal upstroke either, right, for a peripheral system. So, there's probably some sort of obstruction up top. It's just not like impeding a ton of blood flow getting down there. You can also look and there's low resistance. Shouldn't be low resistance. So, that means there's problem. The leg is wanting blood from something. So, maybe a more distal issue or maybe it's just like, oh my goodness, I all of a sudden can't get blood, right? So, there's some ischemia developing down there. So, this patient had a type A aortic dissection from the aortic root all the way to the iliacs. So, this is a really severe condition. Typically happens in somebody who's a little bit older, but type A is the most dangerous because it starts up in that ascending aorta. The really interesting thing that was, other than pain in his neck, this patient really didn't have any symptoms. Usually, they're fainting, they're short of breath, they stroke-like symptoms, leg pain paralysis. I mean, these guys are usually in dire straits, but he was actually symptomatically pretty okay. The patient did go on to have an aortic root replacement. He had a mechanical valve conduit. They did replace the ascending aorta with a graft and they repaired the innominate artery with the interposition graft. And he was recently discharged and is really doing well, which is good. This could be a killer. Okay. Case two, 51-year-old male presented the ED with indication of no palpable pulses, arterial occlusion, venous versus insufficiency. Is this normal or abnormal? Why? And do you notice anything else? Let me give you like five seconds to kind of look at that. Okay. So first things first, it's not normal, right? What's wrong with it? Well, it's low resistant. Okay. So if it's low resistant, where's the issue? It's distal to where we are, right? It's that ischemic issue. Now, if some of you, if you've done a lot of vascular, you may also notice that not only is it low resistant, but there's this kind of tilt, right? It's kind of tilting like a tree in the wind a little bit. It's not tardus parvis, but it's leaning, leaning, leaning tower pisa, right? That's what's happening. And so that means the upstroke isn't entirely normal either, which means we probably have some sort of proximal stenosis, but it's probably not too severe. So something distal, something proximal. And if that's what you were saying, you're absolutely correct. There was just a mild iliac artery stenosis causing that lean, and then multiple mild to moderate stenosis in the downstream vessels. Number three, this 82 year old female, she was transferred from a nursing home because they couldn't wake her up. Prior to not being able to wake her up, she had complained of dry mouth and had a recent history of her retal stents placed for stone. So they thought she was in urosepsis. Two days after she came in, there was some concern because she had some decreased pulses in her lower extremity. So this is what her left common femoral artery looked like. Normal or not normal? If you said normal, I would have said normal too. It's not that bad for 83 year old. So here's some more images. Ask yourself again, normal or not normal? Okay, not normal. So we've got a normal-ish common femoral artery, right? Now that we've seen this, we'll add the ish, right? I would have said it was just normal. And we have very abnormal proximal profunda and SFA. So where's the problem? Remember, if you get different discrepant waveforms in the same artery, you need to look between where you got those waveforms. So that problem should probably be somewhere in the common femoral artery below where we initially sampled, but above that bifurcation. If it is, what is the problem? Well, now there's distal ischemia. So we probably have some sort of stenosis or occlusion. So this patient, they did go on and find acute occlusion, focal occlusion of the common femoral artery, kind of right near that SFA proximal. So it's kind of what you get, right? Last but not least, and kid you not guys, last couple minutes here. This was a 93 year old male. He presented to the ED with unstable angina. They did order a lower extremity ultrasound for some concern for DVT. So when you look at this, what are your thoughts? Here's the left side. So this is nice, you know, pulsatile. He's probably got some right high sided heart failure, right? He's like 83. Nicely valsalva. So I'm going to go back to this one real quick, because I want to point out one very important thing. If you said this is continuous and doesn't look real good, you're absolutely correct. There's probably something, remember, cephalad to where we are sampling. The one thing I want to point out with that was different than the other iliac kind of vein case I showed you is that this one has a good valsalva. What that tells me is that there is probably a pretty good open vein between where I'm sampling and the IVC, whereas the other one, it didn't valsalva, which tells me is probably occlusive. So whatever's going on here, I don't think it's occlusive. I think it's open. And so this really points, this picture right here points to an extrinsic compression. And that's exactly what we found was unfortunately a large mass in the groin. I didn't snap the picture guys, but there's or I didn't put it in here, but there's a very thready external iliac vein underneath here. So it is open. It's just being pushed on. Thank you guys so much. That's the end. I'm going to stop chattering at you. I hope that you got something out of this.

spectral Doppler ultrasound

arterial waveforms

venous waveforms

normal waveforms

abnormal waveforms

arterial dissection

stenosis

fistulas

Doppler angle

frequency adjustments