Comprehensive Echocardiography Guidelines Overview

Hello, everyone. I am Christina LaFuria, the Director of Education at ASE, and I'd like to welcome you to ASE's Guideline Webinar Series. Today's webinar is titled Guidelines for Performing a Comprehensive Transthoracic Echocardiographic Examination in Adults, Instrumentation, and Nomenclature. This is Part 1 of a Part 2 series, and we'll talk a little bit more about Part 2 later on. So without any further delay, let me introduce today's speaker. Dr. Carol Mitchell is an assistant professor in the Department of Medicine at the University of Wisconsin-Madison School of Medicine and Public Health. She currently teaches an introduction to vascular ultrasound course to the cardiovascular fellows and instructs teaching labs for graduate student courses in the Department of Medical Physics. She's previously been a program director for diagnostic medical sonography programs, served as chair. for the Joint Review Committee on Education in Diagnostic Medical Sonography. She's a commissioner of the Commission on Accreditation of Allied Health Education Programs, is a member of the Cardiovascular Credentialing International Advanced Cardiac Sonographer Credentialing Exam Committee, served on numerous committees of the American Society of Echocardiography, and is currently serving on the American Board of ASC's Board of Directors in the role of treasurer. It is my pleasure to turn the webinar over to Dr. Carol Mitchell. Thank you so much. Thank you for the opportunity to present part one of this two-part webinar. Today's lecture will focus on nomenclature and instrumentation as it relates to the ASC guidelines for the performance of the comprehensive transthoracic echocardiogram in adult patients. I'd like to begin with some acknowledgments, and I would like to thank and recognize the members of the writing group and the expert sonographers that also contributed to images for this webinar and the content for the guidelines. I'd also like to thank the ASB members of the Guidelines and Standards Committee and Board of Directors for their very thorough review and, again, providing expertise and guidance into the development of this guideline and this webinar today. Our learning objectives for today will be to describe the... scanning maneuvers of tilting, rotating, sliding, rocking, and angling, and how they are used to optimize image acquisition. We will also state how the following instrumentation controls affect an ultrasound image to include discussion on grayscale map, dynamic range, overall gain, and time gain compensation. We'll also describe why optimizing the color Doppler scale setting is important to evaluate low flow states and how the setting may influence the appearance of regurgitant jets. We'll also describe how the spectral Doppler settings can be optimized for performing Doppler tissue imaging, and we'll list the advantages and limitations of pulse wave and continuous wave spectral Doppler. We'll begin with discussion of the scanning planes, image acquisition windows, and scanning maneuvers. So, to review the scanning planes that we'll be talking about, we'll be looking at the long axis. where we acquire our parasternal long axis images, and that's along the long axis of the heart from the apex to the great vessel. We'll talk about the short axis plane, which is a cross-section of the left ventricle demonstrated here, and this is how we image the heart in a series of axial planes. And then we'll talk about the apical plane, where we see the apical four-chamber view. The scanning movers we'll begin discussing are tilting, rotating, sliding, rocking, and angling. The tilting maneuver is done by maintaining kind of a fixed base on the transducer on the heart, and then we're going to tilt anterior and posterior to see our different imaging planes. An example of this is diagrammed here in our schematic drawing showing we're imaging from the apical window, and our first imaging plane is very posterior where we see the coronary sinus. Then as we tilt anterior, we would come into the four-chamber view. then into the LVOT and aortic valve and ascending aorta or the five-chamber view. And then in some adults and routinely in P's, we're able to continue imaging anterior and see the right ventricular outflow tract, pulmonic valve, and main pulmonary artery. This video clip starts really at about section three of our somatic drawing. We're starting by imaging the apical four-chamber view. And then as we tilt anterior. We'll come into the view where we see the LVOT, aortic valve, and ascending aorta. And then as we continue to tilt anterior, we'll see the RVOT. the pulmonic valve, and the main pulmonary artery. The next maneuver we'll discuss is rotating. And this view or maneuver is done routinely when we rotate from a long axis view to a parasternal short axis view. The movement of the transducer is we keep the transducer in the same location and we just change the orientation index. So here we've rotated 90 degrees to move from a parasternal long axis view to the short axis. view. And that's what our diagram is showing here. Again, we're longitudinal. The orientation index is aligned towards the patient's right shoulder. We're going to rotate at 90 degrees. And then what we would do when we're imaging is you would kind of slide your transducer so you're directly over the aortic valve, then rotate it 90 degrees. And then we would rotate into a view where we're now at short axis on the aortic valve. And this would start our parasternal short axis. fuse at the level of the great vessel, and then we can utilize a maneuver called sliding. And what this is, is this is where we're going to physically move the transducer. This is typically done in the short axis plane when we need to move in between intercostal spaces to stay perpendicular to the anatomy of interest at each level in our short axis fuse. So an example of this would be starting at the level of the great vessels where we see the aortic valve, and then in order to say kind of on axis, we would need to physically slide the transducer lower on the body to then demonstrate the apical area. The next maneuver we'll discuss is rocking. Rocking is a small maneuver that is used to center a structure. And so this is routinely done when you're imaging in the parasternal long axis view. And we're starting with our nice long axis view showing the left ventricle. we want to bring the LVOT and the aortic valve slightly more horizontal. What we can do is rock towards the index marker that we're showing here, rocking away and then rocking towards the index marker. And in doing so, what we can do is bring this LVOT and aortic valve more horizontal and more perpendicular. So it will allow for an easier and more accurate measurement of the LVOT and aortic annulus. And then we can zoom on that view and also maintain a nice perpendicular orientation to our structure of interest. Next, we'll talk about angling. And what angling is, is it's a small maneuver that's done. Instead of trying to center a structure, we use angling to direct the sound beam towards our structure of interest. So in this example, what we're showing with the motion of the transducer is we're angling rightward on the heart to demonstrate and focus in on the tricuspid valve. And what that would look like during our echocardiogram examination is this view here, where we see the right atrium, the tricuspid valve, and then angling more leftward in position, we can focus in on the pulmonic valve. And here we see the RVOT, the pulmonic valve, and the main pulmonary artery. So this is an example of the scanning maneuver angling. We'll next review our image acquisition windows, and we'll start by looking at the parasternal views. These are often, as long as the heart is levocardia, the apex pointed towards the left, we'll obtain our parasternal long axis and parasternal short axis views from this window. The apical window is where we'll do our series starting with the apical floor chamber view and then moving through the apical views. The subcostal window, our starting view will be the four-chamber view. The right parasternal window in adults is predominantly used to locate the ascending aorta and then to identify kind of our angle of incidence replacement of the PEDOS transducer to get our most accurate Doppler measurements, like in cases of aortic stenosis. And then the suprasternal notch view, which is used for imaging of the aortic arch. So just to review kind of our starting positions for acquiring these images. In the parasternal window, we'll start with the patient in the left lateral decubitus position. The index marker is towards the patient's right shoulder. And our starting view is going to be the parasternal long axis view, which we see here. The left atrium, the mitral valve, left ventricle, LVOT, aortic valve, ascending aorta comes this way, and the right ventricle. The next... window is going to be the apical window and patient is again in the left lateral decubitus position. It's best if you have a cutout bed so that you can get the proper orientation to the apex. without having to reach so much as a sonographer. The index marker is going to be pointed towards the 4 or 5 o'clock position, and the starting view is going to be our apical floor chamber view. And often you'll find the best window under the breast tissue and ceiling for the apical impulse. And this is our starting view then, the apical floor chamber view, where, again, we'll see the left atrium, left ventricle, right atrium, right ventricle. Then we'll move to our next... position, which is the subcostal view. For this view, the patient is rolled into a supine position. The index marker is pointed towards the patient's left side at the three o'clock position. And the starting view is going to be our subcostal four chamber view. And what we see here is going to be the left atrium, the micro valve, the left ventricle, right atrium, tricuspid valve, right ventricle. Now, some tips for getting this image are oftentimes when we roll the patient, their legs will be extra. extended. And if you notice when you're pushing on the abdomen to angle up under the xiphoid to get this view, if the patient is kind of tensing against you, oftentimes if you just have them bend their knees up, that will relax the abdominal muscles and it may make getting the view a little easier. Another tip would be to slide a little more rightward and use a little more of the liver as your window for being able to get this view. Next is the right parasternal image acquisition window. And for this window, we're going to roll the patient into a right lateral decubitus position, extend the right arm above the head. The index marker is going to be towards the patient's right shoulder. And what you're trying to do is image in a plane that you're going to see the ascending aorta coming directly out of the heart. And we're trying to align nice and parallel for it for a good Doppler angle. The starting view is going to be looking for the ascending aorta. And again, in adults, this is predominantly used for locating the ascending aorta and then placement of the PDOS transducer. So what that's going to look like is this is the ascending aorta coming up and out of the heart. And then we can take a Doppler while we're imaging it. But again, also, this is a good way to identify the ascending aorta for placement of the blind continuous wave Doppler transducer. Next is the suprasternal notch image acquisition window. Again, the patient's going to be in a supine position. The index marker is going to be towards the patient's left shoulder, and you may have to do small rotations between kind of a 12 o'clock and 1 o'clock position. And the starting view is going to be long axis of the aortic arch. Now, if you start with your probe too perpendicular, you're going to have difficulty getting this arch stretched out. So one of the things that we tell our... students to do is if you can tip the face of the transducer inferiorly so that you are aligning almost parallel to the neck, you may have better luck stretching out the ascending aorta, transverse arch, and then the descending aorta. Next, we'll talk about 2D B-mode instrumentation settings, and we'll be discussing grade scale maps, dynamic range, overall gain, and time gain compensation. So, we'll start with discussing grade scale maps. And this is an instrumentation setting that adjusts how the shades of gray will be displayed on the image. So it's not adjusting the number of the shades of gray. It's adjusting how bright you're going to assign each amplitude of the signal that's returning to the ultrasound system. So the effect that it's going to have on the image is it determines how the shades of gray will be displayed. And the operator can select based on specific findings of the image. And in the olden days, we used to be able to bring up something called our post-project. processing curve and you see kind of a gamma curve. And what we're looking at here is we have our gray scale bar and it would kind of tell us how our range is being displayed of our brightness. And this is just a linear map. So it's kind of showing an equal brightness assigned to the blacks and whites. Other post-processing curves may look different and we can kind of choose how we want to enhance and suppress signals. So this is an example of on one ultrasound system just using grayscale map F compared to grayscale map A. On this system, map A is the most linear of the grayscale maps, so this is a more equal representation. But depending on your lab, what you want to make sure is that you have a preset selected that's going to give you the best definition of your endocardial tissue borders and also help you discern your compact and non-compact myocardium. to make the most accurate measurement. B-mode colorization is another tool that we can use. What this does is it transforms the grayscale image to a different range of colors and this is really based on lab preference. It may demonstrate certain pathologies better, and there are certain interpreting physicians who may like you to use a certain colorization because it helps them see certain pathologies better. The effect that it has on the grayscale image is that essentially it's just colorizing the map that you have to a different set of colors. So this is sepia in this case. It does not change the amount or the type of information displayed, only the perception for the viewer. And this is just looking at this real-time, again, map eye in the grayscale, and then colorizing that to sepia, but we're still using the map eye. Next, we'll talk about dynamic range. And this is the ratio between the highest and lowest received echo amplitudes in the image. By adjusting this setting, it adjusts the appearance of the shades of gray on the image. So a low dynamic range setting yields an image that is very black and white. very high contrast as seen here with a dynamic range of 50 decibels compared to a dynamic range of 75 decibels. A high dynamic range setting produces an image that has more shades of gray as seen here. And the reason why is it has a smaller range of amplitudes that's assigned to a particular shade of gray making up the image. So if we have more shades of gray, we can kind of disperse those amplitudes differently. And in cardiac imaging, we want to provide enough shades of gray to discern the interface between the compacted and non-compacted myocardium. And if we look at this in real time, most systems that report dynamic range in decibels will have a range between 70 and 75 decibels for cardiac imaging. When you're looking at a dynamic range of 50 decibels on this system, what you can see is this is a much more black and white image. We lose detail regarding the myocardium. here and it's harder to discern our borders for accurate measurement. So in summary, while grayscale maps and dynamic range appear to do similar things to your image as to how the grays are displayed, they are actually doing different things. With the grayscale maps, they're going to adjust the brightness level for each shade of gray. What dynamic range instrumentation does is it determines the number of grays. scale values or the number of gray shades to be displayed. Next, we'll talk about overall gain. And by definition, this is an instrumentation control that adjusts the brightness of the image and it does it equally throughout the entire sector. So the effect that it has on your image is the overall brightness. And the gain should be set just high enough so that there are just a few echoes demonstrated in the blood and the blood endocardial tissue borders are well delineated. So this is an appropriately gained image at 4 decibels, and this would be an undergained image. And again, you see the loss of detail as being able really to discern our blood endocardial tissue quarters. This is looking at the clips in real time. So again, appropriately gained image and an undergained image. Next, we'll talk about time gain compensation. And this is usually represented as a series of pods that can be adjusted in a... certain area to amplify a particular portion of the image. Usually it's a curve like this because the deeper the sound travels in the body, the more attenuation. And so what we're doing is we're doing selective amplification so we have an evenly bright image. And what we see here is we're selecting our pods to optimize our image so we have an equal brightness throughout the image. And then this is an example of inappropriate image. that TGC pods. And what you can see is that we've completely suppressed the amplification of the echoes in these regions. And how that affects the image, or you see these focal bands across these areas. And if we look at this image in real time, again, this is the same patient here and here, just with appropriately set time gain compensation controls here. And again, the appearance of the focal banding when the TGC is not set correctly. There is a feature on most ultrasound systems now that's called an automatic ultrasound optimization feature. It has different names based on the vendor. But what it does is it's a function that allows you to rapidly and automatically adjust the TGC. So from the image before where our pods were set inappropriately, we can hit this automatic ultrasound optimization feature, and it gives us a quick correction to the image. So it selectively amplifies the echoes. that are returning based on the appearance of structures across the image. And it is considered a time-saving feature, particularly if maybe you're doing a bedside and you're having to do lots of preaching because you can't get your system as close as you would like to. It may be a feature that helps you. Having said that, oftentimes there is still opportunity for some manual adjustment to fully optimize the image. But this is a good, quick starting point. This is showing, again, just use on the same image that we showed with the TGC set wrong before using the automatic ultrasound optimization feature. Then the sonographer manually also did a few tweaks to the DGC after using the auto-optimization feature. Next, we'll talk about frame rates. High frame rates are important in echocardiography because we want to maximize our temporal resolution. The heart is a feeding structure, so our higher frame rates are going to show the real-time motion better. Things that you can do to increase frame rate are decrease the depth of your imaging, decrease the sector size, decrease the number of focal zones, and reduce the number of scan lines being written per sector sweep. And this is an example of how these tools affect frame rate. So this is a depth of 170 millimeters. These three image clips are all taken from the same patient. And then this is with a narrow sector width, and you can see our frame rate is at 84 Hz. This is increasing the depth to 240 mm. The sector width is still narrow, but our frame rate has dropped to 73 Hz. And then if we increase the depth to 240 mm and open our sector width as wide as it will go, our frame rate drops to 43 Hz. And if you just concentrate on looking at this image compared to this image, What you can see is that this one has a much lower frame rate. The temporal resolution is much poorer. And again, it can be optimized by decreasing the depth and narrowing our sector width. Next, we'll talk about color Doppler imaging instrumentation settings. And we'll be discussing the region of interest, the color Doppler velocity scale, color gain, velocity scale, and how you can optimize it for laminar versus turbulent flow. when you might want to use higher and lower settings. So we'll talk first of all about our region of interest. And this is an instrumentation setting that defines the size and position of the region of the color interrogation within your B-mode image. And we typically call this the color box. And what we're looking at is how the size of this affects your frame rate. Setting that region of interest as narrow and as shallow as possible allows for maximum frame rate. and velocity scale. And so it yields the best temporal and flow velocity resolution. And just looking at these in real time, again, this is our narrow sector, and we have a frame rate of 35.6 frames per second. When we open that up wider, what you can see is blurring of the color, poor temporal resolution, and our frame rate drops to 14.9 frames per second. So again, the tighter you can make this... The shallower you can place it by adjusting depth, the faster your frame rate is going to be. Next, we'll talk about the color Doppler gain feature. And this is an instrumentation setting that's used to demonstrate optimum color fill and anatomic structures. And the way that you optimize this is you start by turning your color gain all the way up until you see speckles just outside your area of interest. And then you slowly turn it down until you have fill within the structure of interest. and no more speckling outside of that. And the effect that the color gain has on the image is that it amplifies the color Doppler signal to demonstrate color flow in these anatomic structures. And if we look at this real time, this is imaging of the pulmonary vein, and this is a color flow Doppler gain setting at minus 17 decibels. When we increase our color gain up to minus 9.5 decibels, what you can see is now our pulmonary vein is fully filled in. This is not changing the scale at all. It's just increasing the gain. Next, we'll talk about the color Doppler velocity scale, and this is an instrumentation setting that's used to optimize color flow based on the range of mean velocities displayed. It's usually represented as a numerical value, so either centimeters per second or meters per second, and usually our default is 50 to 70 centimeters per second, especially if we're looking for valvular regurgitation. that changing the scale has on the image is that if you have your scale set too high, it may demonstrate the appearance of lack of flow. And if it's set too low, you may see aliasing. And in this example, we can see color flow aliasing here. There's some PI present. And then when we increase the scale, we now can see laminar flow in the pulmonary artery. There are times when we do want to adjust the velocity scale to a low flow setting. And that's when we're looking at the interatrial septum to look for a rule out PFO or an ASD. What we see in this... series of video clips is that when the scale is set at 0.64 on this patient, when I play the clip, you won't see any flow going near the interatrial septum. And the problem is then we may have this set too high to be able to see a jet across the septum. By lowering the scale to 0.32 meters per second, what we can demonstrate is low flow because there's low velocity flow in the atria, and we're able to look along the septum and look for any... crossing. And so we've optimized the color flow for this particular instance when we're looking for a low flow, low velocity flow in the atria and then looking to see if anything crosses the atrial septum. Now when we're looking at regurgitant jets, it's important to have the color scale optimized or we can make things look much worse than what they are. And this is an example. This is the same patient with mitral regurgitation. And this is showing the scale set too low at point 3.35 meters per second. And what you can see is this has the appearance of a very large MR jet compared to what is the scale optimized at 0.62, where now we can clearly discern the path and the size of the jet. If the scale is set too high, what happens is we kind of lose our inflow. And so in doing so, we're probably going to underestimate the size of this jet. And here where we have it optimized at 0.62. two in this case, we can see good inflow coming in and also better discern the actual and true size of the mitral regurgitation jet. Next, we'll talk about spectral Doppler. And we'll be talking about velocity scale, the importance of sample volume size, spectral Doppler gain, sweep speed, wall filters, and then we'll discuss the differences between pulse wave Doppler. high pulse repetition frequency Doppler, continuous wave Doppler, and Doppler tissue imaging. We'll start by talking about the velocity scale. And with pulse wave Doppler, what we want to be able to do is we should see a nice envelope. And that's because this is an instrumentation setting that allows the spectral Doppler tracing to be placed as large as possible without aliasing. And when we're looking with our pulse wave Doppler, because we're setting the gate at a certain depth, we're sampling red blood cells. frequencies at just that depth. And in artery with laminar flow, what we'll see is this nice envelope and a nice spectral window. And when we're looking at that, when we then increase the scale, if you have it set too low, what you'll have is aliasing and you have this wraparound. And then if we increase the scale, that will correct the aliasing because we are adjusting our pulse repetition frequency. So when you adjust the velocity scale to eliminate aliasing, what we're doing is we're looking at how that flow is displayed. And again, we're adjusting really the pulse repetition frequency with changing in the scale. Next, we'll talk about sweep speed. And by definition, this is an instrumentation setting that allows the sweep speed to be adjusted. We want the default sweep speed to be set at 100 millimeters per second or adjusted to optimize the sweep display based on the heart rate. The fact that this is going to have on the image is if you have a slow sweep speed setting, it will allow for examination of more waveforms, and there are times where we want to do that. And when we're using respirometer tracing or evaluating for tamponade physiology, fast sweep speeds are recommended for doing measurements because they spread out the Doppler signal. And so it's ideal to set the sweep speed so that you have two to three cardiac cycles. In some instances... You may have a heart rate that determines you may need to adjust this from 100 millimeters per second to be able to display two or three cardiac cycles. But for the most part, the default is recommended to be 100 millimeters per second. And this is an example of when we would want to adjust our sweep speed to a slower sweep speed. This is looking for tamponade physiology. We see the respirometer here with expiration and inspiration. And what we're looking for is variation in our E-wave velocity. associated with tamponade physiology. When we're wanting to do measurements, we want to use a faster sweep speed. This is 100 millimeters per second. And that allows the waveform to be spread out more, and it makes it use an accuracy of measurement to know where to place your calipers for our peak velocities and then also desal time, et cetera. Next, we'll talk about the sample volume. And the importance of this is, again, when you're using pulse wave Doppler, what we're looking for is this nice spectral window and a nice envelope outlining the signal. And the reason why this is important is, again, with pulse wave Doppler, we're sampling at a specific region of interest, and most of the red blood cells will be moving at the same speed and velocity. in that area of interest. So what you end up with is each one of these little white stacks is representing a velocity. And when they're moving close to the same velocity, you'll have a spectral window in the center. What happens when you open up that gate is now you're opening up to a wider range of velocities, and we'll have loss of that spectral window. And the problem that that presents then is we can make laminar flow look like it's turbulent. So the... effect on the image that your sample volume size has is that if it's too large, the Doppler signal will look noisy, and it will give you spectral broadening, and it will make it difficult to discern laminar flow from turbulent flow. Next is the wall filter setting, and this is an instrumentation setting that allows for removal of high-intensity but low-velocity signals or clutter from the Doppler spectrum. It should be set to allow unambiguous display of the beginning and end of the flow signal of interest. And the effect it's going to have on our image is if you have high velocities present, the wall filter may need to be adjusted upward to remove the more low-level velocity clutter. And signal velocity, if it's very low, the wall filter may need to be set to a very low level to detect the Doppler signal. Like if you're doing perfusion studies, you may need to set the wall filter lower. What we're looking at here is this is looking again at a pulse wave Doppler signal from our LVOT. And what we see is that the wall filter is set too low. We have all of this clutter along the baseline, and it makes it difficult to know the timing of this waveform, to see the beginning and the end points clearly. This is the wall filter optimized, and on the system that's 200 hertz, you can clearly see the beginning and the ending of our waveform, and we've eliminated some of that low-level clutter along. the baseline. Now, this is an example with the wall filter then set to high at 250 hertz. So, what you see is you get this black band between the baseline and the start here of our Doppler signal. So, now we've eliminated too many of those low-level echoes. Next, we'll talk about spectral Doppler gain. And this is, again, an instrumentation setting that's used to adjust the overall brightness of the spectral Doppler signal. And again, the problem that we see here is that if that gain is turned down too low, this is a pulse wave Doppler from the pulmonary vein, what we can see is we cannot see our S nor our D waveform. And here we have the gain optimized, and we can clearly make out our velocities if we wanted to measure them. We also see the outline for a good assessment of the qualitative properties of this Doppler signal. Now, if the gain's too high, again, what we end up with is you have loss of the spectral window looking like it is... turbulent flow. And then also, we end up with difficulty knowing if we wanted to measure the velocities, where exactly is the peak? And this becomes critically important when we're looking at Doppler of the LVOT, where again, we want to be able to measure that modal velocity, which is the densest part of the spectrum. And again, here we see a nice window set. We're tracing the modal velocity here. We can clearly see our peak velocity. When the gain is set too high, we can overestimate that velocity and have difficulty finding the modal velocity. When it's set too low, the problem is you may be underestimating or you may not be seeing your modal velocity, so your measurements may be less accurate. Next, we'll talk about the Doppler baseline function. This is a tool that adjusts the baseline, as its name suggests, and if you have aliasing and you want to try to keep this signal as large as possible for even measurement, One of the things that you can do is you can start by adjusting the baseline and then going to adjusting your velocity scale to eliminate aliasing. In this case, we were only interested in flow going away from the transducer so we could adjust the baseline up. Now, sometimes it may be that you have to go right to adjusting the scale to eliminate the aliasing because you want to show, like in the instance of continuous wave Doppler through the pulmonic valve, where you may want to show forward flow and if there's a regurgitant jet. showed the jet at the same time, then you're going to want to be able to show flow both above and below the baseline. Next, we'll talk about pulse wave Doppler. And in pulse wave Doppler, this allows us the ability to interrogate blood flow velocities at a specific depth or region of interest by where we set our gate. The transducer emits a pulse, and it's going to go to the specified depth that you've set with your gate. And then it listens and waits. for the reflected frequency of the red blood cells to come back. The velocity is then calculated by the system using the Doppler equation. Now, because there is a waiting period, it emits the signal, and then it waits for the returning of the frequency. there is a limit to how fast it can accurately measure those velocities. And that limit is known as the Nyquist limit. So when we exceed the Nyquist limit, the effect is aliasing. And how you determine the Nyquist limit is that it is one-half of the pulse repetition frequency, or one-half your sampling rate is when the Nyquist limit is exceeded. Pulse repetition frequency is determined primarily by the velocity scale. and it's limited by your imaging depth. So we can start to eliminate aliasing by increasing the velocity scale. You can also adjust the baseline. And if aliasing cannot be eliminated in normal pulse wave mode by maximizing the scale, we can switch to high pulse repetition frequency. And what this does is it can increase the number of active sample volumes. So high pulse repetition frequency Doppler utilizes multiple sample volumes to increase the max maximum velocity that can be detected. And here we see the 2K. And in this example, we'll have two pulses that are sent in succession from the transducer. So here's pulse one going to sample volume one. Here's pulse two. Now, as that first pulse is returning, it's going to overlap with the second pulse. And then these two pulses will reach the transducer at the same time. So the ultrasound system cannot discern the depth of these overlapping pulses. And then that sets up our limitation for high pulse repetition frequency Doppler, which is range ambiguity. Because again, the system cannot tell from which step these returning echoes come when the pulses are overlapping. With continuous wave Doppler, this is a technique in which the transducer is continuously sending pulses and receiving reflected red blood cell frequency shifts. There's no wait time, so there's no Nyquist limit. And because of that, the advantage of continuous wave Doppler is that it allows us to accurately measure high velocity. Now, the limitation is when we're constantly sending and constantly receiving along this line is that our high velocity could come from anywhere in this path. So with continuous wave Doppler, we cannot determine the precise location of the high velocity, and that's known as range ambiguity. Next, we'll talk about Doppler tissue imaging. By definition, this is a technique used to measure the Doppler frequency shift of the moving myocardium and the annuli of the mitral and tricuspid valves. It's different than conventional pulse wave Doppler, which is used to assess blood flow velocity. And that's because blood flow is high velocity and low amplitude signal. With Doppler tissue imaging, we're looking at the myocardium. And the myocardial Doppler signals are low velocity, usually less than 20 centimeters per second, and high amplitude, usually greater than 40 decibels. Therefore, we need a different preset. And the Doppler tissue imaging preset should be set to optimize for low velocity, so a scale less than 25 centimeters per second or lower, and a higher amplitude. So we need to adjust the wall filter setting. And this is showing an example of where we see... see an optimized DTI preset where we're clearly seeing our E prime and A prime and S prime waveforms. And what we're able to do is through adjusting the wall filter and our scale setting to be much lower, we can have accurate depiction of the myocardial Doppler. This is using the same patient, but using the standard setting for the pulse wave Doppler. And you can see this is an uninterpretable signal for measurement and looking at our myocardial Doppler. signal. Next, we'll talk about M-mode, and we'll talk about M-mode sweep speed, durable M-mode, and color M-mode. By definition, this is an instrumentation setting used to optimize the timing of events in M-mode displays. The default is usually 100 millimeters per second. The effect on the image is that we can, through adjusting the sweep speed the same as Doppler, we can determine the number of cardiac cycles visualized. Faster sweep speeds of 100 millimeters per second are better for measurement. Slower sweep speeds are better for certain physiologic conditions when, again, we want to see changes with time and we want to demonstrate more cardiac cycles. And this is just an example showing a sweep speed of 25 millimeters per second where we see more cardiac cycles and then as we switch it to 50 millimeters per second. Color M-mode can also be used, and by definition, this is an instrumentation setting that's used to integrate the color Doppler image with the M-mode tracing. The benefits of this are that the timing of certain color flow events within the cardiac cycle can be better depicted. So we can really time the insufficiency jet. And we can also evaluate left ventricular inflow propagation velocity. This is an example that shows a color M mode that assists with the timing of events. And the image on the left is demonstrating our grayscale M mode with mitral stenosis. The image on the right is showing the M mode with mitral stenosis and diastole. And then our regurgitant jet demonstrated in systole. And again, you can appreciate the timing of events using color M mode. Steerable M-mode is another feature. This is linear measurements are overestimated when obtained of likely to the structure of interest. So if you're using your standard M-mode and it's perpendicular to the structure, but if you have a tip tart or a tart that's off axis, they're not going to be accurate. So what steerable M-mode or anatomic M-mode does is it allows you to steer the M-mode cursor like we can with our Doppler cursor. and it will align, then you can align it perpendicular to your structure of interest. The image, however, is created from a selective display of part of the 2D image. So when you use a cerebral N-mode or anatomic correction N-mode, your temporal and range resolution are no better than if you're using your 2D measurements and image parameters. So now we're going to review some of our objectives, and then we'll open up for questions. But we'll start by talking about, this is an image. And you can see it's too dark. It's too dark to discern really our myocardium. It's definitely difficult to see our endocardial and blood tissue interfaces. And so we know we need to correct. Now, another feature is I can tell you the dynamic range is 50 decibels. So if I see that on an image, what would be the best place to start with adjusting from an instrumentation perspective? Because we know that... 70 to 75 decibels is a better dynamic range for cardiac imaging and depicting the myocardium, the non-compact and compact myocardium differences, and then also endocardial tissue borders. We would start by adjusting this. Overall gain would adjust the overall brightness, but it's not going to change the number of gray shades that we have available to us. Time gain compensation, this image is pretty uniform right now. And if we switch to decolorization, again, it's not giving us any more shades of gray to work with, which is what the problem is with this image. So this image, knowing that it's at 50 decibels dynamic range, would be the appropriate change to make first. Then you may need to adjust these other features. Next, which scanning maneuver is being demonstrated to center the LVOP? So this is our... scanning movement that we're doing. We're staying in the same plane. It's a small motion. And what we're doing is we are doing a maneuver with the transducer to center the LVOT and align it more perpendicular for measurement. And this maneuver would be the rocking maneuver. Next. Which of the following could be adjusted to eliminate aliasing in this example? And our choices are increased Doppler gain. Well, that's not going to eliminate aliasing. That's just going to fill in our Doppler spectrum and make it look more noisy. Increase the wall filter setting. We don't have a lot of clutter here along the baseline, and we don't have a wide black gap indicating that the wall filter is too high. Decrease the sample gate size. we can look at what our measurement is. It's pretty narrow, so it's small. We know if we make it bigger, we would lose this window and make it look like turbulent flow when it isn't, perhaps. And then we can increase the velocity scale. And what we're doing with the velocity scale is we're increasing our pulse repetition frequency, and that's what's going to eliminate aliasing. Next, is this image optimized? to evaluate mitral regurgitation. So you're looking at it. We see this large jet. We look at our scale. It's set at 0.35, and that's too low. So this is not optimized to evaluate this jet. When we adjust the scale to 0.62, we now can see adequate depiction of our mitral regurgitation. And now we have optimized our image. So to review, the pulse wave Doppler, the advantage we talked about was range resolution. Because we can set that gate at a specific depth, we know that we're sampling velocity information from that depth. The limitation is aliasing. And again, aliasing will occur when we exceed one-half the pulse repetition frequency. Continuous wave Doppler, the advantage is that it can accurately measure high velocities. The limitation is range ambiguity. And what that means is because we have an interrogation line and we're sampling continuously all along that line and also receiving the reflected frequencies all along that line, we can't say for sure where that high velocity is. velocity comes along that line of interrogation. So, that's known as range, which is another term for depth and ambiguity. So, we aren't sure of what depth that velocity is coming from. Thank you for your attention, and we'll now open it up for questions. And we'll start with, what would you say is the main three changes to this document from previous documents? And I guess to summarize it, I think the main thing is that we want to, what we really put in a lot of work in this document too were the how-tos. So how to know if your instrumentation is set up correctly. We do really want to encourage people to meet with your application specialist too when you're setting your presets. Look at the different grayscale maps. Look at the patient population that you have coming in. And then we also wanted to offer just some scanning tips. Next, there's a question about, there seems to be difficulty in understanding the difference between tilting, rocking, and angling. How can we distinguish clearly between these maneuvers? And this was another struggle we had as a writing group. And there was a document existing from the American Institute of Ultrasound and Medicine, and that's really where we used then their definition of tilting. And I'm going to go back to the slide for just a second here. And what our hope with kind of putting this together and starting to use the same terms across disciplines, such as what the AIUM already was using, what was already available in some of the ECHO textbooks, is to start to use the same terms. So tilting, we're referring to your kind of fixing your transducer, and then you're going to change the plane that you are cutting through. Rotating, everyone kind of uses that very similar. And again, that's just rotating, keeping your transducer fixed and just rotating the orientation index. Sliding is also standard. Rocking and angling, angling also was another one that was pretty standard as far as kind of directing the beam towards your structure of interest. And then rocking, again, we used with looking at the AIUM literature and also what had been doing. published in the ECHO literature previously to discern those maneuvers. So rocking is just a small maneuver that you're using to center a structure and you're staying in the same image plane. Tilting, you're going through other planes. Next, there's a question, what is the recommended pulse wave sample volume for spectral Doppler velocity and tissue Doppler? And what I guess we're looking at is you'd want to work with your application specialist to design a preset. One of the things that we're looking at here is that you for sure want to have a lower velocity scale set below less than 25 centimeters per second. Your wall filter should be set for high amplitude signals, again, greater than 40 decibels. And then also, sorry, looking at the question here again, you use a larger volume samples than what you do with your pulse wave Doppler. Another question is, are there any rules about what color scale setting we should use? And it's recommended to start with 50 to 70 centimeters per second. Another question was posed regarding rocking and angling. Are they the same or what is the difference? Again, rocking is staying in the same plane and your goal is to center the structure. Angling is you're directing the beam so you are directing it towards focusing in on, in this case, the best example is really looking at your tricuspid valve and then angling. more leftward in this case to look at the pulmonic valve. Do you find over-measuring spectral Doppler waveforms by not measuring the modal velocity? I think one of the things that's important to do when you're looking at and for the modal velocity is to make sure that your gain settings are set accurately. And if you are using pulse wave Doppler and you believe the flow is laminar, you should see that window. And if you're not seeing that window, you may be over-gained. You may have a sample volume. that's too large, those would be things to start with. Another question, can you review the difference between gain, dynamic range, and grayscale maps again? So what grayscale maps are showing us is this is how we're going to display the brightness of the amplitude signals returning. And we can choose to kind of suppress and enhance different... signals in different ways. It's not changing the number of shades of gray, though. It's changing how we choose to display them and what brightness we want to display them at. For dynamic range, what we're actually doing is we are determining the number of grayscale values that we want to use. So the number of shades of gray. So they are different. This is... brightness level on your monitor, how you're going to see it. This is determining the actual number of grayscale values you're going to use. Again, there's more questions. The peristernal long axis, could you review the peristernal long axis technique as another question? So typically, you're going to... start with your orientation marker on the patients in the left lateral decube as long as they can move the orientation marker should be directed towards the patient's right shoulder we're cutting along the long axis of the heart and what we're looking to identify is you want to kind of have your left ventricle your septum stretched out here we want to be perpendicular to the structures the structures that are viewed in our starting image are the left atrium the micro valve the left ventricle, the left ventricular outflow tract, aortic valve, ascending aorta, and the right ventricle. And there's another question, is 100 millimeters per second the speed recommend for all measurements? And yes, that is the recommendation for all our Doppler and M-mode measurements. However, again, depending on the patient's heart rate, you may need to adjust that. It's ideal to really show... two to three cardiac cycles, that's going to help you with just looking at measuring time intervals. However, if you need to get a good measurement, you still want to be able to spread out your Doppler signal or your M-mode, and that will make it easier to have an accurate measurement. There's another question. How is grayscale different than gain? Gain is just adjusted the overall brightness of the echoes as they return. So as all of the echoes return back to the transducer and ultrasound system, gain is going to uniformly, however you have that set, amplify all of those echoes across your entire image. Gray scale is we actually are choosing, based on a post-processing map, how when those signals come back, what brightness we're going to give them. And that's based on the gray scale map. that you choose. So it's not going to uniformly increase them. It's not something that the user is doing real time. It's something you can adjust based on, again, what map you pick. And again, it's going to be how you display all of those amplitude signals as they come back to the system, not amplifying them all uniformly. So, one of the things, there's a question about ultrasound systems used for the presentation. And we did use multiple different systems for both the guideline document and putting together the images for this presentation. It is important to note that, you know, while all systems have these controls and these instrumentation settings, they may have slightly different names. And I guess, you know... We didn't specifically write protocols per machine for the guideline document nor the webinar. And what we would do is we would encourage, based on this information and, you know, how you want to set your presets based on a grayscale map that will help you discern your endocardial tissue borders best. differentiate between the compact and non-compact myocardium. We would want you to work with your application specialist to go through those post-processing or grayscale maps with you and help you discern based on your patient population what would be the best one to give you that information. The same is true. We would want you to set your sweep speeds at 100 millimeters per second or to know that's the recommended guideline. And again, to work with the application specialist so you can optimize your own system that you're using to kind of match the criteria that we stated in the guidelines as close as possible. But because each system calls to control something slightly different, we didn't go through and list out kind of official presets for each piece of equipment that could be used. And also... Just people may have different makes and models of equipment and different software versions as well. And I think we have concluded our time here. Well, thank you, everyone, again, for your attention and time today.

So without any further delay, let me introduce today's speaker. Dr. Carol Mitchell is an assistant professor in the Department of Medicine at the University of Wisconsin-Madison School of Medicine and Public Health. She currently teaches an introduction to vascular ultrasound course to the cardiovascular fellows and instructs teaching labs for graduate student courses in the Department of Medical Physics. She's previously been a program director for diagnostic medical sonography programs, served as chair. for the Joint Review Committee on Education in Diagnostic Medical Sonography.

She's a commissioner of the Commission on Accreditation of Allied Health Education Programs, is a member of the Cardiovascular Credentialing International Advanced Cardiac Sonographer Credentialing Exam Committee, served on numerous committees of the American Society of Echocardiography, and is currently serving on the American Board of ASC's Board of Directors in the role of treasurer. It is my pleasure to turn the webinar over to Dr. Carol Mitchell. Thank you so much.

Thank you for the opportunity to present part one of this two-part webinar. Today's lecture will focus on nomenclature and instrumentation as it relates to the ASC guidelines for the performance of the comprehensive transthoracic echocardiogram in adult patients. I'd like to begin with some acknowledgments, and I would like to thank and recognize the members of the writing group and the expert sonographers that also contributed to images for this webinar and the content for the guidelines.

I'd also like to thank the ASB members of the Guidelines and Standards Committee and Board of Directors for their very thorough review and, again, providing expertise and guidance into the development of this guideline and this webinar today. Our learning objectives for today will be to describe the... scanning maneuvers of tilting, rotating, sliding, rocking, and angling, and how they are used to optimize image acquisition. We will also state how the following instrumentation controls affect an ultrasound image to include discussion on grayscale map, dynamic range, overall gain, and time gain compensation.

We'll also describe why optimizing the color Doppler scale setting is important to evaluate low flow states and how the setting may influence the appearance of regurgitant jets. We'll also describe how the spectral Doppler settings can be optimized for performing Doppler tissue imaging, and we'll list the advantages and limitations of pulse wave and continuous wave spectral Doppler. We'll begin with discussion of the scanning planes, image acquisition windows, and scanning maneuvers. So, to review the scanning planes that we'll be talking about, we'll be looking at the long axis. where we acquire our parasternal long axis images, and that's along the long axis of the heart from the apex to the great vessel.

We'll talk about the short axis plane, which is a cross-section of the left ventricle demonstrated here, and this is how we image the heart in a series of axial planes. And then we'll talk about the apical plane, where we see the apical four-chamber view. The scanning movers we'll begin discussing are tilting, rotating, sliding, rocking, and angling.

The tilting maneuver is done by maintaining kind of a fixed base on the transducer on the heart, and then we're going to tilt anterior and posterior to see our different imaging planes. An example of this is diagrammed here in our schematic drawing showing we're imaging from the apical window, and our first imaging plane is very posterior where we see the coronary sinus. Then as we tilt anterior, we would come into the four-chamber view.

then into the LVOT and aortic valve and ascending aorta or the five-chamber view. And then in some adults and routinely in P's, we're able to continue imaging anterior and see the right ventricular outflow tract, pulmonic valve, and main pulmonary artery. This video clip starts really at about section three of our somatic drawing. We're starting by imaging the apical four-chamber view. And then as we tilt anterior.

We'll come into the view where we see the LVOT, aortic valve, and ascending aorta. And then as we continue to tilt anterior, we'll see the RVOT. the pulmonic valve, and the main pulmonary artery. The next maneuver we'll discuss is rotating.

And this view or maneuver is done routinely when we rotate from a long axis view to a parasternal short axis view. The movement of the transducer is we keep the transducer in the same location and we just change the orientation index. So here we've rotated 90 degrees to move from a parasternal long axis view to the short axis.

view. And that's what our diagram is showing here. Again, we're longitudinal. The orientation index is aligned towards the patient's right shoulder.

We're going to rotate at 90 degrees. And then what we would do when we're imaging is you would kind of slide your transducer so you're directly over the aortic valve, then rotate it 90 degrees. And then we would rotate into a view where we're now at short axis on the aortic valve. And this would start our parasternal short axis.

fuse at the level of the great vessel, and then we can utilize a maneuver called sliding. And what this is, is this is where we're going to physically move the transducer. This is typically done in the short axis plane when we need to move in between intercostal spaces to stay perpendicular to the anatomy of interest at each level in our short axis fuse.

So an example of this would be starting at the level of the great vessels where we see the aortic valve, and then in order to say kind of on axis, we would need to physically slide the transducer lower on the body to then demonstrate the apical area. The next maneuver we'll discuss is rocking. Rocking is a small maneuver that is used to center a structure.

And so this is routinely done when you're imaging in the parasternal long axis view. And we're starting with our nice long axis view showing the left ventricle. we want to bring the LVOT and the aortic valve slightly more horizontal.

What we can do is rock towards the index marker that we're showing here, rocking away and then rocking towards the index marker. And in doing so, what we can do is bring this LVOT and aortic valve more horizontal and more perpendicular. So it will allow for an easier and more accurate measurement of the LVOT and aortic annulus.

And then we can zoom on that view and also maintain a nice perpendicular orientation to our structure of interest. Next, we'll talk about angling. And what angling is, is it's a small maneuver that's done. Instead of trying to center a structure, we use angling to direct the sound beam towards our structure of interest.

So in this example, what we're showing with the motion of the transducer is we're angling rightward on the heart to demonstrate and focus in on the tricuspid valve. And what that would look like during our echocardiogram examination is this view here, where we see the right atrium, the tricuspid valve, and then angling more leftward in position, we can focus in on the pulmonic valve. And here we see the RVOT, the pulmonic valve, and the main pulmonary artery. So this is an example of the scanning maneuver angling.

We'll next review our image acquisition windows, and we'll start by looking at the parasternal views. These are often, as long as the heart is levocardia, the apex pointed towards the left, we'll obtain our parasternal long axis and parasternal short axis views from this window. The apical window is where we'll do our series starting with the apical floor chamber view and then moving through the apical views. The subcostal window, our starting view will be the four-chamber view.

The right parasternal window in adults is predominantly used to locate the ascending aorta and then to identify kind of our angle of incidence replacement of the PEDOS transducer to get our most accurate Doppler measurements, like in cases of aortic stenosis. And then the suprasternal notch view, which is used for imaging of the aortic arch. So just to review kind of our starting positions for acquiring these images.

In the parasternal window, we'll start with the patient in the left lateral decubitus position. The index marker is towards the patient's right shoulder. And our starting view is going to be the parasternal long axis view, which we see here. The left atrium, the mitral valve, left ventricle, LVOT, aortic valve, ascending aorta comes this way, and the right ventricle.

The next... window is going to be the apical window and patient is again in the left lateral decubitus position. It's best if you have a cutout bed so that you can get the proper orientation to the apex.

without having to reach so much as a sonographer. The index marker is going to be pointed towards the 4 or 5 o'clock position, and the starting view is going to be our apical floor chamber view. And often you'll find the best window under the breast tissue and ceiling for the apical impulse. And this is our starting view then, the apical floor chamber view, where, again, we'll see the left atrium, left ventricle, right atrium, right ventricle.

Then we'll move to our next... position, which is the subcostal view. For this view, the patient is rolled into a supine position. The index marker is pointed towards the patient's left side at the three o'clock position.

And the starting view is going to be our subcostal four chamber view. And what we see here is going to be the left atrium, the micro valve, the left ventricle, right atrium, tricuspid valve, right ventricle. Now, some tips for getting this image are oftentimes when we roll the patient, their legs will be extra.

extended. And if you notice when you're pushing on the abdomen to angle up under the xiphoid to get this view, if the patient is kind of tensing against you, oftentimes if you just have them bend their knees up, that will relax the abdominal muscles and it may make getting the view a little easier. Another tip would be to slide a little more rightward and use a little more of the liver as your window for being able to get this view. Next is the right parasternal image acquisition window.

And for this window, we're going to roll the patient into a right lateral decubitus position, extend the right arm above the head. The index marker is going to be towards the patient's right shoulder. And what you're trying to do is image in a plane that you're going to see the ascending aorta coming directly out of the heart. And we're trying to align nice and parallel for it for a good Doppler angle. The starting view is going to be looking for the ascending aorta.

And again, in adults, this is predominantly used for locating the ascending aorta and then placement of the PDOS transducer. So what that's going to look like is this is the ascending aorta coming up and out of the heart. And then we can take a Doppler while we're imaging it. But again, also, this is a good way to identify the ascending aorta for placement of the blind continuous wave Doppler transducer. Next is the suprasternal notch image acquisition window.

Again, the patient's going to be in a supine position. The index marker is going to be towards the patient's left shoulder, and you may have to do small rotations between kind of a 12 o'clock and 1 o'clock position. And the starting view is going to be long axis of the aortic arch. Now, if you start with your probe too perpendicular, you're going to have difficulty getting this arch stretched out.

So one of the things that we tell our... students to do is if you can tip the face of the transducer inferiorly so that you are aligning almost parallel to the neck, you may have better luck stretching out the ascending aorta, transverse arch, and then the descending aorta. Next, we'll talk about 2D B-mode instrumentation settings, and we'll be discussing grade scale maps, dynamic range, overall gain, and time gain compensation. So, we'll start with discussing grade scale maps.

And this is an instrumentation setting that adjusts how the shades of gray will be displayed on the image. So it's not adjusting the number of the shades of gray. It's adjusting how bright you're going to assign each amplitude of the signal that's returning to the ultrasound system.

So the effect that it's going to have on the image is it determines how the shades of gray will be displayed. And the operator can select based on specific findings of the image. And in the olden days, we used to be able to bring up something called our post-project. processing curve and you see kind of a gamma curve.

And what we're looking at here is we have our gray scale bar and it would kind of tell us how our range is being displayed of our brightness. And this is just a linear map. So it's kind of showing an equal brightness assigned to the blacks and whites. Other post-processing curves may look different and we can kind of choose how we want to enhance and suppress signals.

So this is an example of on one ultrasound system just using grayscale map F compared to grayscale map A. On this system, map A is the most linear of the grayscale maps, so this is a more equal representation. But depending on your lab, what you want to make sure is that you have a preset selected that's going to give you the best definition of your endocardial tissue borders and also help you discern your compact and non-compact myocardium.

to make the most accurate measurement. B-mode colorization is another tool that we can use. What this does is it transforms the grayscale image to a different range of colors and this is really based on lab preference. It may demonstrate certain pathologies better, and there are certain interpreting physicians who may like you to use a certain colorization because it helps them see certain pathologies better.

The effect that it has on the grayscale image is that essentially it's just colorizing the map that you have to a different set of colors. So this is sepia in this case. It does not change the amount or the type of information displayed, only the perception for the viewer. And this is just looking at this real-time, again, map eye in the grayscale, and then colorizing that to sepia, but we're still using the map eye. Next, we'll talk about dynamic range.

And this is the ratio between the highest and lowest received echo amplitudes in the image. By adjusting this setting, it adjusts the appearance of the shades of gray on the image. So a low dynamic range setting yields an image that is very black and white. very high contrast as seen here with a dynamic range of 50 decibels compared to a dynamic range of 75 decibels. A high dynamic range setting produces an image that has more shades of gray as seen here.

And the reason why is it has a smaller range of amplitudes that's assigned to a particular shade of gray making up the image. So if we have more shades of gray, we can kind of disperse those amplitudes differently. And in cardiac imaging, we want to provide enough shades of gray to discern the interface between the compacted and non-compacted myocardium. And if we look at this in real time, most systems that report dynamic range in decibels will have a range between 70 and 75 decibels for cardiac imaging.

When you're looking at a dynamic range of 50 decibels on this system, what you can see is this is a much more black and white image. We lose detail regarding the myocardium. here and it's harder to discern our borders for accurate measurement. So in summary, while grayscale maps and dynamic range appear to do similar things to your image as to how the grays are displayed, they are actually doing different things.

With the grayscale maps, they're going to adjust the brightness level for each shade of gray. What dynamic range instrumentation does is it determines the number of grays. scale values or the number of gray shades to be displayed.

Next, we'll talk about overall gain. And by definition, this is an instrumentation control that adjusts the brightness of the image and it does it equally throughout the entire sector. So the effect that it has on your image is the overall brightness.

And the gain should be set just high enough so that there are just a few echoes demonstrated in the blood and the blood endocardial tissue borders are well delineated. So this is an appropriately gained image at 4 decibels, and this would be an undergained image. And again, you see the loss of detail as being able really to discern our blood endocardial tissue quarters.

This is looking at the clips in real time. So again, appropriately gained image and an undergained image. Next, we'll talk about time gain compensation.

And this is usually represented as a series of pods that can be adjusted in a... certain area to amplify a particular portion of the image. Usually it's a curve like this because the deeper the sound travels in the body, the more attenuation.

And so what we're doing is we're doing selective amplification so we have an evenly bright image. And what we see here is we're selecting our pods to optimize our image so we have an equal brightness throughout the image. And then this is an example of inappropriate image.

that TGC pods. And what you can see is that we've completely suppressed the amplification of the echoes in these regions. And how that affects the image, or you see these focal bands across these areas.

And if we look at this image in real time, again, this is the same patient here and here, just with appropriately set time gain compensation controls here. And again, the appearance of the focal banding when the TGC is not set correctly. There is a feature on most ultrasound systems now that's called an automatic ultrasound optimization feature. It has different names based on the vendor.

But what it does is it's a function that allows you to rapidly and automatically adjust the TGC. So from the image before where our pods were set inappropriately, we can hit this automatic ultrasound optimization feature, and it gives us a quick correction to the image. So it selectively amplifies the echoes.

that are returning based on the appearance of structures across the image. And it is considered a time-saving feature, particularly if maybe you're doing a bedside and you're having to do lots of preaching because you can't get your system as close as you would like to. It may be a feature that helps you.

Having said that, oftentimes there is still opportunity for some manual adjustment to fully optimize the image. But this is a good, quick starting point. This is showing, again, just use on the same image that we showed with the TGC set wrong before using the automatic ultrasound optimization feature. Then the sonographer manually also did a few tweaks to the DGC after using the auto-optimization feature. Next, we'll talk about frame rates.

High frame rates are important in echocardiography because we want to maximize our temporal resolution. The heart is a feeding structure, so our higher frame rates are going to show the real-time motion better. Things that you can do to increase frame rate are decrease the depth of your imaging, decrease the sector size, decrease the number of focal zones, and reduce the number of scan lines being written per sector sweep.

And this is an example of how these tools affect frame rate. So this is a depth of 170 millimeters. These three image clips are all taken from the same patient. And then this is with a narrow sector width, and you can see our frame rate is at 84 Hz. This is increasing the depth to 240 mm.

The sector width is still narrow, but our frame rate has dropped to 73 Hz. And then if we increase the depth to 240 mm and open our sector width as wide as it will go, our frame rate drops to 43 Hz. And if you just concentrate on looking at this image compared to this image, What you can see is that this one has a much lower frame rate. The temporal resolution is much poorer.

And again, it can be optimized by decreasing the depth and narrowing our sector width. Next, we'll talk about color Doppler imaging instrumentation settings. And we'll be discussing the region of interest, the color Doppler velocity scale, color gain, velocity scale, and how you can optimize it for laminar versus turbulent flow.

when you might want to use higher and lower settings. So we'll talk first of all about our region of interest. And this is an instrumentation setting that defines the size and position of the region of the color interrogation within your B-mode image.

And we typically call this the color box. And what we're looking at is how the size of this affects your frame rate. Setting that region of interest as narrow and as shallow as possible allows for maximum frame rate.

and velocity scale. And so it yields the best temporal and flow velocity resolution. And just looking at these in real time, again, this is our narrow sector, and we have a frame rate of 35.6 frames per second. When we open that up wider, what you can see is blurring of the color, poor temporal resolution, and our frame rate drops to 14.9 frames per second.

So again, the tighter you can make this... The shallower you can place it by adjusting depth, the faster your frame rate is going to be. Next, we'll talk about the color Doppler gain feature.

And this is an instrumentation setting that's used to demonstrate optimum color fill and anatomic structures. And the way that you optimize this is you start by turning your color gain all the way up until you see speckles just outside your area of interest. And then you slowly turn it down until you have fill within the structure of interest. and no more speckling outside of that.

And the effect that the color gain has on the image is that it amplifies the color Doppler signal to demonstrate color flow in these anatomic structures. And if we look at this real time, this is imaging of the pulmonary vein, and this is a color flow Doppler gain setting at minus 17 decibels. When we increase our color gain up to minus 9.5 decibels, what you can see is now our pulmonary vein is fully filled in.

This is not changing the scale at all. It's just increasing the gain. Next, we'll talk about the color Doppler velocity scale, and this is an instrumentation setting that's used to optimize color flow based on the range of mean velocities displayed. It's usually represented as a numerical value, so either centimeters per second or meters per second, and usually our default is 50 to 70 centimeters per second, especially if we're looking for valvular regurgitation.

that changing the scale has on the image is that if you have your scale set too high, it may demonstrate the appearance of lack of flow. And if it's set too low, you may see aliasing. And in this example, we can see color flow aliasing here.

There's some PI present. And then when we increase the scale, we now can see laminar flow in the pulmonary artery. There are times when we do want to adjust the velocity scale to a low flow setting.

And that's when we're looking at the interatrial septum to look for a rule out PFO or an ASD. What we see in this... series of video clips is that when the scale is set at 0.64 on this patient, when I play the clip, you won't see any flow going near the interatrial septum.

And the problem is then we may have this set too high to be able to see a jet across the septum. By lowering the scale to 0.32 meters per second, what we can demonstrate is low flow because there's low velocity flow in the atria, and we're able to look along the septum and look for any... crossing.

And so we've optimized the color flow for this particular instance when we're looking for a low flow, low velocity flow in the atria and then looking to see if anything crosses the atrial septum. Now when we're looking at regurgitant jets, it's important to have the color scale optimized or we can make things look much worse than what they are. And this is an example.

This is the same patient with mitral regurgitation. And this is showing the scale set too low at point 3.35 meters per second. And what you can see is this has the appearance of a very large MR jet compared to what is the scale optimized at 0.62, where now we can clearly discern the path and the size of the jet. If the scale is set too high, what happens is we kind of lose our inflow.

And so in doing so, we're probably going to underestimate the size of this jet. And here where we have it optimized at 0.62. two in this case, we can see good inflow coming in and also better discern the actual and true size of the mitral regurgitation jet. Next, we'll talk about spectral Doppler. And we'll be talking about velocity scale, the importance of sample volume size, spectral Doppler gain, sweep speed, wall filters, and then we'll discuss the differences between pulse wave Doppler.

high pulse repetition frequency Doppler, continuous wave Doppler, and Doppler tissue imaging. We'll start by talking about the velocity scale. And with pulse wave Doppler, what we want to be able to do is we should see a nice envelope. And that's because this is an instrumentation setting that allows the spectral Doppler tracing to be placed as large as possible without aliasing.

And when we're looking with our pulse wave Doppler, because we're setting the gate at a certain depth, we're sampling red blood cells. frequencies at just that depth. And in artery with laminar flow, what we'll see is this nice envelope and a nice spectral window.

And when we're looking at that, when we then increase the scale, if you have it set too low, what you'll have is aliasing and you have this wraparound. And then if we increase the scale, that will correct the aliasing because we are adjusting our pulse repetition frequency. So when you adjust the velocity scale to eliminate aliasing, what we're doing is we're looking at how that flow is displayed.

And again, we're adjusting really the pulse repetition frequency with changing in the scale. Next, we'll talk about sweep speed. And by definition, this is an instrumentation setting that allows the sweep speed to be adjusted. We want the default sweep speed to be set at 100 millimeters per second or adjusted to optimize the sweep display based on the heart rate.

The fact that this is going to have on the image is if you have a slow sweep speed setting, it will allow for examination of more waveforms, and there are times where we want to do that. And when we're using respirometer tracing or evaluating for tamponade physiology, fast sweep speeds are recommended for doing measurements because they spread out the Doppler signal. And so it's ideal to set the sweep speed so that you have two to three cardiac cycles. In some instances...

You may have a heart rate that determines you may need to adjust this from 100 millimeters per second to be able to display two or three cardiac cycles. But for the most part, the default is recommended to be 100 millimeters per second. And this is an example of when we would want to adjust our sweep speed to a slower sweep speed. This is looking for tamponade physiology. We see the respirometer here with expiration and inspiration.

And what we're looking for is variation in our E-wave velocity. associated with tamponade physiology. When we're wanting to do measurements, we want to use a faster sweep speed.

This is 100 millimeters per second. And that allows the waveform to be spread out more, and it makes it use an accuracy of measurement to know where to place your calipers for our peak velocities and then also desal time, et cetera. Next, we'll talk about the sample volume.

And the importance of this is, again, when you're using pulse wave Doppler, what we're looking for is this nice spectral window and a nice envelope outlining the signal. And the reason why this is important is, again, with pulse wave Doppler, we're sampling at a specific region of interest, and most of the red blood cells will be moving at the same speed and velocity. in that area of interest.

So what you end up with is each one of these little white stacks is representing a velocity. And when they're moving close to the same velocity, you'll have a spectral window in the center. What happens when you open up that gate is now you're opening up to a wider range of velocities, and we'll have loss of that spectral window. And the problem that that presents then is we can make laminar flow look like it's turbulent.

So the... effect on the image that your sample volume size has is that if it's too large, the Doppler signal will look noisy, and it will give you spectral broadening, and it will make it difficult to discern laminar flow from turbulent flow. Next is the wall filter setting, and this is an instrumentation setting that allows for removal of high-intensity but low-velocity signals or clutter from the Doppler spectrum. It should be set to allow unambiguous display of the beginning and end of the flow signal of interest.

And the effect it's going to have on our image is if you have high velocities present, the wall filter may need to be adjusted upward to remove the more low-level velocity clutter. And signal velocity, if it's very low, the wall filter may need to be set to a very low level to detect the Doppler signal. Like if you're doing perfusion studies, you may need to set the wall filter lower.

What we're looking at here is this is looking again at a pulse wave Doppler signal from our LVOT. And what we see is that the wall filter is set too low. We have all of this clutter along the baseline, and it makes it difficult to know the timing of this waveform, to see the beginning and the end points clearly. This is the wall filter optimized, and on the system that's 200 hertz, you can clearly see the beginning and the ending of our waveform, and we've eliminated some of that low-level clutter along.

the baseline. Now, this is an example with the wall filter then set to high at 250 hertz. So, what you see is you get this black band between the baseline and the start here of our Doppler signal.

So, now we've eliminated too many of those low-level echoes. Next, we'll talk about spectral Doppler gain. And this is, again, an instrumentation setting that's used to adjust the overall brightness of the spectral Doppler signal.

And again, the problem that we see here is that if that gain is turned down too low, this is a pulse wave Doppler from the pulmonary vein, what we can see is we cannot see our S nor our D waveform. And here we have the gain optimized, and we can clearly make out our velocities if we wanted to measure them. We also see the outline for a good assessment of the qualitative properties of this Doppler signal.

Now, if the gain's too high, again, what we end up with is you have loss of the spectral window looking like it is... turbulent flow. And then also, we end up with difficulty knowing if we wanted to measure the velocities, where exactly is the peak? And this becomes critically important when we're looking at Doppler of the LVOT, where again, we want to be able to measure that modal velocity, which is the densest part of the spectrum. And again, here we see a nice window set.

We're tracing the modal velocity here. We can clearly see our peak velocity. When the gain is set too high, we can overestimate that velocity and have difficulty finding the modal velocity. When it's set too low, the problem is you may be underestimating or you may not be seeing your modal velocity, so your measurements may be less accurate. Next, we'll talk about the Doppler baseline function.

This is a tool that adjusts the baseline, as its name suggests, and if you have aliasing and you want to try to keep this signal as large as possible for even measurement, One of the things that you can do is you can start by adjusting the baseline and then going to adjusting your velocity scale to eliminate aliasing. In this case, we were only interested in flow going away from the transducer so we could adjust the baseline up. Now, sometimes it may be that you have to go right to adjusting the scale to eliminate the aliasing because you want to show, like in the instance of continuous wave Doppler through the pulmonic valve, where you may want to show forward flow and if there's a regurgitant jet.

showed the jet at the same time, then you're going to want to be able to show flow both above and below the baseline. Next, we'll talk about pulse wave Doppler. And in pulse wave Doppler, this allows us the ability to interrogate blood flow velocities at a specific depth or region of interest by where we set our gate. The transducer emits a pulse, and it's going to go to the specified depth that you've set with your gate.

And then it listens and waits. for the reflected frequency of the red blood cells to come back. The velocity is then calculated by the system using the Doppler equation.

Now, because there is a waiting period, it emits the signal, and then it waits for the returning of the frequency. there is a limit to how fast it can accurately measure those velocities. And that limit is known as the Nyquist limit. So when we exceed the Nyquist limit, the effect is aliasing. And how you determine the Nyquist limit is that it is one-half of the pulse repetition frequency, or one-half your sampling rate is when the Nyquist limit is exceeded.

Pulse repetition frequency is determined primarily by the velocity scale. and it's limited by your imaging depth. So we can start to eliminate aliasing by increasing the velocity scale. You can also adjust the baseline. And if aliasing cannot be eliminated in normal pulse wave mode by maximizing the scale, we can switch to high pulse repetition frequency.

And what this does is it can increase the number of active sample volumes. So high pulse repetition frequency Doppler utilizes multiple sample volumes to increase the max maximum velocity that can be detected. And here we see the 2K.

And in this example, we'll have two pulses that are sent in succession from the transducer. So here's pulse one going to sample volume one. Here's pulse two. Now, as that first pulse is returning, it's going to overlap with the second pulse. And then these two pulses will reach the transducer at the same time.

So the ultrasound system cannot discern the depth of these overlapping pulses. And then that sets up our limitation for high pulse repetition frequency Doppler, which is range ambiguity. Because again, the system cannot tell from which step these returning echoes come when the pulses are overlapping.

With continuous wave Doppler, this is a technique in which the transducer is continuously sending pulses and receiving reflected red blood cell frequency shifts. There's no wait time, so there's no Nyquist limit. And because of that, the advantage of continuous wave Doppler is that it allows us to accurately measure high velocity. Now, the limitation is when we're constantly sending and constantly receiving along this line is that our high velocity could come from anywhere in this path. So with continuous wave Doppler, we cannot determine the precise location of the high velocity, and that's known as range ambiguity.

Next, we'll talk about Doppler tissue imaging. By definition, this is a technique used to measure the Doppler frequency shift of the moving myocardium and the annuli of the mitral and tricuspid valves. It's different than conventional pulse wave Doppler, which is used to assess blood flow velocity.

And that's because blood flow is high velocity and low amplitude signal. With Doppler tissue imaging, we're looking at the myocardium. And the myocardial Doppler signals are low velocity, usually less than 20 centimeters per second, and high amplitude, usually greater than 40 decibels.

Therefore, we need a different preset. And the Doppler tissue imaging preset should be set to optimize for low velocity, so a scale less than 25 centimeters per second or lower, and a higher amplitude. So we need to adjust the wall filter setting. And this is showing an example of where we see... see an optimized DTI preset where we're clearly seeing our E prime and A prime and S prime waveforms.

And what we're able to do is through adjusting the wall filter and our scale setting to be much lower, we can have accurate depiction of the myocardial Doppler. This is using the same patient, but using the standard setting for the pulse wave Doppler. And you can see this is an uninterpretable signal for measurement and looking at our myocardial Doppler. signal. Next, we'll talk about M-mode, and we'll talk about M-mode sweep speed, durable M-mode, and color M-mode.

By definition, this is an instrumentation setting used to optimize the timing of events in M-mode displays. The default is usually 100 millimeters per second. The effect on the image is that we can, through adjusting the sweep speed the same as Doppler, we can determine the number of cardiac cycles visualized. Faster sweep speeds of 100 millimeters per second are better for measurement.

Slower sweep speeds are better for certain physiologic conditions when, again, we want to see changes with time and we want to demonstrate more cardiac cycles. And this is just an example showing a sweep speed of 25 millimeters per second where we see more cardiac cycles and then as we switch it to 50 millimeters per second. Color M-mode can also be used, and by definition, this is an instrumentation setting that's used to integrate the color Doppler image with the M-mode tracing.

The benefits of this are that the timing of certain color flow events within the cardiac cycle can be better depicted. So we can really time the insufficiency jet. And we can also evaluate left ventricular inflow propagation velocity.

This is an example that shows a color M mode that assists with the timing of events. And the image on the left is demonstrating our grayscale M mode with mitral stenosis. The image on the right is showing the M mode with mitral stenosis and diastole.

And then our regurgitant jet demonstrated in systole. And again, you can appreciate the timing of events using color M mode. Steerable M-mode is another feature.

This is linear measurements are overestimated when obtained of likely to the structure of interest. So if you're using your standard M-mode and it's perpendicular to the structure, but if you have a tip tart or a tart that's off axis, they're not going to be accurate. So what steerable M-mode or anatomic M-mode does is it allows you to steer the M-mode cursor like we can with our Doppler cursor.

and it will align, then you can align it perpendicular to your structure of interest. The image, however, is created from a selective display of part of the 2D image. So when you use a cerebral N-mode or anatomic correction N-mode, your temporal and range resolution are no better than if you're using your 2D measurements and image parameters.

So now we're going to review some of our objectives, and then we'll open up for questions. But we'll start by talking about, this is an image. And you can see it's too dark.

It's too dark to discern really our myocardium. It's definitely difficult to see our endocardial and blood tissue interfaces. And so we know we need to correct. Now, another feature is I can tell you the dynamic range is 50 decibels. So if I see that on an image, what would be the best place to start with adjusting from an instrumentation perspective?

Because we know that... 70 to 75 decibels is a better dynamic range for cardiac imaging and depicting the myocardium, the non-compact and compact myocardium differences, and then also endocardial tissue borders. We would start by adjusting this.

Overall gain would adjust the overall brightness, but it's not going to change the number of gray shades that we have available to us. Time gain compensation, this image is pretty uniform right now. And if we switch to decolorization, again, it's not giving us any more shades of gray to work with, which is what the problem is with this image.

So this image, knowing that it's at 50 decibels dynamic range, would be the appropriate change to make first. Then you may need to adjust these other features. Next, which scanning maneuver is being demonstrated to center the LVOP? So this is our...

scanning movement that we're doing. We're staying in the same plane. It's a small motion.

And what we're doing is we are doing a maneuver with the transducer to center the LVOT and align it more perpendicular for measurement. And this maneuver would be the rocking maneuver. Next.

Which of the following could be adjusted to eliminate aliasing in this example? And our choices are increased Doppler gain. Well, that's not going to eliminate aliasing. That's just going to fill in our Doppler spectrum and make it look more noisy.

Increase the wall filter setting. We don't have a lot of clutter here along the baseline, and we don't have a wide black gap indicating that the wall filter is too high. Decrease the sample gate size. we can look at what our measurement is.

It's pretty narrow, so it's small. We know if we make it bigger, we would lose this window and make it look like turbulent flow when it isn't, perhaps. And then we can increase the velocity scale. And what we're doing with the velocity scale is we're increasing our pulse repetition frequency, and that's what's going to eliminate aliasing. Next, is this image optimized?

to evaluate mitral regurgitation. So you're looking at it. We see this large jet.

We look at our scale. It's set at 0.35, and that's too low. So this is not optimized to evaluate this jet.

When we adjust the scale to 0.62, we now can see adequate depiction of our mitral regurgitation. And now we have optimized our image. So to review, the pulse wave Doppler, the advantage we talked about was range resolution. Because we can set that gate at a specific depth, we know that we're sampling velocity information from that depth.

The limitation is aliasing. And again, aliasing will occur when we exceed one-half the pulse repetition frequency. Continuous wave Doppler, the advantage is that it can accurately measure high velocities. The limitation is range ambiguity. And what that means is because we have an interrogation line and we're sampling continuously all along that line and also receiving the reflected frequencies all along that line, we can't say for sure where that high velocity is. velocity comes along that line of interrogation.

So, that's known as range, which is another term for depth and ambiguity. So, we aren't sure of what depth that velocity is coming from. Thank you for your attention, and we'll now open it up for questions. And we'll start with, what would you say is the main three changes to this document from previous documents? And I guess to summarize it, I think the main thing is that we want to, what we really put in a lot of work in this document too were the how-tos.

So how to know if your instrumentation is set up correctly. We do really want to encourage people to meet with your application specialist too when you're setting your presets. Look at the different grayscale maps.

Look at the patient population that you have coming in. And then we also wanted to offer just some scanning tips. Next, there's a question about, there seems to be difficulty in understanding the difference between tilting, rocking, and angling. How can we distinguish clearly between these maneuvers?

And this was another struggle we had as a writing group. And there was a document existing from the American Institute of Ultrasound and Medicine, and that's really where we used then their definition of tilting. And I'm going to go back to the slide for just a second here. And what our hope with kind of putting this together and starting to use the same terms across disciplines, such as what the AIUM already was using, what was already available in some of the ECHO textbooks, is to start to use the same terms.

So tilting, we're referring to your kind of fixing your transducer, and then you're going to change the plane that you are cutting through. Rotating, everyone kind of uses that very similar. And again, that's just rotating, keeping your transducer fixed and just rotating the orientation index.

Sliding is also standard. Rocking and angling, angling also was another one that was pretty standard as far as kind of directing the beam towards your structure of interest. And then rocking, again, we used with looking at the AIUM literature and also what had been doing. published in the ECHO literature previously to discern those maneuvers. So rocking is just a small maneuver that you're using to center a structure and you're staying in the same image plane.

Tilting, you're going through other planes. Next, there's a question, what is the recommended pulse wave sample volume for spectral Doppler velocity and tissue Doppler? And what I guess we're looking at is you'd want to work with your application specialist to design a preset. One of the things that we're looking at here is that you for sure want to have a lower velocity scale set below less than 25 centimeters per second.

Your wall filter should be set for high amplitude signals, again, greater than 40 decibels. And then also, sorry, looking at the question here again, you use a larger volume samples than what you do with your pulse wave Doppler. Another question is, are there any rules about what color scale setting we should use?

And it's recommended to start with 50 to 70 centimeters per second. Another question was posed regarding rocking and angling. Are they the same or what is the difference? Again, rocking is staying in the same plane and your goal is to center the structure. Angling is you're directing the beam so you are directing it towards focusing in on, in this case, the best example is really looking at your tricuspid valve and then angling.

more leftward in this case to look at the pulmonic valve. Do you find over-measuring spectral Doppler waveforms by not measuring the modal velocity? I think one of the things that's important to do when you're looking at and for the modal velocity is to make sure that your gain settings are set accurately. And if you are using pulse wave Doppler and you believe the flow is laminar, you should see that window.

And if you're not seeing that window, you may be over-gained. You may have a sample volume. that's too large, those would be things to start with. Another question, can you review the difference between gain, dynamic range, and grayscale maps again? So what grayscale maps are showing us is this is how we're going to display the brightness of the amplitude signals returning.

And we can choose to kind of suppress and enhance different... signals in different ways. It's not changing the number of shades of gray, though.

It's changing how we choose to display them and what brightness we want to display them at. For dynamic range, what we're actually doing is we are determining the number of grayscale values that we want to use. So the number of shades of gray. So they are different.

This is... brightness level on your monitor, how you're going to see it. This is determining the actual number of grayscale values you're going to use.

Again, there's more questions. The peristernal long axis, could you review the peristernal long axis technique as another question? So typically, you're going to... start with your orientation marker on the patients in the left lateral decube as long as they can move the orientation marker should be directed towards the patient's right shoulder we're cutting along the long axis of the heart and what we're looking to identify is you want to kind of have your left ventricle your septum stretched out here we want to be perpendicular to the structures the structures that are viewed in our starting image are the left atrium the micro valve the left ventricle, the left ventricular outflow tract, aortic valve, ascending aorta, and the right ventricle.

And there's another question, is 100 millimeters per second the speed recommend for all measurements? And yes, that is the recommendation for all our Doppler and M-mode measurements. However, again, depending on the patient's heart rate, you may need to adjust that. It's ideal to really show... two to three cardiac cycles, that's going to help you with just looking at measuring time intervals.

However, if you need to get a good measurement, you still want to be able to spread out your Doppler signal or your M-mode, and that will make it easier to have an accurate measurement. There's another question. How is grayscale different than gain? Gain is just adjusted the overall brightness of the echoes as they return.

So as all of the echoes return back to the transducer and ultrasound system, gain is going to uniformly, however you have that set, amplify all of those echoes across your entire image. Gray scale is we actually are choosing, based on a post-processing map, how when those signals come back, what brightness we're going to give them. And that's based on the gray scale map.

that you choose. So it's not going to uniformly increase them. It's not something that the user is doing real time. It's something you can adjust based on, again, what map you pick. And again, it's going to be how you display all of those amplitude signals as they come back to the system, not amplifying them all uniformly.

So, one of the things, there's a question about ultrasound systems used for the presentation. And we did use multiple different systems for both the guideline document and putting together the images for this presentation. It is important to note that, you know, while all systems have these controls and these instrumentation settings, they may have slightly different names.

And I guess, you know... We didn't specifically write protocols per machine for the guideline document nor the webinar. And what we would do is we would encourage, based on this information and, you know, how you want to set your presets based on a grayscale map that will help you discern your endocardial tissue borders best.

differentiate between the compact and non-compact myocardium. We would want you to work with your application specialist to go through those post-processing or grayscale maps with you and help you discern based on your patient population what would be the best one to give you that information. The same is true. We would want you to set your sweep speeds at 100 millimeters per second or to know that's the recommended guideline. And again, to work with the application specialist so you can optimize your own system that you're using to kind of match the criteria that we stated in the guidelines as close as possible.

But because each system calls to control something slightly different, we didn't go through and list out kind of official presets for each piece of equipment that could be used. And also... Just people may have different makes and models of equipment and different software versions as well.

And I think we have concluded our time here. Well, thank you, everyone, again, for your attention and time today.

Transcript for:Comprehensive Echocardiography Guidelines Overview

Transcript for:
Comprehensive Echocardiography Guidelines Overview