Welcome to ASGE Endo Hangout for GI Fellows. These webinars feature expert physicians in their field, and I am very excited for today's presentation. The American Society of Gastrointestinal Endoscopy appreciates your participation in tonight's event, Optical Diagnosis. My name is Michael Dellutri, and I will be your facilitator for this presentation. Before we get started, just a few housekeeping items. We want to make this session interactive, so feel free to ask questions at any time by clicking the Q&A feature on the bottom of your screen. Once you click on that feature, you can type in your question and hit return to submit the message. Please note that this presentation is being recorded and will be posted to GILeap, ASGE's online learning platform. You will have ongoing access to the recording in GILeap as part of your registration. And now it is my pleasure to introduce our GI Fellow moderator, Rashad Khan, from the University of Toronto. I will now hand over this presentation to him. Thanks, Michael. Hi, everyone. Thanks for coming. I'm Rashad, a Gastroenterology Fellow at the University of Toronto and today's training moderator. So we've got a great session with Rob Bachara today, and I'm sure many of you have seen some of his sessions in the past. So Dr. Bachara completed his GI training at Queen's University and advanced endoscopy at St. Michael's Hospital in Toronto, and went on to do an additional year training in magnifying endoscopy, optical diagnosis and third space endoscopy at Showa University in Japan. He's since come back to Queen's University where he's an associate professor and has built up one of the largest ESD and poem programs in North America. I'll now hand it over to Rob. All right. Thanks, Rashad. And thanks to the ASGE for inviting me to do this talk. So today we'll be talking about endoscopic examination of colorectal polyps. I see we have a number of some of our Canadian trainees here. So thanks, everyone, for joining. So we'll get started. So these are my disclosures. And I'll just draw your attention. I'll ask you guys to kind of to log on here to poll everywhere because we'll be doing some polls in a few minutes. In terms of the objectives, I'm going to introduce the macroscopic and microscopic exam of colorectal polyps, some high gross or high risk gross morphologic features of colorectal polyps, and just being able to apply the NICE classification and the JNET classification and some of the advantages of JNET. So first, we're going to go over some cases, the macroscopic exam, the microscopic exam, and then we'll go back to the cases. We have a few extra cases depending on time. So hopefully you guys have had a chance to kind of go to poll everywhere. So the first poll is how familiar how familiar are you guys with the Paris classification? So you use it all the time confidently somewhat. You kind of have to look it up, but you do use it sometimes minimally. You know what is it? You know what it is, but not how to use it. And otherwise, what is the Paris classification? So about 50% seem to use it fairly frequently, you know, regularly, and then it's kind of split up with the rest. So that's good. And how about the laterally spreading tumor classification? Are you guys familiar with it and use it regularly, somewhat, minimally, or not at all? So a bit more variability with this one than than the last one. And how about the NICE classification? So very confident with it, somewhat, minimally, or not at all. So kind of expected. Most people seem to be relatively familiar with the NICE classification, so that's good. And then finally, the JNIC classification. So the Japan NBI expert team classification. So this one as well, there's a bit more diversity in the experience with it. So that's good. So we'll be going over that as well. OK, so we'll start with the case. First case, a FIT positive patient. You kind of did your colonoscopy, you're coming back, you're retroflexing, and you see this lesion here in the rectum. So you examine it initially with white light and depending on your platforms, your various image enhanced modalities. This is LCI, so linked color imaging, which basically highlights the difference between the spectrum of red a bit more so than regular light. And then this is BLI, so equivalent to NBI. That highlights the vasculature and the surface. They use a little bit of magnification to get a closer look at the lesion. This is in forward view. Again, get a good examination, use your various image enhanced modalities and a little bit of magnification to be a bit more confident in terms of what you're seeing. OK, so. Now, here are the some images of the lesion. So if you had to guess the pathology, is this kind of low grade dysplasia, high grade to superficial submucosal carcinoma or deeply invasive carcinoma? So get a good look at the images, kind of make your decision, and then we'll see in the polls. What did you guys think it was? All right, so everyone thinks it's low grade dysplasia. That's good. So maybe you guys don't need most of this talk. Let's see the other cases if you guys are all equally as confident. So, this is a case of a patient who was also fit positive and found to have a rectal polyp. And basically sent for assessment. So, same kind of approach, you're going to do your macroscopic exam. So this is white light. So you can see a fairly extensive polyp. We started looking at it a bit more closely, again with white light, just to get a rough idea in terms of the extent of the polyp. So in a minute, we're going to start switching to our image enhanced modalities. You're going to move close to the polyp. And again, try to get a bit more detail in terms of what you're seeing in terms of the surface and the vasculature. The other thing you'll notice that I'm doing when I'm examining it, I'm suctioning and insufflating, just to see how pliable it is so you can get an idea how well it moves with the wall. So again, that's a very coarse way of examining things just to see, is this something that's potentially deeper or is it more superficial? So generally do that when you're examining lesions, again, seeing what happens when you suction and what happens when you insufflate. And then again, now I'm examining with LCI. You can see I'm going around the margins. So you can see it has a bit of a more bulky area in the center. And then there's a skirt, which you don't really appreciate if you examine it from very far away. And then when you go closely with image enhanced endoscopy, you can see that kind of slightly elevated flat area along the margins. So after switching from LCI, we're going to switch to BLI, which I'll kind of just skip forward in a second here. So that's BLI. And again, now I'm starting to examine the bulky areas in a bit more detail. And we basically do this around the entire lesion. So you do your kind of examination in a systematic way using all your image enhanced modalities in addition to magnification. Just kind of moving up here again, looking at the surface, looking at the vasculature, seeing if there's anything that gives you clues in terms of the various pathologies in the different areas. So this is the lesion here. So again, is this just low grade dysplasia, high grade to superficial carcinoma, or is it a deeply invasive carcinoma? So let's see what you guys think. So a bit more variability, about 30% low grade dysplasia, about 70% high grade to SM1, and nobody thinks it's deeply invasive carcinoma. All right. So let's move on to the next case. Again, this is another lesion in the rectum. And again, systematic examination. So when you see something, examine it the same way every time. Clean things very well, suction out your water, and then look at the lesion from far away. Get a rough idea of kind of the morphology, then move closer. Use all your image enhanced modalities. Each one will highlight different things. And every so often one will help you notice something you may have not noticed with the other. Now you move in with magnification. And then we start looking at things again in a bit more detail, looking at the vascular and the surface structures throughout the lesion. So here are the gross pictures. And here are some of the magnifying BLI pictures. So let's see for this one. Do you guys think it's low grade, high grade to superficial carcinoma, or deeply invasive? So, okay. So, again, fair spread. Again, nobody thinks this is low grade dysplasia, so that's good. And then kind of split between high grade to SM1 and deeply invasive carcinoma. So we'll move on to the Paris classification. So I think most people were familiar with it and use it, but there's some people that were not. So it's basically just a macroscopic description of pulps. It was initially in 2003 that it was introduced. It was an international kind of conference from people around the world, including pathologists, surgeons, oncologists. And it was really to discuss the Japanese classification that's been around for years prior and its application in the GI tract for superficial neoplasia. So you basically have three kind of main categories. Your protruding type, your flat type, and your excavated. So protruding, when we're talking about columnar mucosa, which the colon is, basically anything greater than 2.5 millimeters is, you can estimate that with your biopsy forceps, but again, you can, again, visually estimate, but greater than 2.5 is 1S. And then you have your 1P, so your pedunculated pulps that have a neck, and then your flat pulps. So you have your slightly depressed pulps, so 2C or 2C components, so 0.5 millimeters or less. And then your 2B lesions, so completely flat. And then your 2A lesions that are slightly elevated, so less than 2.5 millimeters elevation. And then excavated lesions, we generally don't see in superficial colorectal neoplasia. You can see these for others. So in terms of gastric and esophageal, sometimes you can have excavated lesions that are superficial, but generally for colorectal, once it's excavated, they're generally deeply invasive lesions. And the macroscopic assessment using Paris classification, again, gives you a rough estimation of the final pathology. So this is kind of what people already know. You know, a depressed lesion generally has a higher risk of subucosal invasive carcinoma. So even when they're smaller, you can see that there's a fair risk. This is from a series in Japan of about 20,000 lesions. So you can see as lesions get bigger, as well, the risk of subucosal carcinoma increases. And then over here, it shows you again for elevated lesions, so 2A, 2B, or 1 lesions. Again, as they get bigger, the risk of subucosal invasive carcinoma goes up. So we'll move on to the LST classification, which I think not everyone is familiar with, but it's an extremely useful classification because you can get a lot of information just from the gross examination. And the important thing to know about the laterally spreading tumor classification is that you can't apply it to every single lesion. And if you read a lot, unfortunately, a lot of publications, it's often used incorrectly, and it's not noted in some of the publications. So it has to be a lesion that's predominantly growing horizontally. So meaning predominantly 2A, 2B, or 2C lesion. So if it's a 1S lesion, almost all of it, and it's just one small area that's slightly, you know, 2A or 2B or 2C, it's not an LST. So these big protuberant lesions in the colon that are mostly 1S are not LSTs, and you cannot use the LST classification on them because it's not valid. So you have four main categories. Your LSTG homogenous, so kind of lumpy, bumpy, all looks fairly similar. Your LSTG, so granular mixed type. So the lesion mostly is like this, but then you'll have at least one of these dominant nodules. And your non-granular flat, so just kind of smooth, flat lesion as you see here. And then your non-granular pseudodepressed. So again, looks like this in terms of the surface morphology. So we'll have a slight depression. So what can you get from that information? So just from that, you can get a rough estimate in terms of, again, the risk of submucosal carcinoma. Granular homogenous, generally very low risk. Granular mixed, intermediate. The non-granular flat are also intermediate. And then the non-granular pseudodepressed generally have a high risk of submucosal invasive carcinoma. And again, it varies on the size depending on your series that you read, but it's a good thing to know kind of a rough estimate. So low, intermediate, and high based on the gross morphology. The other thing that's really useful is, again, gives you an idea in terms of the fibrosis. Generally, the granular homogenous, low risk of fibrosis. They lift very well. You remove them fairly easily, even when they're larger. The granular mix is kind of intermediate, as are the non-granular flats. The non-granular pseudodepressed generally have a fair bit of fibrosis, and usually submucosal fat as well. The other thing that correlates is the lift. So these lift very well. These lift fairly well. These are, you know, okay, and these don't lift well at all when you inject them. And this kind of correlates with resection difficulty. So this is why you have the issue with lifting of these lesions. So actually, I'll show you that in a minute. The other thing about these lesions, when they have carcinoma, so the granular mixed, when they have submucosally invasive carcinoma, you can see that about 80% of the ones that have carcinoma in them are deeply invasive. And then the non-granular flat and the non-granular pseudodepressed, when they do have carcinoma, about 50% are deeply invasive out of this series. So this is what I was just about to tell you guys in terms of why the lesions lift well, and the granular ones lift well, and the non-granular don't. So this is just showing you the red is the muscular smucosa. So this is kind of an electronic measurement tool that they have. So you could see how it goes up and down. And then the green is basically the lesion measurement. So basically, the muscular smucosa is much longer than the lesion. So when you inject it, it has a lot of ability to lift up. So the lesion lifts very nicely. So the non-granular lesions, the muscular smucosa and the lesion are almost exactly the same size or length. So when you inject submucosally in these non-granular lesions, they don't lift up very well, like the non-granular or the granular type lesions. So they just lift very diffusely. And these are the ones where people lift them, you put a snare over it, and it keeps sliding and, you know, you end up butchering it, unfortunately. So that's why these ones end up being difficult when you over-inject them. Whereas these, you can inject a lot and they lift very well. They're nice and easy and enjoyable to remove via EMR. And this just kind of shows you that there. So again, you see the muscular smucosa. And then when you inject it, it does not lift particularly well. Whereas these granular lesions with the wavy muscular smucosa, you lift it. And again, you get a great lift and resection is nice and easy for the most part. So traditionally, this is kind of what's been taught in terms of colorectal adenocarcinoma and endoscopic resection. So things grow vertically. So M1 is epithelial carcinoma, lamina propria, M2, then muscular smucosa, and then SM1, SM2, SM3. So that's just kind of traditionally what we've been taught. So the risk of carcinoma or lymph node metastasis from mucosal carcinoma to superficial carcinoma is fairly low, about 3%. So generally indicated for endoscopic resection. So SM2, a bit of a higher risk, and SM3, even higher. And generally, those are usually referred for surgical resection if you find that in your resection specimen. So however, over the years, more and more studies have come out that took into account the tumor characteristics. So differentiation, lymphovascular invasion, tumor budding. The older studies didn't account for those. They basically just looked at the depth of submucosal invasion but didn't correct for those other variables. So these studies and others have come out where they correct for those variables. The risk of lymph node metastasis is actually much lower than expected, even with deep submucosal invasion. And then most recently, Dr. Decker's group came out with this meta-analysis and indeed showed that deep submucosal invasion as a solitary risk factor is not really significant for lymph node metastasis. And even with deep invasion, the risk of lymph node metastasis was overall quite low. So I think in the future, in the not too distant future, you're probably going to see expansion of the indications for endoscopic resection and the definition of curative resections. So we'll move on. And this is a practice lesion. So if you had to guess, is this an LSTG homogenous? Is this a mixed type? Is it non-granular? Or is it a non-granular with pseudodepression? So please use your polls. Okay. So most will say LSTG mixed. Some say homogenous. So it was actually an LSTG mixed type. So if you just look here, you can see that there's, you know, this big nodule here, where it's over here, there's all these little tiny, you know, regular bumps and nodules. So if it was all like this area here, it would be LSTG homogenous. But sorry, but because you have at least one of these nodules, which you can see, it's an LSTG mixed type. So just based on the gross exam, guess it has an intermediate risk of submucosal invasion. And this lesion ended up being just tubular villus adenoma with high grade dysplasia. So another lesion. So this was actually in the cecum. So if you had to choose granular homogenous, granular mixed, non-granular flat, or non-granular pseudodepressed. So I'll try to magnify some of it for you here, get a bit of a better look. Before you guys make your decision. So, okay. So this one, again, not super easy. This is about, you know, 60 or 70, 30 between pseudodepressed and flat. So this was actually a LSTNG pseudodepressed. So you can kind of appreciate here, if you look at this fold, then there's this very, this depression right here in the lesion. And again, you can kind of appreciate it here as well, looking at just the contour here. So it was an LSTG or LSTNG pseudodepressed. And this ended up being an SM1 carcinoma. And this is just the little area of carcinoma here. This is the muscular smucosa right there. You see this little small area going right past the muscular smucosa. So it was a superficial carcinoma, sub-mucosally invasive, but good margins, less than a thousand micrometers, a curative resection for this patient. All right. So we're going to move on to the high risk of gross morphology. So still part of your gross examination. So these are some things that give you a hint that the pathology might be more advanced. So fold convergence, demarcated depressed area, stock and base swelling, spontaneous bleeding, and something called chicken skin mucosa, or these white spots. So this is fold convergence. So basically here you see one fold, two folds, three folds, and all of them converge right here. And again, here you see two. There's another one on the other side, but you can see how they converge at the lesion. So that's usually indicative of invasive carcinoma. This was a sub-mucosally invasive, deeply invasive carcinoma. And here as well, you see the same thing. One, two, and three folds. You can't see on this side, but this was also a depressed lesion, but you can see three folds coming together and fusing. So this was actually a T3 cancer in the sigmoid colon. So demarcated depressed area. So you can see this lesion is elevated and has a depression in the middle. And within that depression, there's an area of demarcation of this depressed area. And that again is usually indicative of more advanced neoplasia. This was an SM3 lesion with lymphovascular invasion. This lesion here on the right is that same lesion we just saw on the last slide. This one, but just with a little bit of indigo carmine. So it had the fold convergence, but also again, a demarcated depressed area. Hopefully you can see my pointer. So right here. So again, another high risk feature indicative of more advanced neoplasia. So stock or base swelling. So this you can see is kind of a pseudo pedunculated lesion and just this very engorged big stock. This was a vasculine invasive carcinoma. And this you can see is again, a lesion with this base swelling. And this was a SM2 carcinoma that also had lymphovascular invasion, interestingly enough. And it was probably about a centimeter or so. Spontaneous bleeding, pretty self-explanatory. This was a rectal lesion, and this is just going in and washing. So just as with washing, spontaneously bleeding. So again, intuitive, more indicative of invasive carcinoma. So this was a mucinous adenocarcinoma with deep subucosal invasion, and he had two positive lymph nodes. And this is called the chicken skin appearance, which you can see here. And basically, it's intra, not intraepithelial, but lipid-laden macrophages in the lamina propria. And you can see, gives you kind of this whitish appearance. So there's something else that you can have, again, lipid associated with something like this. So this is a lipid-laden macrophage. Again, lipid associated with something called white opaque substance, kind of an aside, but it's different from this. White opaque substance is lipid deposited in the epithelium. And when you have the white opaque substance in the epithelium, you basically can't see any of the vessels. So sometimes you can see that with some colorectal, some upper GI pathology, but that's kind of as an aside. But there are two different things. The location of the lipid is different. So this was a rectal lesion, and this ended up being just high-grade dysplasia. But again, you can see the chicken skin mucosa here, and here again, a bit more closely. So then you'll say, well, I have all these gross things I can look at endoscopically. Why do I need image-enhanced modalities? Why do I need to use magnification? So this is a study, a systematic review that included over 30,000 lesions, and basically looked at the use of gross morphologic features and magnifying endoscopy. And if you just use the gross features, the accuracy is much lower than using image-enhanced modalities such as NBI, BLI, and or magnifying chromoendoscopy in predicting invasive carcinoma. So basically, it means, you know, when you're doing your examination, again, kind of reinforces why you do it systematically, why you first do a macroscopic exam, then your more detailed magnifying exam, because you're looking for these high-risk features. And if you see any of these high-risk gross features, take a bit more time and a bit more careful exam doing kind of a more detailed magnifying close exam. So that's the important kind of take home from this study. So now we're going to move on to the microscopic assessment. So in terms of pit pattern, NICE, and JNET. So probably the oldest kind of magnifying or microscopic examination is the ACUDO classification. And again, this is one of those things that's often used and discussed completely incorrectly in papers and in, you know, in academia. So hopefully, this will give you a good understanding of it. So we're going to come back to the details of it. But basically, this is the pit. And when we talk about pit patterns, this is kind of what we're talking about. And this is just showing, pretending this is indigo carmine. Excuse me, this is crystal violet. But I'll kind of show you guys exactly what it looks like in a second. So the classification, again, there's a bit more subclassifications to it, but these are the main ones. So type one and type two, basically normal mucosa or hyperplastic or serrated lesions. So this is with crystal violet. And crystal violet is going to stain the epithelium purple, which you can see here, and in the middle kind of stays unstained and kind of looks pinkish. This is normal colonic mucosa. Here, again, you can see the epithelium is stained pink with crystal violet or stained violet. And in the middle, you have this kind of stellate area that's not stained. And that's typical of hyperplastic and serrated lesions. Then you have your adenoma, so 3L and 4. Generally, 4 correlates to tubulovilous adenoma, but just a simplified adenoma. 3L, again, you can see this long, L is for long, so kind of this long pit. Again, unstained pink in the middle. And then 4 looks kind of like a brain, so like a gyrus. That's a type 4 tubulovilous adenoma, generally the correlation. And then 3S and 5I generally correlate with high grade and superficial carcinoma, which you can see here. So again, a bit more irregular in its appearance in terms of the pits, 3S versus 5I. Overall, the accuracy is probably the best for any optical diagnosis classification using pit pattern. 5N is deeply invasive, and it's basically amorphous. You actually can't see any pits. So there's complete loss of the pit pattern. That's indicative of a deeply invasive carcinoma. And that accuracy, again, in terms of predicting deeply invasive carcinoma is quite good at 95%. So that was kind of the main classification for many, many years, and then NBI came along. And now we're going to go into kind of the classifications that were based on NBI. So NBI, when it first came out, and now all the subsequent platforms that use very similar technologies, basically used certain wavelengths of light. So NBI, when it first came out, they used 415 and 540. And that's because those are the wavelengths that are most readily absorbed by hemoglobin. So here, this shows you what happens with the 415 wavelength. So 415, so basically, you get absorption by the capillaries, it's a relatively low energy wavelength. So it gets absorbed by the capillaries. And then otherwise, most of it is scattered. And the superficial capillaries look very dark. So they appear like almost a brownish or very dark color. Then 540 is the other wavelength that's used. So it's a higher energy wavelength. And you'll get some absorption by the superficial capillaries, they appear kind of in a lower contrast grayish appearance. And then because it's higher energy, it's absorbed more deeply by the venules, which are deeper in the mucosa. And those appear quite dark and in good contrast. So that's kind of NBI. And this again, is another schematic kind of showing you 415. This is of the same area. So the roof of a patient's mouth, 415 wavelength, you see all these tiny capillaries, 540, you can see the venules. And then this is a deeper wavelength, which again, you don't, we don't typically use or is available. But this is just kind of prototype at the time, but showing you that basically the deeper veins are highlighted. So this is all the exact same area, and just showing you how the different wavelengths highlight different areas of the microvascular structures in the mucosa. And why do they call it narrow band imaging? So the normal wavelengths of light, basically, if you kind of filter things out, you're going to get this normal kind of bell curve type distribution of the wavelengths. So 415 is right here. And then basically, when they filter out all the superfluous wavelengths, or as much as they can, they basically get a narrower, closer to true 415 wavelength, and that gives you a higher contrast. So that was with kind of the older endoscopes where they use the Xeon lamps. Now, pretty much all the platforms use LEDs. So they're a bit easier in terms of filtering out the different wavelengths because just the way the technology is, they don't have to use an optical filter, they can basically decide what wavelengths they want with the LEDs just much more easily, and it's generally much cheaper than kind of with the older platforms. So with NBI, then came all these classifications that looked at the microvasculature of the colorectal polyps. So you had the first one was the Sano classification, then the GK classification, Hiroshima, Showa, and there's been others. So it became quite complex in terms of all these different classifications. And as a result of that, they basically decided to kind of amalgamate things and come up with a much simpler classification called the NICE classification, which most of you seem to be aware of. And it's been around now for quite some time. And I think, for the most part, is in your kind of curriculum, and you're all familiar with it. So I'm not going to go into too much detail with it. But very briefly, you know, the type ones you kind of know, in terms of the overall gross exam, they're going to be lighter than the background, or the same. And in terms of the vascular structure, you may not see any vessels at all, or some isolated kind of lacy vessels, usually with serrated lesions. And then in terms of the surface pattern, you'll see the kind of dark spots or white spots, as you can see here. Type two, the typical adenoma, in terms of the surface structure, you're going to see a regular repeating epithelium, which is the white parts. And in terms of the dark structures, regular repeating pattern as well with kind of a meshed or branched structure, and the vessels generally having the same calibers and distribution throughout the lesion. Then type three, again, everything is all irregular. So in terms of the surface, you may not even see a surface pattern, it may be completely obliterated. And the vascular pattern, you may see hypervascular areas, avascular areas, large neoplastic vessels, varying calibers. And that's your your nice three. So a nice, simple, easy to remember classification. So let's practice that. So this is an example of a lesion in the ascending colon. Here are some images. But again, your examination using white light, again, doing a gross examination, and then you're going to switch with your image enhanced modalities between the different ones. And then move more closely, a bit of magnification, kind of examine through, you know, the entire lesion, and see kind of what things look like in terms of the surface and the vascular structure. So what do you guys think this lesion is? Is it nice one, nice two, or nice three? Here's a representative image. Good. So everyone is in agreement. It's a nice two. This is indeed what it was. It was a typical tubular adenoma. So just for interest sake, how about the pit pattern? So pit pattern here, I'm using indigo carmine. So is this 3L, 3S, type 4, or 5I pit pattern? Good. So everyone got that as well. So this is kind of looks like a brain. So you can just look at it. You can imagine, yeah, this might actually be a brain. So if you see that it's going to be a type 4 pit pattern, generally low grade dysplasia, tubular villus adenoma. Okay, and how about this lesion? So this is just the NBI image, grossly, and then with a bit of magnification. What would you guys say that lesion is? Good. So everyone thinks it's a nice one. Some say it's a nice two. I may have given it away, but it's a nice one lesion. This was in the rectal sigmoid. So you don't actually see vessels. You see these dark spots, but you don't actually see any vessels. It's lighter than the background. So this is your typical hyperplastic problem. Okay. How about this lesion? So this is in the rectum. So again, systematic exam, gross white light, in this case, LCI, BLI, again, grossly, move more closely, a little bit of magnification. And then when you magnify your lesions, whether it's near focus or formal magnification, again, I would say focus on looking at one area first. So say I'm just going to look at the dark areas. So meaning the vascular structure. So I'm going to focus on the vessels. So look at the vessels, don't look at anything else, and then see what you see. Is it a regular repeating pattern? Is there some degree of variability? Is there complete irregularity in terms of large vessels, small vessels, avascular areas? And then after you've examined everything and looked at the vessels, then look at the white part in terms of the surface. Do it systematically. It will be very easy after you get to do it over and over and over, and you're less likely to kind of miss things or misinterpret things. So, and here we are with a bit of magnification and examining things closely. And there with a bit of high magnification. So, if you guys had to guess, is this a nice one, nice two lesion or nice three lesion? Okay, so everyone thinks it's a nice three lesion. So, I agree. So you can see in terms of there's areas where the surface is completely lost. And again, in terms of the vascular structure as well, again, some areas where you can't even see any vessels. So this actually ended up being a SM3 carcinoma with poor differentiation in LVI in a very comorbid patient who could not undergo any surgical resection and was removed endoscopically with ESD. And yeah, years later, he didn't have any kind of recurrent disease, but ended up dying from pulmonary disease, which was his severe comorbidity. So you're like, well, nice is great. Why don't we just use that? So overall, it works reasonably well. But if you look at the details of the studies, the vast majority of them did not include larger polyps. So they kind of enriched the population to make the data or the operating characteristics of it quite good. So most of them were one centimeter or less polyps. They didn't include high grade in SM1. So it was basically all hyperplastic, all adenomas and all deeply invasive. So again, making it very easy to use a nice classification. However, when you start getting lesions with high grade in SM1, the operating characteristics of it are not as good as they were for those studies where they kind of again, enriched it to have a good outcomes. And when you started getting these larger lesions and variability in pathology, you can see the diagnostic confidence dropped, the accuracy dropped. And again, you can't predict high grade to SM1, which again, clinically is very important. The other thing is you can distinguish between hyperplastic and SSLs with that classification as well. So as a result of some of the shortcomings of JNET, or sorry, NICE, JNET was introduced. JNET basically broke down 2 into 2A, which was low grade dysplasia and 2B. And 2B is more indicative of high grade to SM1. There is also a sub classification of 2B, which was 2B high and 2B low that was also introduced, but it's operating characteristics weren't great. So generally it hasn't been practiced in terms of, or applied to the 2B high and 2B low. So this is what it looks like. So JNET or NICE 2, then you have your JNET 2A and JNET 2B. So your JNET 2A in terms of the microvasculature, you're gonna have a regular caliber of the vessels and the distribution is gonna be uniform throughout it. The surface, so the white part, again, regular width and distribution throughout the lesion and the predicted pathology is generally low grade dysplasia. So 2B lesions, you start seeing variability in the caliber and the distribution in terms of the microvasculature. And then again, variability in the width and distribution of the white part. And in some areas you may even see obscure absence surface with JNET 2B. The predicted pathology is generally high grade to SM1 carcinoma for 2B. So again, this shows you the JNET classification. And these are the kind of two that are different really, are different from the NICE classification. This is a short video showing you again, a lesion with magnification. And this was out of a video from Dr. Saito's group. So it shows you quite nicely in terms of the difference between JNET 2A, so this periphery regular distribution of the vasculature, regular caliber, and then the white part. So again, you can see the epithelium, nice kind of regular widths. And then as you go in here, there's variability in those things in terms of the microvasculature and microsurface. So really nice video demonstrating the difference between 2A and 2B. So the advantages of JNET, improved overall confidence because it requires a magnification, the ability to distinguish between low grade, high grade SM1 versus deeply invasive. So here I also have advantages being utilized as magnification and also drawbacks. So this was traditionally what was said about JNET. Oh, you have to have magnification and we don't have it here in North America. That was always kind of like an excuse. But I think in 2024, there's really no excuse. And I think all the manufacturers have magnification and there's really, I don't think we have that excuse anymore to say why we do poor diagnostic examinations at this time. So in 2024, we don't have an excuse. We should have access to magnification. And I think it's an indispensable tool for us. And one of the issues though with the JNET classification, JNET 2B in terms of its overall accuracy in predicting high grade to SM1 is only about 80%. So what's typically done or recommended in Japan is if you have a JNET 2B lesion, basically you should use crystal violet and do a pit pattern analysis to improve the overall accuracy of your prediction. And for the most part, crystal violet's very hard to come by in North America. And generally, if you're gonna do a pit pattern analysis, indigo carmine works very well for pit patterns kind of one to four, but for five, so looking at 5i, 5n, you generally need crystal violet to do a proper pit pattern examination and properly predict things. So that's some of the challenges we have in North America. So now we'll go into some details about the pit pattern and what it is and what it isn't. So this is the columnar mucosa. So when you use indigo carmine, it pools in the pit and you see it like this, right? You can appreciate that. So that is the pit and that's what indigo carmine highlights. This is what crystal violet stains and the middle is unstained and I'll show you that in a minute. And then these vessels, so just underneath the epithelium in this area here is what you see with NBI and you can see that here. So this is with NBI and you can see that or a BLI NBI, you can see that with this arrow, that's pointing to the pit. You can't really see it very well with NBI, but NBI does highlight the vasculature and the surface very well. So NBI, BLI, optical enhancement with Pentax, those are not for pit pattern analysis and you can't accurately talk about pit pattern using those. And again, looking here with white light, the vessels are in the middle, the pit is here and then the white epithelium. And this area is called the intervening part if you read it in some of the literature. So, and this is in the middle of the intervening part is where you see the vessels. So here's, again, from pit to pit is the intervening part and in between you're gonna see surface, vessels, surface, and then the pit. And this white part, so this epithelium all along here, that's what you see again here with NBI. So the areas just around the vessels, that's kind of that epithelium that's going down. So here, so the white part and then the vessels in the middle. So white part, vessel in the middle, white part, pit. And here's, again, crystal violet. So remember crystal violet stains this part, so it appears purple. And this part in the middle, the pit stays unstained. So this is type four, right? And here, this is the epithelium. Right in the middle, you can kind of see the vessel. Again, you can't really see it very well with indigo chromium, that's because that's not what it's used for. And again, epithelium and then pit. And again, here's the pit here. So this kind of shows you the relationship between NBI and pit pattern analysis and why NBI, BLI are not for pit pattern examination. And you cannot comment accurately on pit pattern when you use those. Although it's very commonly done, it's completely wrong. So I hope this kind of explains what pit pattern is, what it is and what it isn't. So all this stuff to say like, well, why do we care about optical diagnosis? This again was a study out of Evelyn Decker's group in the Netherlands. So 3,622 colonoscopies, 92 T1 colon cancers were diagnosed. So of the 39% that were correctly recognized as cancer, only 11% went on to require surgical resection. 61% that were not recognized as cancer, a lot more people went on to have surgical resection. And 60% of the time, that was due to piecemeal removal of cancers. But basically this just says that, well, optical diagnosis is important because it allows us to make or allows us to give patients the most appropriate treatment and to not over-treat them. So not to send patients unnecessarily to surgery. So that's why optical diagnosis is important. So this is our experience using J-Net. So among lesions classified as J-Net 2B, overall accuracy of predicting high-grade to SM1, again, ended up being about 80%, thankfully. And roughly about 10% end up being low-grade dysplasia and about 10% end up being deeper, which you can see here. So for the most part, 80% you're gonna treat appropriately with on-block resection. About 10%, again, you're gonna maybe under-treat, but those patients can still go on to have surgery. And then another maybe 10%, perhaps you'll say, well, probably would have been just as good to do at EMR unless it's a rectal lesion. So this is our experience with J-Net, which has been pretty similar to the Japanese experience as well. So you can see why for J-Net 2B, ideally, if we did crystal violet, we could probably improve this and probably decrease this number and decrease this number. So back to some of the cases and a few extra cases. So I think for the most part, most people got this. So we'll kind of recheck things and see if you've changed any of your answers in terms of this rectal lesion. Okay, so everyone thinks it's a J-Net 2A, which is correct. So again, looking over here, you can see in terms of first looking at the vascular structure, so the dark areas, it's fairly regular in the kind of a repeating mesh-like pattern that you see. And then looking at the surface, so the white part, regular kind of width distribution. And you can't, you don't see variability in the widths or distribution of the white part. So J-Net 2A, this was a tubular villus adenoma. All right, sorry. Let's see. Hopefully it doesn't freeze. All right. And you're right, it was all low-grade dysplasia. So back to this lesion. So the rectal lesion that we saw, again, white light examination, LCI, BLI, and then with a bit of magnification. So for these ones, I kind of wanted you guys to actually tell me kind of a bit more informally. So how would you guys describe this in terms of the gross examination? So Paris classification, LST classification, and kind of J-Net classification. So we still have a number of cases. So maybe for some of the old ones, I'll describe them. And then for the new cases, we'll ask people to kind of chime in. So looking at this lesion, so the periphery here is just slightly elevated. So 2A component, and then this area is a 1S component. And it's predominantly a laterally growing lesion. So this is indeed an LST. So it's an LSTG, so granular mixed type. And in terms of the J-Net classification, kind of when you look closely here, most of it looks like J-Net 2A in terms of the vascular appearance and in terms of the surface appearance. There's perhaps some areas where you start getting a little bit of irregularity or variability in it. So predicting this is probably a lesion with hybrid dysplasia as a superficial carcinoma. So this ended up being just tubular villus adenoma with hybrid dysplasia. And this lesion, which we kind of discussed earlier, I don't think I put a poll in for this one. Yes, I did. Okay. So for this one, if you had to use the J-Net classification, which we just kind of went over, how would you classify J-Net 1, J-Net should be 2A, 2B, and 3. So this poll should have the right markings, but have a look at the images and see here. So how would you classify it? So some people say J-Net 2B, J-Net 3. So this is one of the ones where it's not as straightforward. And you can see, if you didn't use magnification, you'd probably even more difficult. So this lesion, I thought when I examined it with magnification that this is probably J-Net 2B. And if you looked at the old sub classification, it'd be J-Net 2B high for what it's worth. So kind of, oops, sorry. Looking back here. So you can see the surface, you can see the vascular structure, and there is variability in terms of the caliber of the vessels and in terms of the distribution. For the most part, questionable if this area was 3, but for the most part, you see variability in it. So mostly I would say it's J-Net 2B, maybe questionable 3, but I thought J-Net 2B to be high. So this actually ended up being an SM2 carcinoma. So we removed it endoscopically via ESD and ended up being just barely an SM2 carcinoma. However, moderately differentiated, but it did have lymphovascular invasion. He went on to have surgery, didn't have any residual carcinoma or lymph node metastasis. But this is one of those lesions where it was kind of borderline in terms of the examination. So how about this lesion? This was a ascending colon lesion. We can predict low grade, high grade, deeply invasive. So I'll get you guys just to kind of text into Rashad and how would you describe it in terms of just Paris classification? And could you use the LSD classification for this? So any takers Rashad? Some filing in now. I think people are saying 1S, they wouldn't use LST. Yep. So the reason why you wouldn't use LST as well is because LSTs are for lesions greater than 10 millimeters. So that's the other thing in terms of it being predominantly horizontal growth, also bigger than 10 millimeters. Yeah, and a mix of high grade and low grade. So this lesion actually is just a low grade adenoma. So again, in terms of it being, this is with magnification, so it may kind of make it look a bit higher than it is. So it's actually a fairly slightly elevated. So you can see over here, kind of from far away, slightly elevated, it's a 2A, it's a 2A lesion. And this is actually just a low grade adenoma. So again, looking at, this is maybe what you could see here is a questionable valley sign. So again, indicative of, generally consists of low grade adenomas. It's just a very slight kind of soft, kind of going down, not really a true depression. But if you look at everything else, it's again, fairly regular distribution of things. This area you can see is, maybe you can see the vessels a bit more clearly as compared to this background, but they're regular in terms of caliber and their distribution. So this is just a low grade adenoma that we cold snared. So another lesion that maybe is gonna be a bit more difficult. So erectile lesion here. So this one as well, just as we're going through the video, if you can just kind of type in your thoughts in terms of the description, in terms of the pathology or anything that stands out. So the other thing to kind of note, all these two are kind of abbreviated exams, right? So, you know, the prep may not be ideal when you first see a lesion, have to spend a few minutes to wash things and clear them out. And then again, you may change their position as well. Fluid may be pooling on the lesion. So I'll often change multiple positions with the patient. It will not only give you different views of it, but it will give you an idea of maneuverability for resection. So which is gonna be ideal for resection? Left lateral, right lateral, supine, prone, it's variable depending on the location and the patient's anatomy. So I strongly encourage you to kind of to do that as well. We generally don't use propofol or have access to propofol, so it's a lot easier to change patient's position. But I understand, you know, if you're using propofol regularly, it's probably a bit more difficult to change the position. So any descriptions of this lesion thus far, Rashad? Yeah, some people correctly identifying there's, you know, 1S and 2A areas, Paris-wise. And everyone seems to say LST granular mixed type and a mix of, you know, everyone says there's a JNAT 2A area and then there's a mix of some 3 or 2B areas as well. So if you look here, you know, in terms of this, if you just looked at this here, this looks pretty regular, nothing really, you know, exciting. And this also gives you an idea as to why, you know, biopsies are so inaccurate, right? Your biopsies are, you know, a couple of millimeters, maybe four millimeters. If you just take random biopsies of lesion, you know, you're sampling a fraction of the lesion of the surface area. So you can see why, again, they're so poorly predictive of the final pathology in general. So as you said, you know, some people said 2A, some people said 2B, maybe questionable areas of three. So this is just showing you the areas of the lesion. So this was kind of the corner up here. So regular, this area, again, pretty regular 2A and this area here on the side. And then looking at this area here, so you can see it's kind of like, you know, the soft contour here and all of a sudden it's a relatively hard contour, right? It's almost straight or kind of gives you a much more rigid kind of feel, right? And it's a demarcated area, right? It's a demarcated depressed area within the lesion. So often indicative of more higher grade pathology. And then here with magnification. So I agree, this lesion, I was, you know, kind of between 2B high and three. But for the most part, the area was quite small in terms of the area where it was, you know, questionable for three. And again, this is that central area as well. So we removed this with ESD and this just ended up being a tubule villus adenoma with extensive high grade dysplasia. So I was a little bit surprised of the final pathology. I thought it almost certainly would have had at least superficial carcinoma. But again, you can see why, again, J-net, you know, for the 2Bs, crystal violet is, you know, potentially would improve your accuracy. Because again, this had a few high risk features, but during the examination, the things that you'd notice that it moved quite well with suction and insufflation, it was quite soft. And again, the area of questionable, you know, 2B high or three is fairly small. And then this is all kind of very obviously 2B. So it was tubule villus with high grade dysplasia. So in terms of how polyp assessment can help you. So it will help you characterize lesions better to kind of tailor the therapeutic strategy. So in terms of, is this something that you can remove with EMR, remove with ESD, or full thickness or surgery, if you're gonna biopsy it, if you're considering biopsying it, which I think ideally you shouldn't and just take lots of images, with image enhancement, magnification, kind of a different focal lengths are close, far, better than just kind of, you know, randomly biopsying. But if you're going to target it, the most abnormal area and take one or two biopsies. And then in terms of EMR, again, depending on accessibility, I think for the most part, most places have ESD available somehow, whether it's, you know, referral to another center or somewhere in that center. But if there's an area where there's more suspicious parts, so an LSTG mixed type, you know, you remove via piecemeal EMR, the kind of 2A components, so the kind of, you know, flat or relatively homogenous component, and then the dominant nodule, you remove in one piece. Because if there's gonna be carcinoma, it's gonna be in that dominant nodule. And obviously in terms of when to refer to ESD. And it also helps you predict difficulty. So as I showed you in terms of the LST classification, it gives you an idea, the LSTG homogenous mixed type generally are gonna lift up very well, little fibrosis, the non-granulars, even when they're fairly small, can be very challenging to remove because they don't lift very well. The other thing I didn't mention is that the non-granulars have a higher vascular density. That's just something as well to know. Non-granulars have a higher vascular density, so more likely to run into issues with bleeding. So that's everything for the talk today. And if you guys have any questions or comments or anything you'd like me to kind of revisit, let me know. I think there's two outstanding questions, Rob. The first was, when you see a lesion that has chicken skin, and you decide to resect it for other reasons, do you include the chicken skin in the resection? I don't, like I'll include it, but I won't necessarily say like, if it extends like a centimeter beyond it, I won't do that. I'll make sure I take like a margin, usually five to 10 millimeters generally will be the margins around, but if the chicken skin extends, I will extend things further just for the chicken skin. People have, yeah, wondered about that. Is it, again, is it a neoplastic reaction? So it's not necessarily a neoplastic reaction because you saw it's just lipid-laden macrophages. They're not neoplastic. It's just a reaction, whether it has to do with growth factors or what it may be, I don't really know, but you can also see it in obviously not invasive lesions. Sometimes it has to do, again, whether it's with traction or trauma to the lesion, like a reactive, a reactive reason why you're getting this, but yeah, I don't base my resection on the extent of the chicken skin. Okay, great, and then another question, which is very good and probably very relevant question you get from practicing endoscopists is, can you just briefly explain the rationale to avoid or minimize biopsies if you think something may be endoscopically resectable? Okay, so a couple of things. So one, in terms of the accuracy of the biopsies, so a couple of things. So from our experience and also in the literature, the accuracy is probably about 30% in terms of the final histology. Most of the time it's upstaged, okay? So if you just biopsy it and say, oh, it's not cancer, just send it for endoscopic resection. So it may still be cancer, right? It's just they're very inaccurate, the biopsies. So that's one component of it. The other thing too is even if it shows cancer, carcinoma, so as you know, carcinoma can be endoscopically resected if it's superficial. The biopsies are not gonna tell you the depth of the carcinoma, right? So the biopsies will just say, depending on your pathologist, the way that it's reported, they'll say invasive carcinoma or carcinoma. It's not gonna tell you the depth, right? So just because it says carcinoma doesn't mean that this is not endoscopically curable because it does not predict the depth or report on the depth. So that's the other thing. So just the accuracy of them is quite poor. Your endoscopic examination and diagnosis is much more accurate if it's properly done. The other thing is if you take an isolated biopsy, for the most part, it's not gonna make a huge difference in terms of fibrosis. It does cause an inflammatory reaction because it heals as an ulcer and causes fibrosis. It's more of an issue as well in flat lesions. So the non-granular, which are already gonna be difficult to remove because it's so relatively thin, the result of your biopsy is gonna be a lot more fibrosis and scarring that will affect those lesions more so than say the granular mixed, you're taking a focused biopsy of a nodule, for example. So two main reasons, inaccuracy. So biopsies are incredibly inaccurate. So again, if they show you carcinoma, may still be endoscopically curable. If they don't show you carcinoma, it still doesn't mean that there's no carcinoma there. And they cause an inflammatory reaction. As things heal, they heal as an ulcer. It does cause fibrosis. So if you take a carpet biopsies, some people do, it makes subsequent resection a fair bit more difficult. Someone asked if you use chromoendoscopy on top of NBI, and as an aside, could you talk a little bit about your work structure and how that sort of enables high quality exams? Because I know a lot of our colleagues may be in B for service environments. So, okay. So I guess, do I use chromoendoscopy with virtual chromoendoscopy? Is that the question? Okay, so all the examinations I will always, so for talking about colorectal specifically, I will use virtual chromoendoscopy in all cases, for sure. In terms of the indigo carmine, indigo carmine is kind of more of a, you know, again, nice to have. And because indigo carmine is really only accurate for, you know, pit patterns one, so normal mucosa to four to tubular villus adenoma, to be honest, it doesn't add very much in terms of the pathologic prediction in our practice. It's more of kind of a nice to have, maybe gives you a better image, better delineation. But in terms of deciding the final histology, I don't think it adds very much. Crystal violet, on the other hand, is incredibly useful in terms of for your advanced lesions, right? If you're trying to decide like, yeah, I'm pretty sure this is like, you know, a probably high grade superficial carcinoma, maybe more deeply invasive. Crystal violet is very useful. The issues with crystal violet, particularly in the Western population, the prep has to be like pristine. So you have to wash. So there's completely like no mucus, no debris, and even use a mucolytic such as NAC through a washing pipe to clean it all off. And it takes a bit more time. Indigo carmine, you put it on, you'll get your, you know, you can examine it right away. Crystal violet, you probably have to wait a bit or two, then wash things off. So crystal violet is more time consuming, but the lesion selection for it is much narrower. So, you know, you're not necessarily gonna use it on every single lesion. So it's a much narrower indication. And in terms of, I guess, practice, whether you're in a salaried or fee-for-service and volume-based kind of practice, I think, you know, the learning aspect, so when you're learning things, it's gonna be a lot more difficult because things do take longer. So, you know, learning optical diagnosis does take time, and you really have to examine like normal stuff, right? So just examining normal colonic mucosa, right? With NBI, BLI, magnification, you know, and just regular adenomas. So in the beginning, it does take a bit of time, and, you know, your fellow's learning, so things have to take longer. And again, depending on your attending's practice, again, it can be easier in some instances and more difficult in other instances. But the more you practice looking at, you know, regular adenomas, regular colonic mucosa, you know, knowing where the surface is, knowing what the vasculature is, it becomes easier and easier. And then you can still, you know, as you practice it, and you go in your career, you can have a high-volume practice and still do a good examination. So generally, probably one of the higher-volume people in our center, but I still do magnifying endoscopy on every single case. It's, you know, it's knowing that there's not just two speeds, right? It's not just fast and slow. And you have to be able to adjust for the situation. There are cases where you can do things a bit more quickly, and then it's being able to identify the situations where you have to do things a lot slower. So it's not just kind of two speeds, fast and slow. There's a variability in things, and your clinical experience, your endoscopic examination, your knowledge is gonna help you tailor that best to the patient to ensure you do the best exam at the same time the most efficiently. Excellent, thank you. And the last question, can you distinguish submucosal fibrosis versus invasion from narrowband imaging? So narrowband imaging is not really used in the submucosa. So based on, you know, your endoscopic examination, can you say this lesion's gonna be fibrotic or not? Not really, but sometimes too, when like things are extensively biopsied, which causes fibrosis and some neovascularization in the lesion, that can make your interpretation of the JNET pattern a bit more difficult. So kind of hard to sometimes distinguish between neovascularization and an area of maybe a more advanced JNET pattern, so like JNET3 or something. So the extensive biopsies or partially EMR lesions make your interpretation or your optical diagnosis a bit more difficult. In terms of submucosal fibrosis, generally, you know, you can distinguish fibrosis from invasion, because despite the, you know, the fibrosis, usually there's some degree of a plane. Not always, when it's been previously resected, you know, a bunch of times and there's tattoo in it, but usually you can distinguish between, you know, severe fibrosis and invasion. It's, you know, it can be challenging, but generally you can. And magnification as well is really helpful during your resection, if you're doing ESD or even EMR, in terms of examining the submucosal plane sometimes. It gives you a bit more confidence in terms of where to cut, where not to cut, and identifying vessels, again, a bit more easily and confidently. Okay, two more questions. One thing, I'll just plug PRIME. So I've, a couple of people have asked for the PRIME link, so I've posted it in the webinar chat as well as in the Q&A. And then one question which I answered, but I'm interested to hear your take is, if you remove a polyp on block, you know, EMR, ESD, when do you bring them back for surveillance? And I had answered that we usually just follow what the guidelines, you know, if it's, yeah. And if it's piecemeal, then six months, otherwise it's, you know, usually three years or one year if there's more than 10 polyps. Yeah, exactly. Depending on the final histology and obviously depending if it's an R0 resection or an R1 resection, that obviously, you know, if it's an R1, you treat it as it's piecemeal, right, and bring them back. But if it's an R0, then, you know, as I said, just follow the guidelines in terms of the surveillance. Okay, great. And I think the final question is, when do you consider endoscopic ultrasound before doing an ESD? So, almost never. So the endoscopic ultrasound is generally gonna be looking at kind of, you know, lymph nodes generally, right? Or, you know, it's gonna tell you if this is a T2 or T3 lesion, but that generally should be obvious to you on your endoscopic exam, right? It's not gonna be really accurate in telling you like, oh, this is a SM1 lesion versus an SM3 lesion. So it's really gonna be like, oh, this is a T1 versus T2, T3 cancer, which endoscopically should be obvious. So I generally don't use it for my lesion. I know some people like doing it for rectal lesions because of the availability to examine the rectum with it. Doesn't hurt, but it'll probably similar somewhat to MRI in terms of it will overstage, it will say T1, T2, or can't, you know, the MP is like preserved, but maybe it goes down to the MP, you know? So I think optical examination is generally more accurate, but again, it depends on your practice and comfort. And I think the literature supports too. Overall, it's inaccuracy in terms of being able to distinguish SM superficial versus SM deep. Excellent. That's it. I think you've convinced everyone to get their scopes done in Kingston. Okay. Thanks everyone for joining. You know, I hope it was useful and it's always a pleasure for me to give these talks and hopefully meet some of you guys at DDW and some of you I just met at CDW. Yeah, thank you very much. And thanks to the ASGE. I wanna thank you both for your time. I wanna thank you both for an excellent evening. This has been a phenomenal presentation. Thank you both to a GI fellow moderator, our content expert. It's been just awesome. Before we close out, I wanna let our audience know to please check out our upcoming ASGE educational events and to register. You can visit the ASGE website for the complete lineup of our 2024 ASGE events. Our next Endo Hangout session will be Esophageal Strictures and that'll take place on Thursday, April 4th from 7 to 8.30 p.m. Central Time. Again, registration is open. At the conclusion of this webinar, you will receive a short survey and we would appreciate your feedback. Your experience with these learning events is important to ASGE and we wanna make sure we offer interactive sessions that fit your educational needs. As a final reminder, ASGE training membership for fellows is only $25 per year. If you haven't joined yet, please contact our membership team or go to our website to sign up today. In closing, thank you again to our presenters for this excellent webinar. And thank you to our audience for making this session interactive. There were a lot of questions asked tonight and we really appreciate that. Thank you. We hope this information has been useful to you. And with that, I will conclude our presentation. Please have a wonderful night.

optical diagnosis

gastrointestinal endoscopy

Paris classification

image-enhanced modalities

colorectal polyps

systematic examination techniques

NICE classification

JNET classification

magnification techniques

staining techniques

treatment decisions