Yeah, so you bring up a really important barrier to adoption is confusion about how to do it. And part of the reason why we decided to get together and try to build MLDMAX is so that people teaching it are using consistent language and consistently teaching it the same way, and it was kind of vetted as a reasonably agreed-upon way to do it based on the data. That hasn't happened as much for IBIS as it has for OCT. I'll give you my approach to it. Typically if it's heavily diseased, I'll go mid-plaque to mid-plaque. As the stripe between the EEL and the lumen increases, you've got more potential risk for edge dissection, because there's a thick rind of atheroma there. So in those cases, it's completely fine to say, I'm going to make a luminal measurement, and I'm not going to worry about where the EEL is, because maybe I'm not good at reading it. Maybe it's a bad image like Kate showed. I can't get it. And there is no hazard to that. If you make a luminal measurement, you're probably going to be too small on your distal stent choice. And when you post-dilate it and then do your second imaging run, you'll figure that out and you can adjust and then dilate higher. So as the artery becomes more diseased, it's harder to size it based on how you measure. My way is mid-plaque to mid-plaque in that case. Some people might say they're medial guys or gals. They probably have a little more tendency to have edge dissections, but they have less post-dilation to do. So if you kind of understand the process and what your endgame is, you can make decisions about which place you're going to measure, understanding, ah, I may get a little small, but I'm going to fix it at the end, which is the important part. But I would just sort of simply, if you want to take my approach from my experience, I think mid-plaque to mid-plaque in disease segments, and then you obviously go back and forth and look for the least diseased segment to stand in. So the MLD is morphology, length, diameter. The M is morphology, not just to the calcium you need to make sure you modify, like Kate showed. It's also that morphology of where you land, with the idea that landing in TICFA is probably the most dissection-prone place. So look for that, too. Kevin, Kate, what about calcium rules for OCT and IVUS? When should we do something more? Because everybody gets confused about 180 degrees, 270 degrees, thickness. What are the rules? Take that, Kate. Yeah, sure. I think from a practical standpoint, you know, we're not making a score all the time. And unfortunately, you know, it's perfect if that's a 5-millimeter lesion. Maybe you can do that. But a lot of times it's fairly heterogeneous, which is kind of the issue in this case, too. So I think on the run, we just basically start with the arc. If you're circumferential, I'm worried, like, we need to do something. And then deciding what that something is depends on how heterogeneous it is beyond that and if it's more than 5 millimeters. So really focal stuff, I'm more willing to do balloon-based strategies. If it's diffuse, then you're seeing that, you know, regardless of the thickness and other things. I think atherectomy is going to help facilitate the case, so we'll just move to that quickly and then go back and recheck everything after. So I think from a practical standpoint, an arc more than 270, I'm just already thinking something is going to need to be done. And if it's focal, maybe balloon-based, and if it's more diffuse, then I'm just moving to atherectomy quickly. Yeah. Kate's discussion is incredibly practical. There is more granularity if you're inclined. There's two scoring systems, one for IBIS, one for OCT, and they're correlated with something we care about, stent expansion. So if you see a calcium volume index of 3 or 4 by OCT measured by thickness, length, arc, and it's high, you know that if you don't do something about prepping the vessel, your stent's not going to expand well, the patient's at risk. Same thing for IBIS. The IBIS score encompasses arc, length, nodule, and smaller arteries are a little harder to expand, less than 3.5. And so it's neat because it's someone that teaches complex PCI and goes to our same calf conferences you all go to. I was always frustrated by the fact that Sahil's atherectomy choice might be different than mine, and he's a damn good operator. So we had like no consistency of when it was time to pull IVL, Rota, or Orbital. Now there's at least a guidance. If you want to get into the weeds, you can say, look, this score is a 2. I can maybe try a Wolverine or an angiosculpt, but it's a 4. I'm going to need to do something more deliberate. So there's really clear guidance that correlates with outcomes of something we care about. That's all we really care about is expansion and the edge dissections for optimization. Jim Thompson. Okay, so the optimal stent, you always talk about we should land the proximal and distal stent where there's less than 50% flat, right? How do you make that determination? Do you do it just visually on IVLs, or do you actually use the software to measure the plaque to determine if you're landing the one that has less than 50% flat? Yeah, so I tend to be painfully practical. If there's three randomized trials and we can't get anybody to use it, the minute in a session like this we start teaching plaque burden, people are going to be like, oh, this gross guy from Harvard thought it was mine, I'm not doing that, and we lose the game. From a simplicity standpoint, normal to normal, impossible. If that's not possible, most normal. And if you really want to get cool about it, you can start to look at plaque burden. You can think about how much disease is there. But at some point, you're going to be extending proximal and distal, which with DES, there's not a lot of hazard to you, and it's probably better to cover normal to normal, but you always have to measure in terms of how much stent length you're adding. Measure it, I mean, try not to do too much, and then if you start crossing major side branches and you're pinching them, there's a hazard to it. So I think that we can talk about an IVUS signature of where to land based on plaque burden, which is what they used in that ultimate study I highlighted, but we're not there yet. We got to teach people just the value proposition, how to use it practically, practical approach to calcium like Kate did, but there's really neat ways if you want to be an IVUS expert where you can say, alright, I know if I land in less than 50% plaque burden, I'm doing the patient service. I hope we're having those discussions two years from now, that'd be great. Great question, and real quick, for every operator in the room, who's using an algorithmic approach to their intravascular imaging? So not just putting the camera down, but doing an algorithmic approach. Emily Max or some strategy from there. IVUS 1-2-3 is another one being used. IVUS 1-2-3, yeah. So if you're not, you know, talk to the panels afterwards, look a little bit into the literature, but I think that the only way to get good about imaging is to be systematic about it. The only way to be able to teach imaging is to be systematic about it. The only way to get really consistent outcomes is to be systematic about it. So I'd encourage everyone to incorporate an algorithmic approach for imaging, whether it's Emily Max, 1-2-3, some other system that you've been taught or developed, but I think that's critically important, and I think that's how a lot of the high-volume operators tend to approach intravascular imaging.

intravascular imaging

consistency in teaching

consistent language

measuring arteries

calcium in imaging