Well, let's talk about the clinical utility of type 1 versus type 2. So first of all, with regard to large lesions, we are in the midst of what is often called the cold revolution. I like that term. We're moving more and more toward cold resection. And this is, I think, clearly established for the SSLs, less so for the adenomas. But there's a group of adenomas, particularly flat Paris IIa lesions, where it's quite reasonable to perform cold resection. Bulky ones and ones that have pseudodepression adenomas really can't do. But if there's very low risk of cancer, cold resection may be appropriate. But it's appropriate for basically all the SSLs, and we can use NBI to distinguish those. Then the diminutive lesions, leaving distal colon type 1 lesions in place. These are basically mostly hyperplastic polyps. And then resect and discard. Now, resect and discard I won't say a huge amount about tonight, because although it's been endorsed by the ASGE, the tech committee of the ASGE said it's basically ready for prime time. The ESGE has said the same thing. In the United States, we don't do it very much. It's not because the science is not there to do resect and discard. It's because the politics are not there. And the big problems, I think, are that a lot of people perceive it would have medical legal risk, and there's virtually no financial incentive for it. In Japan now, there is a code, basically a payment, for the use of enhanced imaging, including NBI. But we don't have anything like that, and we're unlikely to get it. So let's talk a little bit about these uses and see if we can learn how to do this. Okay, so here we're focused on type 1 versus type 2. The type 1 features lighter color, either no or lacy vessels, and then usually dark spots that are surrounded by white. You can have white spots. This may depend on the angle that the light enters the crypt. And then type 2 lesions tend to be browner. The vessels are thicker. And in the highest confidence lesions, I think, structures that are oval, tubular, or just variable in shape. Ideally, the pits are much more variable than they are in type 1 lesions, and these are the adenomas. So as I mentioned, for narrowband imaging, as well as for some other optical imaging techniques, the evidence overall suggests that the data is quite good. We have in the ASG the PIVI criteria, which say that if the technology can be used and you can reach the correct surveillance interval, you know, more than 90% of the time, then it would be reasonable to do resect and discard. Again, we don't do that. Same thing for distal hyperplastic polyps, if the technology can be used with negative predictive value for adenomas more than 90%, then you can do it. So the data is there that it works.

clinical utility

gastrointestinal endoscopy

cold resection

narrowband imaging

lesion identification