 is playing it and he'll be talking. There is some issue with his AV. Okay, okay sure ma'am, no problem. Okay, okay. Can you all see my screen, full screen? Yes ma'am. Okay, fine. So we will be talking about Lyrats where to apply and how. So basically I have tried to simplify the concept of Lyrats as much as I can so that once I have finished talking about it, I would suggest that each one of you can probably go back and read the article on Lyrats. It's an ACR document which is easily available. Just go through it so that you understand the concept even better. Okay, so we'll ask ourselves a few questions to begin with. First question is why Lyrats? Okay, now why Lyrats at all? That we need to understand to begin with. So as we all know that when fibrotic changes set in in the hepatic parenchyma, it increases the resistance of the liver parenchyma and this leads to resistance to the blood supply, the portal blood supply to liver. At the same time, there is increase in the arterial blood supply. So basically there is alteration in the vascularity of the hepatic parenchyma which leads to formation of regenerative nodules. Now these regenerative nodules because of the persistent arterial supply, they undergo dysplastic changes and these dysplastic nodules, as we all remember have always been graded as low grade dysplastic, high grade dysplastic, then early at CC and then progressed at CC. So till Lyrats came into picture, this is how the cirrhotic nodules or the regenerative nodules were being classified and this always led to a lot of confusion. So Lyrats basically brought about a common platform for the radiologist, for the treating physicians, treating surgeons, so that each nodule is classified only as a particular category and then the guidelines are laid down for the treatment of that category. So uniform midi and standardization of reporting in chronic liver disease for HCC is brought about by Lyrats and that is why Lyrats has been gotten to reporting. So now on whom are the patients on which we can apply Lyrats, that's important. So we have understood why Lyrats has been documented. Second is on whom do we apply. So we applied Lyrats only on those patients who are at a high risk for HCC. So like the cirrhotic patients, the ones with chronic hepatitis B viral infection or those who are already having HCC or have had an HCC in the past. But more importantly, we need to know that whom do we not apply it on. So we do not apply it on any patient who does not have a chronic liver parenchymal disease, any patient who is less than 18 years of age, those patients who have cirrhosis secondary to congenital issues like congenital hepatic fibrosis or due to vascular issues. So vascular disorders are like butchery syndrome, chronic, portal vein obstruction, occlusion like EHPVO. In these, again, there is a lot of alteration and vascularity of the hepatic parenchyma which confuses the actual regenerative nodules with those nodules which have come because of altered vascularity. And hence, Lyrats is not applied even in these categories. And lastly, Lyrats is also not assigned to the observations which look like typical path-proven malignancies like cholangiocea or path-proven benign lesions like hemangioma. So having understood this, let us understand that what do we get if we apply Lyrat, what are we achieving? As we already discussed, we achieve standardization of reporting. We kind of are able to communicate better with the treating physicians and surgeons because the report is standardized. So my understanding of a cirrhotic nodule would be similar to the physician's understanding of that nodule. There will be no confusion. So that's the major achievement of Lyrats. Again, Lyrats helps in surveillance for HCC which is done by ultrasound. Diagnosing HCC, which we do using either contrast-enhanced ultrasound, which practically, of course, we don't. But in some cases we may where the CT MRI contrast cannot be given. So diagnosis of HCC, predominantly by CT and MRI, staging of HCC, decision on interval follow-up. So once we have staged, we know when to follow this patient up. And lastly, to assess the response to local regional and systemic treatment using CT MRI. So all this is achieved using Lyrats. Now let's see how we do it. But before how we do it, we need to understand what we require. So for cross-sectional imaging, for CT and MRI, two things are very essential. One is multi-phasing imaging with acquisition of a late arterial phase. And second is use of hepatobiliary-specific contrast agent in MRI. These two things are of utmost importance. Late arterial phase. On a 64-slide scanner, we obtain, which we are using, 64-slide scanner with dual energy source. We obtain the late arterial phase at 25 seconds after contrast injection. So for any patient who is a chronic liver disease and who has been sent to us for CT, we definitely do a four-phase CT angio, which Rashmi has already described in her talk. So late arterial phase is of importance. And secondly, use of hepatobiliary contrast is again of importance. So there are two contrast agents identified in MRI. One is gadobinate dimeglubin. And second is gadozactate disodium. Though gadozactate disodium is more effective because 50% of that contrast gets excreted into the hepatobiliary system, it is not available in India. So what is available is gadobinate dimeglubin, in which 5% of the contrast is excreted through the hepatobiliary system. And hence, we obtain a delayed phase, a hepatobiliary phase at around 45 minutes after the scan. And this is of importance when we are categorizing lyrids. So these two are the main requirements, late arterial phase and hepatobiliary contrast agent. Now having said this, this again has been covered in the previous talk, so I would not be going into the detail of it. Again, just for that late arterial phase, I have shown this pictorial depiction and cross-sectional MR, wherein the late arterial phase has been shown. So I will directly go to what is lyrids, like how into the details of lyrids. So basically lyrids uses the term observation to any area with an imaging appearance, which is distinct from rest of the liver parenchyma. So it is something which would look like a nodule or mass like. So such an area may either be a true lesion or may be a pseudo lesion. So first we try to identify any area in the hepatic parenchyma which looks different. Once we've identified that area, we try to classify it into the lyrids category based on the following features, which features major features, ancillary features and LRM features. Now what are these categories? We have LRMC, which means non-categorizable. That means the image cannot be categorized because it's a suboptimal image. Secondly, LR1. LR1 is a definitively benign lesion. LR2 is probably benign. LR3 is where there is an intermediate probability of malignancy. LR4 is probable at CC whereas LR5 is definitely at CC. All the lesions which are probably are definitely malignant but not necessarily at CC are LRM. And lastly we have LRTIV category where the tumor is in the portal vein. So these are the lyrids category. Now what are the major features? Okay, so there are five major features. One is non-rim arterial phase hyper-enhancement, non-peripheral wash out of contrast on the portal venus or on the equilibrium or delayed phases, size of the lesion, enhancing pseudo-capsule and threshold growth. Now let's look at each of this major feature. First is the non-rim arterial. It is very important to understand that it has to be a non-rim arterial enhancement. So here's an example. If you look at this image, there is a lesion here, an observation here which is showing arterial phase enhancement which is all throughout the lesion. The enhancement is not just at the periphery. The same lesion is showing wash out on the portal venus phase and there is some enhancement at its periphery which probably is a pseudo-capsule. So these two are the major features, two major features of an observation. Again, another example of wash out with enhancing pseudo-capsule. So this is one of the major features of lyrids. Now size assessment. How do we assess the size? It's very important to remember that size has to be assessed on a non-arterial phase. Why? Because on the arterial phase you get a perfusion, alteration around the lesion also. So there may be some hyper enhancement around the lesion and that may lead to wrong assessment of the size of the lesion. So you always measure it on a proto-venus or on a hepatic venus or a delayed phase. Always measure the lesion from outer edge to outer edge, never from inner to inner. Never exclude the capsule. Always include the capsule. Use the longest dimension of the lesion. Take the entire observation. Sometimes you may see patchy enhancement in a lesion. You try to include the entire observation. If there is a nodule within nodule, you always measure the outer nodule. So size assessment, very essential to understand how to assess the size and on which phase to assess the size. Having said this, we go to the next major feature that is threshold growth. How do we classify threshold growth? Increase in the size of the observation by more than or equal to 50%. In less than or equal to 6 months. Now this has to be applied only if the observation is unequivocally amass. Secondly, we try and apply it only if the CTNMR are of appropriate quality and technique. And thirdly, we try to compare these lesions on the same phase or sequence or in the same plane as far as possible. So this was all about the major features. Now let's see how do we go about applying lyrax. So there are three steps. Step one is where we apply the major feature. Step two is where we apply the ancillary features and step three is where we apply the tie breaking rules. So let's go to step one. So based on step one, untreated observation where there is no pathological proof in the patient who are at high risk for HCC. The lesions or the observations and categorized as such, which I've already described to you. What is important to know is that the above categories can easily be diagnosed without using the diagnostic table. So once the lesion is non categorizable, you're going to call it LRNC. Tumor in vein, I will be coming to that image is again very specific and can be categorized. LR1, LR2 lesions, which favor benignity are again easy to diagnose. LRM is any lesion which is not HCC specific but looks malignant, even that can be diagnosed. The question comes as to how to diagnose these ones, which are those borderline lesions. So LR3, LR4 and LR5. These are the ones wherein we require the diagnostic CT MRI table. So just example of the LR1 lesion. So all those which are definitively benign like cyst, hemangioma, any perfusion alteration, any small arterial portal shunt, any hypertrophic pseudo mass or a scar. All this would be labeled as LR1. Now LR2, LR2 are basically the regenerative nodules. So any solid nodule, which is less than 20 mm in size, it looks little distinct from the background nodules but has no major feature of HCC. So no major feature means no arterial phase hyper enhancement, no washout, no capsule, no growth. All this would be labeled as, all these nodules would be labeled as LR2 nodules. Even the nodules which are T1 hyper intense, T2 hyper intense, sidirotic or hyper intense on the HBB phase are labeled as LR2 nodules. Now, yeah, so this is an example of LR2 nodule. We have this background heterogeneous liver and if you can appreciate these hyper intense nodules on the T2 weighted sequence and the same on the post contrast scan. So these are typical examples of regenerative or LR2 nodules. Now coming to the diagnostic table. This is the most important table of LIRAC and it's very important that we have it in front of us on our desk because it's not possible to actually memorize and use it. It's very easy. We place it in front of you on the desk and refer to it whenever you are reporting a CLD case. So in this table, if you see these are the major features that have been lined up and it has been divided into two categories. Non arterial phase hyperenhancing lesions and the non-drill arterial phase hyperenhancing lesions. So the lesions which are non arterial enhancing are then categorized based on their size into less than 20 and more than an equal to 20 mm. And the lesions which are arterial phase enhancing are classified into three categories less than 10 mm between 10 to 19 mm and more than 20 mm. So you look at the observation you see whether it's arterial enhancing non arterial enhancing then you look at the size of that particular observation and then look at the other major feature. And then if there are no additional major features they are categorized in this category. If there is one it fits in the second row and if there are more than two or equal to two major features they fit in the last row. That is how we go about. So if I have to kind of decode that table then this is how I have. I will read this out to you but you need not remember it. Basically LR3 lesions are the lesions which measure less than 20 mm but are arterial enhancing and there are no additional major features. For the non arterial enhancing lesions which are more than or equal to 20 mm with no additional major feature they also fall in LR3 category. The lesions which are again non arterial enhancing and less than 20 mm but having one major feature would also fall in LR3 category. Similarly for LR4 category we have those lesions which are less than 10 mm but are arterial enhancing and demonstrated at least one of the three features would fall in this category. Lesions which are not arterial enhancing can also be categorized as LR4 only if they are more than 20 mm with one major feature or less than 20 mm with two of three major features. Similarly LR5 any lesion which is more than 10 mm and arterial enhancing favours LR5 lesion. Those measuring more than 20 mm and demonstrating at least one of the following three features or those between 10 and 20 having at least two of the three major features also fall into LR5 category. Again as I said there is no need to memorize these. Look at the table you will be able to classify the Lyrides category. Now we go to step two. So step one was where we applied the major features. Step two is where we apply the ancillary features. Now how do we apply the ancillary features? So any ancillary feature which favours malignancy would upgrade the category by one up to LR4. So if it's a LR3 lesion but there is a feature which is favouring malignancy additional feature I would upgrade that lesion to LR4. But if I'm seeing an additional feature in LR4 there is no way I can upgrade it to LR5. It's not allowed. Similarly any ancillary feature which favours benignity would downgrade the category. So LR3 lesion with one ancillary feature which is favouring benignity the category gets downgraded to LR2. Even LR5 for that matter can be downgraded to LR4. You always remember LR4 cannot be upgraded to LR5. Now what are these ancillary features? So let us right now focus on this and this. You need not save this slide. This is again available in the Lyrides document. So the factors which ancillary features which favour HCC are non-enhancing capsule, nodule in nodule appearance, mosaic architecture and presence of fat and hemorrhage in the mass. Ancillary features which favour benignity are stability of size of the nodule, reduction in the size of the nodule. When the nodule parallels the blood pool, the vessels are not distorted. There is presence of iron in the lesion which is more than that in the parankaima. There is marked T2 hyperintensity of the lesion and there is hepatobiliary phase isointensity. So these ancillary features are laid down. We just need to know them and we have to then apply them to further upgrade or downgrade the category. Then we have this, so these are the examples of ancillary features. So we have a T2 weighted sequence, T2 weighted image wherein we see this hyper intense nodule. And on the arterial phase there is some faint enhancement in that nodule with washout and a pseudo capsule on the delayed phase. So this is typical example of nodule within nodule. In this case, how will we measure the size? We will not just measure this nodule, we will measure the entire observation and we will measure it on this phase. So this is an example of ancillary feature. Now another example of ancillary feature wherein this is a dual eco sequence. We have a lesion which is hyper intense on in phase and on the opposite phase it is showing loss of signal which indicates presence of fat within the lesion. This is another ancillary feature and this is a typical example of mosaic architecture wherein it is a lesion which is not really very well defined. The periphery of the lesion is not well defined. There are multiple areas of contrast enhancement and areas of contrast washout with a typical multi-nodular appearance. Now it's the type, the step three that we will first talk about. So step three is where we are not sure. So when we are not sure we have to apply the type breaking rules. So what are type breaking rules? For an LRTIV category, if we are not sure that whether the tumor is a tumor thrombus, we may be confused between bland and tumor thrombus. It is okay to label it as no TIV rather than calling it LRTIV. Again when we are unsure about two categories we can choose the one which reflects the lower certainty. So for example, if there is a lesion which is LR2. But there is a lower certainty of benignity. There is something about it which tells us that this could be LR3 but we are not sure because they are not typically fitting into that category. Then we can categorize it as LR3. It's okay to overgrade it. When there is a low certainty of malignancy it is okay to undergrade it. So LR4 lesion, you are not very sure and you still feel that the benefit of doubt should be given. You can label it as LR3 but at the same time ask for a follow-up within three months for that lesion. When there is some uncertainty about the diagnosis always ask for an interval follow-up within three months. So having said this let's try and look at a few examples because that will help us understand this whole concept much better. And what I would suggest is before I show you what it is you can probably even go on to your chat box and enter what LR category you feel it is. Okay this will just help you correct yourself. So here's an example wherein you these are the phases so arterial phase, portal phase, delayed phase. We are seeing a nodule the size has been measured for us it is 18 mm size. There is no arterial phase enhancement at all in that lesion. It appears hypotenuated even on the potovenous and on the delayed phase. There is plus minus maybe an enhancing capsule around it. On the delayed phase. So it's an 18 mm size lesion which is non arterial enhancing. So I would be looking at the non arterial enhancement column less than 20 mm size and then looking at the additional major features. So if I'm calling that an enhancing capsule it would still categorize as LR3. So this is an LR3 lesion. Okay now I'll go on to the next case. So here there is this nodule which is 13 mm in size which is arterial phase enhancing but not showing any wash out on the potovenous phase. It shows equivocal or hypo enhancement or wash out on the delayed phase so we are not very sure of it. So we have a nodule which is 13 mm in size and arterial phase enhancing. So I will look at the non-rematerial phase enhancement column and I would look at the category here. So it kind of fits in this column. Then we look at the major features. So is there any capsule? No. Is there any wash out? No. Threshold growth we are not aware of. This is not a follow-up scan. So essentially this falls in which category? LR3. Okay. Then we go to the next case. So in this case we are seeing two arterial enhancing observations. I've measured the sizes here. One is 10 mm in size. The other one is 22 mm in size. If you notice here if I would have measured the size on the arterial phase what would have happened? I would have measured the size wrongly because they look much bigger on the arterial phase. So we have one observation which is 10 mm in size and arterial phase hyperenhancing and showing a wash out on the venous phase. So if I look at my table it falls in the arterial phase enhancing category which is 10 to 19. So this column and it is showing a wash out. Now take a look at this particular cell wherein you see LR4, LR5. So what does that mean? So the observation will be called LR4 if there is an enhancing capsule around it. It will be called LR5 if there is non peripheral wash out or threshold growth. So in this case there is a non peripheral wash out. So I would want to label my this lesion as LR5. Now a 22 mm size lesion which will fall in this category more than 20 mm which is showing a wash out also showing a pseudo capsule. So two features. So it will fall into which category LR5. Another case this is about an 18 mm sized nodule which we are not seeing at all on the arterial phase. We are seeing it faintly on porto venous phase but we are not sure of it. But look at the venous phase definitely there is a hypo enhancing nodule seen on the venous phase. So if I have to label it just on these features that is 18 mm the major features. So it is an 18 mm sized non arterial enhancing. So it is in this column. And it has some wash out which is very faint but yes we call it a major feature. So I would want to call it LR3 nodule. But then I look at the in and the opposite phase and what do I see? I see presence of fat in it. So it becomes one of the ancillary features which favors its easy. So I have to upgrade my LR3 nodule to LR4. So this becomes essentially LR4 nodule. Now next case a lesion which is mildly hyper intense on T2. It is iso intense on non contrast T1. It is arterial phase hyper enhancing and it is showing wash out with a pseudo capsule on the porto venous phase. And it measures 38 mm in size. So again we are looking at this column a lesion which is more than 20 mm. With arterial phase enhancement with wash out and with pseudo capsule. So we are looking at an LR5 lesion. All right. Now here's an example of tumor in vein. On this T2 weighted sequence we are seeing a filling defect in the posterior portal division of right portal vein. It is expansilitis caused dilatation of the vein. It is iso on T1 enhancing on the arterial phase. And on the porto venous phase we see an arterial enhancing lesion with a wash out and a pseudo capsule which probably is an LR5 lesion with this arterial enhancing thrombus in the portal vein. So this is definite example of LRTIV going on to LRM. So any observation which is mass like but is not following the HCC kind of enhancement. So if you look at this lesion it is a mass like lesion which is non encapsulated not showing significant arterial enhancement and is heterogeneous on the porto venous and dilate sequences. So this has to be labeled as LRM. It looks like malignancy but definitely not HCC. So it will be labeled as LRM. Now let's go to the treatment response categories of LIRADS. So we've finished with what means I've tried to simplify LIRADS as much as I can as to have to try to apply it. Now also let's take a very quick look at how to apply it in the post treatment cases. So in post treatment cases LR is called as LRTR, LIRADS treatment response category which is non-evaluable if we are not able to evaluate the response. It is non viable when there is absence of tumor tissue in the treated lesion. It is equivocal when there is no surety. It could be viable. So then we label it as equivocal. And LRTR viable is where the lesion is treated but then there's still presence of viable tumor within it. But how do we, what do we call viable? Any lesion with a peripheral rim enhancement should not be labeled as viable. The peripheral rim enhancement if a local regional treatment has been done could represent an inflammatory rim. But if the enhancement is nodular, mass-like or irregular and is showing arterial phase hyper enhancement or washout or enhancement similar to pretreatment, it should be labeled as LRTR viable. So these are the examples of the nodular enhancement, a nodular enhancement with lobulated margin. So it looks plaque-like or it is just an irregular plaque-like enhancement. So these are the examples of how the viable tumor tissue would look if we have to label it as LRTR viable. So here's an example. This is the same LRFI lesion which I just showed you five minutes ago. So this lesion was then treated with Tase and this is the post-treatment MR. So on post-treatment MR, what do we see? On the arterial phase, there is no enhancement, though there is some faint peripheral enhancement that we are seeing. On the protovenous and on the venous phases, there is absolutely no enhancement seen or nothing seen around the lesion. Effectively, the lesion seems smaller in size. So this is an example. This peripheral hyperintense or enhancing RIM is actually just an inflammatory RIM and it's an example of LRTR non-viable. Now here's an example of a scan with follow-up. So we mean this was initially a treated lesion. This was the first follow-up in which we saw a viable tumor tissue. And this is how we measure it, the viable tumor tissue in its longest dimension. So it was 30.5 mm. It was not only showing arterial phase enhancement, it was also showing washout. So this lesion was then treated with RFA and what you see on the third follow-up that is in August, a month later, two months later. There is definitely decrease in the size of the viable tumor tissue. We do still see a small area of arterial phase enhancement in the periphery and it is also showing some washout. Even though this washout would not be there, still this kind of nodular enhancement would favor a viable tumor tissue. So this is definitely LRTR viable, example of LRTR viable. So having said this, I'm concluding my talk by basically summing it up. So what is important in LIRATS appropriate scanning technique, understanding in whom we apply LIRATS, understanding whether the observation is a mass or a pseudo mass and then classifying it into LIRATS category. LIRATS category have been made based on the major features, ancillary features and LRM features. So for LR3, LR4 and LR5 always make it a point to look at the chart and then try to classify them and that is how we assign LIRATS. Try if possible to go and read this article, this entire document by ACR. That's about it. Thank you so much. Any questions? I'll take them in the chat box and I'll reply them in the chat box itself. Thank you so much ma'am.