Chapters Transcript Video Cardiac PET in 2026: From Quantification to Clinical Transformation Dr. Al-Mallah discusses the diagnostic accuracy and acquisition protocols for cardiac PET non-invasive test for detection of CAD. Good morning, everyone, and thanks for having me. OK. So today I'm tasked to talk to you about cardiac path and, uh, these are my disclosures, if I can move slides. OK. All right. So, let's dig into cardiac path in general and then we'll see where it fits in the overall scheme of patient management. Obviously, we're not here to say that this is the only modality that we will have. There is a major role for CT, MR, and echo, obviously, for everybody, and I think it is, for a health system like yours, it's a very important modality to have in addition to the other modalities. So, what, what do we do with cardiac PET? I mean, everybody thinks of PET as myocardial perfusion imaging. It's like the, uh, rose rise of, uh, SPECT imaging or nuclear imaging where we look at myocardial perfusion imaging, but there is way more to that, and I'll focus more on myocardial perfusion imaging, but I'm going to touch more, a little bit on, We do viability imaging, inflammation imaging and sarcoid. We also do infective endocarditis imaging, and we look for inflammation and, uh, infection. So, and even now amyloid imaging. So, there is a lot on the menu. I would say in my practice now, about 70% are these perfusion imaging and 30% the other ones. And the other ones are extremely important, And this is where it will make a difference to have it in a center like yours where you have a lot of advanced procedures, a lot of, uh, critically ill patients and otherwise. So, let's start with the perfusion imaging. Why cardiac path? Like, why do we need cardiac path for this? Well, for, the cardiac path has these characteristics. If I just remind you of this, I mean, we have very high diagnostic accuracy. And I'll focus a little bit in details, a little bit more, uh, high quality images, low radiation exposure, short acquisition protocols, and then, uh, quantification of blood flow and strong prognostic power. So let's dig deeper into this. So why in terms of accuracy? So, there have been several studies that looked at it in different populations, but I'm going to show you one study, which is probably very hard to replicate. It is a study done in the Netherlands where they brought a patient, the same patient had a SPECT, PET, CT, FFR CT, and then they took them to the cath lab and did three vessel FFR. Uh, don't ask me how they got IRB approval, but it was done. And it gives us a great opportunity for 200 patients to look at accuracy overall. And the most accurate overall was PEET among all these tests that were done on the same patient, same time compared to invasive FFR. So, if you look at SEC, the sensitivity in this study was 57. But it was very specific, 94, with an overall accuracy of 7.7. PET has the highest and very balanced one. CT is extremely sensitive, as the CT leaders in the audience know, but the limitation has always been the false positives and the accuracy is 74. Even when adding FFR CT, PET was still the most accurate among the, all the testing there. Now, in terms of image quality, I know that we are struggling with different patient populations, different body habitus for the patients. I'll show you the patient that I did in my center with a BMI of 76. Don't ask me how we managed to fit them in the camera. Um-hum. But, yeah, BMI of 76 was still the lower than the table limit, and you can see here the image quality. I don't think we are able to do it with any other imaging modality, and with this one, it's less than 2 millisiever. So, despite that, it's less than two millisiever for this patient, and this is the kind of image quality you should expect with cardiac path when you do it. And this is kind of the zoomed image where we put that. I think with pet because most pet machines now are PET CT. We have a golden opportunity to look at not only stenosis, but also look at atherosclerosis. And for many years, we focused, whether on CT or nuclear or cath, we focus so much on stenosis, or you don't have a 70% stenosis, you're fine. Nope, they're not fine if they have atherosclerosis. And for nuclear, we only detect the obstructive disease, but when you combine it with the calcium score or even the CT attenuation correction, where you look at calcium, now you know that the patient will have atherosclerosis. What will determine the long term outcome based on studies from our group and many others, is not whether they have a 70% stenosis. What will determine if they're fine 10 years down the road, Is what, how much atherosclerosis they have and how can we manage that atherosclerosis. And the guidelines have accepted, approached that and clearly said that. I mean, in my practice, we say every patient without known CAD, this has been our approach since 2010. Any patient without known CAD, so if the patient doesn't have a stent or bypass, they're going to having a calcium score. And we're backed up by a class 2A indication from the ACC guidelines in 2021. So anyone, it says, for intermediate high risk patient with stable chest pain, no known CAD, Addition of calcium score can be useful. Believe it or not, the European Society of Cardiology gave it a class one indication. So, technically, looking for atherosclerosis is extremely important. And I think it's about time to move on from this kind of paradigm where we looked at all imaging modalities. All our patients with coronary disease, we've been thinking, oh, do they have an obstructive lesion or not? Do they have ischemia or not? Whether you look at it on CT, whether you look at it on functional imaging, or even in the cath lab, oh, the patient doesn't have a 70%. I think we need to move on differently and now look at it this way, whether the patient have, Atherosclerosis and ischemia, or no atherosclerosis or ischemia, or atherosclerosis, but no ischemia, and this is kind of the bulk of the group, or the last group where they have atherosclerosis and ischemia, the management of these patients is very different, and obviously revascularization is going to help the symptoms in this group, but this group we've kind of quote unquote, abandoned for some time. And now it's about time to push them to be well treated and managed for this. And as I said, we're doing all of this with PET with extremely low radiation exposure. This is kind of like different nuclear techniques, but you can see that with rubidium PET, we can do actually between 1 to 2 millisiever. In fact, we use a BMI based dosing, so technically we are doing, Like 2020 to 30% of our patients on PT are less than 1 millisiever and the rest are between 1 to 2 millisiever. We rarely cross the 2 to 2.5 millisiever, no matter how obese these patients are. And then we can prognosticate patients. Now we have data on the outcomes of these patients on at least 60,000 patients that have been published, let alone the thousands of patients that has been happening. And then probably if I want to keep one idea for you, what is PET doing that nobody else is doing, except my cardiac blood flow. This is probably the value proposition for cardiac path because we are able to quantify blood flow. So, our colleagues in the cath lab, when you, CFR and blood flow in the arteries, not the FFR, which is the lesion specific, but even digging down to the microvasculature, I think it's going to be helpful. The good news is that this is not something that you need an additional acquisition. It's pure processing of the initial data. And believe it or not, Medicare recognizes its value and reimburses you additional money just for doing that reconstruction and looking at it and reporting it. So, even though PET is well reimbursed, this one is an add on code that brings additional money to the service. So, it's pure quantification, sorry, pure, uh, reconstruction that you do on the machine, and then it takes less than one minute on the, Um, on the software to give you the numbers that we teach, like on different courses, how to use them, how to measure them, and how to interpret them. So, and one of the advantages of blood flow is, for example, it's negative predictive value. So, if you have somebody with normal blood flow, it's extremely unlikely that they have obstructive disease, or at least high risk of obstructive disease. So, it kind of moves our shift from looking at the epicardial vessels, to look at the entirety of the heart, uh, perfusion, And looking at both epicardial and microvasculature, because sometimes they go hand in hand, sometimes they don't. And here's one case that I'll show you. This is a 79 year old patient with chest pain, and this can be obviously multiple things, but perfusion looks normal, so stress on top, rest on the bottom, and looks no perfusion defect. But when we did the calcium score, you can see all the patient vessels have a lot of calcium. So, this is obviously somebody with atherosclerosis, but I want to know now, is there obstructive lesion or not? Irrespective, this patient is a high risk based on atherosclerosis and need to be treated, need to be well controlled in the clinic, need to see his primary care, sorry, his primary cardiologist to ensure that their LDL, Should be treated with secondary prevention guidelines and others. But now, the question that remains, do we have obstructive disease? If you know from our CT colleagues, when I'm reading CT, I don't want to see this patient in the CT lab because it would be a nightmare to try to be able to interrogate every segment and figure out if there is obstructive lesion or not. So, when we measured the blood flow of this patient, you can see at the blood flow was 0.66. When we gave them rigadenesone, it almost doubled with a flow reserve of 2.2. So that kind of makes me very comfortable that this patient does not have obstructive disease, And they're able, despite all this atherosclerosis, they're able to generate enough blood flow to their myocardium, and technically this patient doesn't need to go to the cath lab. This is all at this moment when we did the testing. Now, if we leave them without therapy, Then they will progress to obstructive disease, and then we will be in trouble for that. And we can look at it even segment by segment, and it tells you that depends on how well the atherosclerosis is worse, the blood flow per segment is a little bit different, which tells you also that you need, To focus on this because there are some segments that are borderline and this will indicate like mild to moderate lesions that does not need to be revascularized at this time, but hopefully we can stabilize these plaques in there to prevent progression. And we know from outcomes data that these patients who have low flow, even if they have no obstructive disease or no specific perfusion defect, they will do worse, uh, uh, with low flow. And this is a, an important study that we recently did, actually just came out a few months ago, looking at 8000 patients in our practice, and we followed them up. They had PET and we looked at the flow reserve. And here you have the ejection fraction and you have the flow reserve, irrespective of where the flow, their ejection fraction. If they have low flow reserve, these patients are going to be in the high event rate, which is specifically looking at death or heart failure revascularization. In fact, if anything, I can tell you that a resting blood flow is your best indicator if the patient is going to come back for a heart failure admission. This has been, like, we were spearheading this, and now we are seeing it more and more. So, those patients, like, I'm pretty sure you have, like ours, like other places struggling with heart failure readmissions. You want to keep these patients out. You want to know. If they, if you know that somebody had a PET scan and the resting flow is high, be certain, That this patient is at high risk of coming back to the hospital with a heart failure admission within 30 days. So, this is one of the markers, you can see here that among those with a blood, resting blood flow above 1.2, they're almost more than 4% that they will be coming to you with a heart failure admission in the coming, so we're not only just, Looking for obstructive disease now, but now we're looking at the overall myocardial health and trying to personalize our care for these patients, looking at atherosclerosis, looking at overall perfusion and trying to explain whether these symptoms are from obstructive disease, but also looking at Huff puff and prediction of further half path. I want to show you another interesting case where, The cardiac path could make a huge difference in the management of these patients. This is a 56 year old lady coming in with exertional dyspnea and chest pain, BMI of 51. She is so symptomatic that she's unable to move around. She had, as you may expect, in the past year or so, Sorry, in the past few years, multiple hospital admissions, ER admissions. She comes in one time with shortness of breath, one time with chest pain. I see some people smiling because this is not uncommon. We do see this, uh, Ms Jones in the ER again with chest pain. And you go in, one time she will have a SAT, one time she will have a PET, and one time she ended up with some symptoms, so she ended up with a cath and demonstrated no obstructive epicardial disease. One time somebody suggested, oh, this might be, uh, myocarditis. We did an MRI. The MRI was fine, no LGE, nothing in there. And then we started our PET program. It's like, OK, let's take her to the PET lab and try to understand what's going on. So, as we discussed before, her profusion is normal. We know that her cath is normal, so I'll be very surprised if I find a focal lesion. But when we did the calcium score, it's about 581, so she is somebody with atherosclerosis, but that doesn't explain this recurrent chest pain or dyspnea in there. Now we did the blood flow, and this is how it looks on the software, so let's zoom on on the numbers. Her resting flow is like upper normal, I would say. It's not too high. But when we gave her agadenesone, her blood flow did not increase, and her flow reserve was 1.35. So this is a patient who doesn't have the ability to vasodilate. So every time she's trying to get out of her bed, to move to the kitchen or to do her daily activities, she's getting short of breath because she doesn't have reserve. This patient is so short of breath because she does not have reserve. So how do we fix that? And this is what the guidelines refer to as coronary microvascular dysfunction. So, the biggest question is, like, what are we going to do with this patient? How are we going to handle her? So we had to sit down, me and her cardiologist, and with her, and we said. We know what's going on. That's why you're coming back, because your arteries are not, and the primary suspect in your case is your BMI, your, like, mainly because it's obesity, and we know that obesity, we and others have published also that obesity can limit your ability to vasodilate. So, why don't you just think about, this is before the Ozempic days, but actually during the, like, the early days that the results were out, but not widely available, But we said, like, maybe it's a good idea that you go ahead and have bariatric surgery. So, after long discussions, like, I'm not going to live like this my rest of my life, so she ended up with bariatric surgery, and then the first year or so, she had 75 pound weight loss. So I said, OK, let's bring her back and see what happened to her microvasculature. So, now you see her, uh, PET with a BMI of 39. Far from being ideal and normal, but coming down from 52 to 39. Her calcium score is relatively stable. I mean, mildly increase probably from statin therapy. And let's go and look at her numbers. I'll put both numbers next to each other. This is a BMI 51, BMI 39. Look at her resting flow, almost identical over time, no change. But what happened here? Look at her ability to vasodilate before, and now when she lost weight, 2.41. And look at her flow reserve, 1.35 to 2.62. And more importantly for me is that she was feeling fine. She was feeling much better, no ER admissions, and the patient was, like, the first time she came in on a wheelchair, now she's coming in with walking and she's like, I feel very, very different. So, What we know that not all chest pain is from obstructive epicardial disease, and what we also know that our guidelines have advocated that, saying that for those type of patients, which is not a small number, by the way, Just look at your cath labs, look at your clinic schedules. You'll find these patients way more than you would like to, and we think that, oh, these are just taking the slot from a patient who does need us. These are sick patients. That low flow is actually associated with worse outcome, heart failure admissions and death. So, these patients do need our attention and what you can see here that the test that has been suggested to do this, either stress path or stress CMR with blood flow. So, if you're going to use, and in the US, there are less than 2030 sites that are doing CMR with blood flow, so technically, and there are still some technical, like, uh, modifications or fine tuning that's required on the, on the MRI site. So, PET is the modality that you're going to go and check for these blood flows and try to understand it. And coronary microvascular dysfunction is mainly, as we saw, failure, failure to adequately vasodilate. What we see here is that, These patients are not usually primary. It's usually they have one or more of these symptoms. So, it's either obesity, it's smoking, diabetes, renal failure, obstructive epicardial disease, Huff, some connective tissue disease, SLEs, scleroderma, rheumatoid arthritis, and then it's uncommon if somebody has none of the above, but we have our share of very few cases that have that. We even described this at the time of COVID that we saw that patients, right, post COVID, uh, we tested them, they had lower flow. It was associated with worse outcome, and this is a fellow who published this in JAC Imaging. But the good thing is that when we noticed is that once post COVID, once COVID is less than, sorry, more than 9 months, It just goes away. So, some of the strains were even different. So, some of the most virulent strains were actually giving more of this. But the good news is that at 9 months to a year time, it starts to fade away. So, probably one of the mechanisms, Mechanisms of what we call long COVID and some of these patients who have persistent symptoms. Some of it is real, and the good news is that usually by one year it starts to fade away because the endothelium does improve. So, given all of what I just told you, the US guidelines and the European guidelines now have advocated for cardiac path, I want to highlight, these are guidelines that are not written by imagers like me or others. These are guidelines written by, like, there is one imager on the writing group and the rest were primarily general cardiologists, interventional cardiologist who gave cardiac path class one indication for some, and, I showed you, for example, 2B, but clearly, uh, like it says that that is, if available in preference to is preferred to improve diagnostic accuracy, and we talked about the cardiovascular, uh, calcium score and also, uh, adding blood flow reserve and to diagnose microvascular dysfunction, but also to enhance risk stratification. These are from the chest pain guidelines and from the chronic coronary syndrome guidelines. To my surprise, the European guidelines are even went further, and they added three class 1 indications and one class 2A indication. So, finally, ASIC, which is a society that advocates for both NCT and PET, came in a little bit late in the game, but it's better to come in than never show up. And come up with this statement just came out like less than a month, uh, less than two months ago, and now this is kind of the statement. Cardiac path, if available, is now the preferred test for evaluating CAD on all patients. We're always kind of pushed, like, which patient should I send for PT, which patient is for PET. If you can get them to PET, For availability and insurance, go get them, and we're advocating with all the third party payers to accept this, but this is kind of, there is not a clinical scenario where you can say PET is not the preferred modality. Now, obviously there is room for other modalities, but the main thing is that, It is, based on all the evidence I've shown you and others, it is clearly has the highest accuracy. In the lower risk, probably CT and diagnosis of atherosclerosis becomes an important one, but as we go up on the risk strata, stratification, it becomes more of an issue. So what's happening in the country now, this is a group of work uh that published by some of my fellows. You can see that we're seeing national trends. This is from Medicare data, which we published last year. And this is what is the US doing right now in terms of SECT, uh, sorry, in terms of cardiac imaging for coronary disease. And what you see here is that SPECT is still the dominating factor. PET is growing, but not where we would like it to be, and then you have these other imaging modalities lagging behind. And what we've seen in the past 10 years, there is 37% decrease in SPEC, and then we're seeing about 129% increase in PET. So, PET is actually increasing, and now, uh, probably the rate is increasing because of its added value recognition and the, uh, guidelines, good reimbursement, and also the increased availability that's become happening. And this is partly also because the patients we are seeing are different now. You can see diabetes and prediabetes are skyrocketing. I'm sure you've seen that, and obesity and overweight is becoming an issue. And these older imaging modalities, including SECT, are not going to pan out to be a good tool when you have these, um, Uh, this kind of patients, uh, because no matter how much you do corrections or attenuation correction and others, there is still sometimes some limitation. But also the type of coronary disease we're seeing, and our colleagues in the cath labs have been kind of like advocating for that. You don't see now, like this type. A focal lesion that you just go dilate and get out and the rest of the vessel is fine. Most of what we are seeing is diffuse atherosclerosis. You're trying to see where that lesion, and that's partly because of the, uh, type, Of patients we are seeing, and there is a lot of microvasculature abnormalities, mostly in the obese patients, and there is also increased risk of events. So, with these type of tools, the current conventional tools that we've looked at have some limitations. And specifically SPECT is going to struggle with obesity, with obese patients, and if you're going to continue to do SEC, I've always just put this in 25, but I think even before that, we need to do much better with SEC in those patients that, unless we get access to, uh, PET, but if we're sticking with SECT, sometimes it's not going to be your best tool, but for some patients that you may be forced to do it, you have to do attenuation correction. You have to combine it with calcium score. And you have to try to use the lower dose protocols like stress only or use the newer cameras like CCT and others. I think this is very important, and those 1.2 or 1.3 million studies were done with SEC, they should be done with the higher standards. Otherwise, we are missing a lot of disease, and you saw the sensitivity data that I showed you in the beginning. Now, how is it happening in the US now in terms of geography? So there are about 660 centers doing cardiac path, and this is based on the Medicare data from 2021. So, not all of them are like, like, for example, we counted, like if you have it here in Centera, but also in one of your satellites, these count as two centers. And despite that, there are only 600 centers doing some cardiac path. Some of them are every day, some of them are a few days, but if you look here, you can see that, In your area, there is a lot of imaging deserts, and many of your patients are driving 50, 100, 150 miles to get to a PET center, so there are a lot of imaging deserts in the US that in terms of access to cardiac pet. And there are some real challenges why cardiac path, especially perfusion, is not available. And this is in part because to build the program, it does require a lot of putting a lot of pieces together. And in this review article, we kind of mentioned what are the barriers for cardiac path, like, uh, and then the, uh, potentially the steps for solution. Obviously, I don't have time to go over all of them. But I want to highlight that as of last year, there was only kind of one business model for cardiac path. You need to have good access to the machine. You need to have a large volume to do it, and then you get either a bidium generator or ammonia to do it. So, that's why you see most of these centers were doing, like larger volume. So, uh, although a center like, Yours, for example, do have the patient to kind of justify a dedicated pet and others. There are many practices in the rural areas or in some other smaller hospitals may not have access to that large volume of patients. To be able to do it. But now we have a new tool, a new tracer, which just got FDA approved, where you can order it by unit dose. So, even if you have a small number of patients and you have access to a PET scanner, you don't need to commit to a large volume. You can get this tracer. Which was just approved. It's F-18, like you get your, like FDG for cancer, you get this one and then you can go ahead and do the whatever cases you have. Uh, you need cardiac PET for. And this tracer actually is F-18, so technically it has superior image quality. You can even do exercise with it, which we were not able to do before, but if you do the exercise, you lose the blood flow. So, at this stage, we're trying to balance it. There are some research going on to try to come up with an estimate of blood flow with exercise, but that's a challenge still. And then you can just order from a pharmacy, whichever doses you need. So, technically, you're not going to require to have, like, one day you have 3 patients, you order doses for 3 patients. Tomorrow you have 6, you order for 6. The day after you have 1 dose, one patient, you order for 1. So, it kind of gives you flexibility for that. It does have some additional information, That it has, from a characteristics of the tracer, it is almost linear. So, the blood flow quantification is actually closer to linearity because its uptake is better than the medium, for example, or ammonia, and then the image quality is better. And I'll show you some cases from the trial that resulted in the approval of this, uh, Uh, tracer. This is a patient who had a SPECT study, and if you look at it, that's not unusual from what we see, but if you look at it, most of us will pass this as normal. In fact, in the trial, it was read as normal. And this is by PT from this tracer. Now you can see that there is a big inferior defect that you don't see on the other. So, you can see here this defect, which clearly indicate an RCA lesion. And in the trial, everybody went for cath lab and the patient has multiple lesions in the RCA, uh, obstructive lesions in the mid and distal RCA, as you see here. So, when looking at overall CAD diagnosis between this patient and all patients in this study had SPECT and PET with this tracer, and, With this one, actually, uh, you'll see that the patient had better accuracy with PET. Certainty was also good, and looking at it on every group, actually, it was better with PET compared to SPAC, and the image quality was much better. The radiation exposure, because it's F-18, it was a little bit higher, although now I'll show you, we come up with even a lower radiation exposure protocol. So, about a couple of years ago or 1 year and a half years ago, this tracer was approved. It's now available on the market. There are about 60 or 70 sites in the US that are doing it. We're lucky to be the first center to use it clinically in the US and we've done so far about 450 studies of it with it, and our experience has been very good. In fact, we have Uh, some patients were doing some research, the same patient undergoing the same tracer with rubidium, comparing it to rubidium, so you can see the same patient, you can see the impact on image quality. And we also quantified blood flow. You can see how the image quality look different between rubidium and flupiridaze, and the blood flow is closer to linearity because, so we see wider kind of differentiation between normal and abnormal. So, because it's a new tracer, it requires some training, uh, uh, like, even among the experts who read for other tracers, At Anik, we kind of very focused on quality and we put out, like, these are three on YouTube now. You can look in there. We did three webinars specifically to look at this. I had the pleasure of actually leading these webinars to try to indicate how can you read these and what are the normal variants, what, what you, should you call as a defect, what you should not call as a defect, and these are available and, If this is of interest, like you're going to go in with the tracer, this tracer, you need to go, even if you're a pet reader, you need to go and listen to this, and we had, like, almost 300, 400 live attendee on this that you need to gather that information because there are, each tracer has its own nuances. And one thing that I want to just highlight, when this tracer was approved, this was a protocol that it came out with. I'm not going to go through the details, but it was a long protocol. So, technically, the protocol will require the patient to be on the table 45 minutes, and if, Add to it the time that they're putting the patient and the time they're taking them, it's about an hour to an hour, 15 minutes, which is not our usual rubidium slots. Our rubidium protocols are like 2025 minute kind of protocols. So the first thing we did is like, you know what, let's go ahead and, I'm not convinced that this is the right protocol for this tracer, and we come up with our own Houston Methodist protocol that we published on, and we have, this is a 22 minute protocol. What we did, actually, is that we lowered the radiation dose. So, you can see here, we kind of came up with lower protocol numbers, and this will allow us to even lower the, um, Radiation exposure for these patients, and now even the vendor allows you to order these lower doses based on this publication, and now you can even lower the cost of the procedure, but also lower the radiation exposure to the patient, especially if you have a digital camera that does not require these higher doses. So, with this, we've shown that this is highly accurate. In fact, out of these 400 patients using this protocol, about 100 went to the cath lab because they were abnormal, and almost all except one, which I think it's Zoca, had obstructive disease detected. So the accuracy of this protocol is very good for that. So, I think I've shown you how perfusion PET is evolving. Now you have multiple options to choose from, whether you can do it on a high volume, but even in a center like yours where you have multiple satellites, if they have a PET scan, you can order like one small one. If you have a larger volume, you have multiple other, Options. You can even like send a mobile PT that can do some of these procedures. So, we do need to improve access to cardiac path to kind of, like, work on that position statement that we said cardiac path, if available, is the, uh, preferred modality. So availability is obviously, Uh, the physical availability, but also at the same time, looking at the availability from, um, like insurance and, and we continue to do advocacy to kind of expand the adoption of cardiac path for otherwise. In the coming 10 minutes, I'm just going to touch base quickly on some of the additional protocols we do, uh, with PT, which is now about, like, as I said, between 30 to 35% of our volume. And you can see here, we're still doing viability. I think overall interest for viability is coming down because of all the data that has come out in terms of MRI literature and others, but we still, like, if they need it for CTO intervention for otherwise, we do do a lot of viability, maybe once, like between 2 to 5 a week, and then, uh, this is, uh, Very helpful in different clinical scenarios and based on prior meta analysis, nuclear techniques and specifically FDGPT is the most sensitive to detect viable myocardium. While dubutamine echoes, specifically the biophysic response of the, Uh, more specific for this. Uh, amyloidosis is obviously an area where there is a lot of growth in this field, not specifically in PT. I know that we talked yesterday about PYP imaging and otherwise, but now, like, I want to just put in a plug in that we're moving away from the heart toillateral ratio to specifically look at SPECT and SPECT CT. And you, obviously, to make a diagnosis, you need to exclude AL amyloidosis and look at it on PYP imaging. But now we are learning that there are some cases where the MRI could be normal. This is a case report that just came out on circ imaging, where the MRI is normal, even ECV, they measured on different segments, 20 to 32. And then the patient had the PYP and the PYP was on the spot, but not clear. And now we have PET tracers, two PET tracers completed phase three trials, and they just got locked, the data got locked. And we expect the results to be out in the coming year or so, or maybe less. And these are newer tracers that you're still going to help you to identify these patients with amyloidosis, despite having multiple other negative testing. And this patient, Actually did have biopsy and it was diagnosed with cardiac amyloidosis on biopsy, despite negative PYP and others. So, this is like probably going to become like one of those areas where you start with PYP, but if the PYP is negative, but then you still have suspicion, And you've ruled out AL amyloidosis, this might be a tool and expect it to be, I'm expecting this tracer to become approved in the coming year or so, and then this would be an additional kind of procedure for your heart failure colleagues. The interesting thing is that the hope for these, all these other imaging modalities, we do not have a good tool to assess if the patient is responding to therapy or not. So, we're mainly using clinical symptoms. But now with this tracer, you think of it like cancer, where you do, diagnose the cancer, you get a baseline PT, then you give them chemotherapy, then you repeat the PET. I think with these PET tracers, we're going to end up doing the same, where once we diagnose amyloidosis, we get a baseline PET, then give them tefemidus or some of the new, uh, depleters or, uh, Uh, stabilizers and then go ahead and get another PET later on to see if they're responding to therapy, a more objective way to assess in addition to others. Another area that we see a lot of growth with PET is the actually cardiac inflammation and sarcoidosis. Obviously, for this situation, we start with MRI. If the MRI is negative, then the yield is very low, but if the MRI is positive, like you see here, then this is where we would like to get an advanced imaging modality like PET to look for inflammation, where we see a perfusion defect and then we see FDG uptake in that segment. And in some patients, you can see that we can detect it in the ventricle. We can detect it in the atrium, and these patients do have like atrial arrhythmias, ATs and others. This patient specifically had like 20 inappropriate ICD shocks in one day, all from atrial tachycardia. You can also look for extra cardiac amyloid, uh, sorry, uh, sarcoidosis or inflammation. I just want to highlight that it is very important to prepare these patients well. We don't want to overcall the disease. And until recently, there was no other way other than just do it trial and error and identify if the patient has, uh, uptake that you think it's abnormal or not. And obviously, if the center is not doing too many of these studies, there were many patients mislabeled as active inflammation. They were not. OK. So this case was kind of like one of those cases that opened our eyes, where the MRI was normal. You can see here, there is a small scar there, but the uptake is so diffused that I'm like, it doesn't make sense. So we told the patient, nope, it doesn't sound like you have this. Why don't you go ahead and have repeat study after strict, more strict, Um, preparation and now the study is abnormal, uh, study is normal, so the patient doesn't need to be on steroids and all these side effects from these. And the question is, can we do better? Can we just, like, figure out a way that we can tell if the patient is well prepped or not? So, we've been doing some of these studies and we finally, I think, got to the sweet spot where we'd come up with a test called beta hydroxybutyrate, same one you use for DKA and others. So, we measured it and what we noted that if the beta hydroxybutyrate is below 0.2, the chances of the patient being prepared is extremely low, like 20 to 25%. Once they are between 0.2 and 0.4, we noted that they're like almost flipping a coin. And, uh, obviously, 0.39 is very close, and once we got to the 0.4, at least in our study, we saw that it is actually indicating that the patient is well prepped. This data has been validated by three other studies from three other, Centers and they all come up with similar numbers. Now there is even a point of care test that we need to validate its values. So, like you do creatinine before CT, you just check or do blood sugar. Now you can do this. And if the patient is below 0.4, Then you could run the risk that the study is not diagnostic. Now, it doesn't mean that everybody is going to be non-diagnostic. Here I'm showing you a patient where the beta hydroxy was 0.13 and non-diagnostic. Then we repeat it at a higher beta hydroxy and now it's normal. But look here, for example, you have a patient with 0.14 and he was, this patient was diagnostic and it was negative. So, it's probably one of those that are in this group here. So, We decided for the patient's sake, radiation exposure and everybody, if their beta hydroxy is below 0.4, we try not to do it and try to at least have them fast longer and try to come up with an adequate, uh, strategy. And it's very helpful to allow us to follow up on the response to therapy here, so we can quantitate how much inflammation is in the heart. So you can see here all this red areas abnormal. Now it's much smaller and we can look at this. But also, sometimes PET has a diagnostic role despite all these imaging modalities. This is a case we saw recently. 74 year old man with dizziness. He's got history of hypertension. The patient came in the hospital. First EKG showed left bundle, first degree of block in the hospital, progressed to type 2 and then complete heart block. So, they went ahead and put in a pacemaker and transferred to our facility. So, the patient did undergo MRI as per our protocol. So, you can see the MRI here. There is some regional wall motion abnormality that you see there. But you can see that there is nothing really jumping at you when looking at this other than the mild regional wall motion abnormality. When we look at the LGE, and this is a study that many of us looked at it, stared at it before and after, and tried, like, what I call anything positive there. And I showed this in SCMR and I asked people, can you raise your hand if you see any abnormal. There were barely one or two. And you can look here. This is the pacemaker that was inserted. Some people thought this may be, may not be, may be here. Like, it's nothing that really jumping at you to tell this. But we did the, uh, black blood and now we start to see some lymph nodes in the chest, like, uh oh, there is something there. And obviously, the clinical story is very suspicious. So, we said, the leading physician said, like, the clinical story is suspicious. MRI is normal. Maybe like he ended up, after looking at it 100 times, amending his report to call it 1% of the, uh, basal septum. But again, it's not extreme, but the lymph nodes, you can see them on the MRI, it's kind of like now concerning. So, we did an FTG PET for this patient, and you can see that specific area did light up. There is some in the lateral wall, but most concerning, all these lymph nodes lit up like hell there. If you look at it, all these lymph nodes were active inflammation. So, technically that progression to complete every block was truly active inflammation. Very unusual at 74 to have the first presentation. But it does happen and it shows you the good diagnostic accuracy there. And this patient actually did, was put on high dose steroids and then came back to us six months later, and now there is no more uptake in the basal septum where we saw the uptake before. Now, and the patient is rarely paced when you do the device interrogation. So, I mean, I'm not saying that initial decision to put the device was not appropriate, but, Obviously, these patients could have recurrent inflammation and could progress. And now we have tools to kind of merge them so that we can figure out some LGEs, scars that are not inflammation and some of them are inflammation. Keep in mind that FDG uptake in the heart is not specific to sarcoid. We have multiple others. We've seen it with giant cell, all these eosinophilic, lymphocytic. We see it with myocarditis, cardiomyopathy. Amyloid, fibris, HCM, and most recently we're seeing more and more from lamin and erythmogenic. So, we are doing genetic studies on every patient that we detect actually positive PET, and we're finding out many of them are not actually sarcoid, but rather genetic cardiomyopathies. So, these patients tend to have low grade inflammation, And we've detected many with lamb and cardiomyopathy, specifically, it was the suspicion triggered by NFTGPT. Sometimes you can even see it in the pericardium, so you can see in this pericarditis case where on the MRI you see this uptake, you can see this. And we can look also at giant cell, sorry, on takayaso and large vessel inflammation. So these are sometimes cases that come to us, and when they treated, they become less inflamed and now more calcified. I think the newest application is becoming infection, which is now has class one indication in the European guidelines, American guidelines are lagging behind. And you can see here that, you can get this focal intense and heterogeneous uptake that you see here. So, this is kind of the hallmark. We have many cases that were potentially not called by echocardiography for various reasons, poor image quality, not very well seen, but you can see this abscess there that lights up big time. Can see also these two here that are lighting up. I'll look at the focal intense and heterogeneous. So, sometimes it may be a little bit challenging to, when it is so homogeneous, that could be the, um, the surgical glue that is lighting up there or partially treated sometimes, but homogeneous uptake, so this, Becomes more like a consult. You need to look at all additional imaging modalities, TEE, sometimes CT to kind of come up with this. But for native valve endocarditis, for whatever reason, it has very low sensitivity, so we don't use it for native valve. We primarily use it for prosthetic valve infections, and we have, uh, very high, for this difficult condition, very high sensitivity and specificity. We also use infection imaging for LADs, as you might imagine. Our center is one of the, uh, leading centers in heart transplant. We have a lot of patients on destination therapy. These patients are very difficult to identify infection in the LAD, and there is no better than, for example, you can see here, this whole outflow pump, uh, catheter is infected. Sometimes it's in the drive line and it's affecting, uh, this. So, when you look at them, you can see now the new criteria clearly telling you that this PET CT is actually part of the criteria. PET CT in the European, it is part of the new new criteria. And you can see here that CTA and when combined with PET, for example, has class one indication in the European guidelines among patients that you're still suspicious and not very clear after doing, um, Uh, after doing, uh, uh, like, for example, echocardiography and you're still suspicious for that. So, I hope I've shown you all these potential applications, but keep in mind that, uh, there are a whole, like, menu. I think most of us are doing a lot of MPI, but these are growing applications and, They help you a lot in terms of managing complex cases that will be needed to, uh, advance the care of these patients. Keep in mind that we're not saying here we're going to do PEET for everybody. We're going to still look at the patient and there are, you can see I've shown you many cases where we combine it with other, MRI or CT and other assessments to give what the patient needs, which is the patient first approach rather than a modality first approach where we do the right test for the right patient using, for the right indication and using the right tools that we are, have available. Thank you very much, and I'm happy to take any questions. Published April 30, 2026 Created by
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