1 00:00:05,570 --> 00:00:11,180 We will talk today a bit about how we can get different images of the heart to tell us different 2 00:00:11,180 --> 00:00:15,950 things about what's going on inside the hearts and not just looking at heart anatomy and function, 3 00:00:15,950 --> 00:00:22,070 but also looking at what's going on inside the heart cells to detect different types of cardiac diseases. 4 00:00:23,600 --> 00:00:28,969 So cardiovascular disease is one of the major causes of death in the UK unfortunately. 5 00:00:28,970 --> 00:00:37,010 So we have quite a few cases of cancer leading to death, 28% of death attributed to cancer. 6 00:00:37,160 --> 00:00:40,760 But just shortly after that, 26% attributed to cardiovascular disease. 7 00:00:41,000 --> 00:00:45,230 And that's things like myocardial infarction, heart failure and such like. 8 00:00:45,530 --> 00:00:51,950 So it's very common. So heart attacks, everyone has heard of sudden, sudden pain in the chest, 9 00:00:52,280 --> 00:01:00,740 calling 99 and and heart failure as a more kind of slow progressive disease and why there are imaging modalities available to detect those. 10 00:01:01,020 --> 00:01:05,899 There's still a lot of improvement to be made to really get the right treatment for the patient because 11 00:01:05,900 --> 00:01:11,030 we're moving more and more towards personalised medicine where it's not one shoe fits all sort of approach, 12 00:01:11,030 --> 00:01:15,890 but more what is actually happening in this person and what is the best treatment for this particular person. 13 00:01:16,040 --> 00:01:19,520 And we need good imaging to to to choose basically what we do. 14 00:01:20,690 --> 00:01:25,790 So this is just very simple sort of cartoon images of the heart, just so that everyone knows what we're talking about. 15 00:01:25,790 --> 00:01:32,930 So that's sort of showing the heart from the outside with the aorta as the major vessel in the heart that pumps the blood around the whole body. 16 00:01:33,290 --> 00:01:39,410 And then the blue thing here is what brings the deoxygenated blood into the left and right lung for oxygenation. 17 00:01:39,740 --> 00:01:45,620 And if you take a cross-section through the heart, we can see inside the heart. So this is the right chamber of the heart, the right ventricle. 18 00:01:45,830 --> 00:01:49,850 And that pumps blood through this pulmonary artery into the lungs for oxygenation. 19 00:01:50,240 --> 00:01:57,080 And this is our left ventricle, the left chamber of the heart, where we get blood, blood pumped through the aorta, into the general circulation. 20 00:01:57,080 --> 00:01:58,250 So for the rest of the body. 21 00:01:59,150 --> 00:02:04,730 And the question is, I don't know how many people know really exactly how the heart works and how that gets pumped around. 22 00:02:04,940 --> 00:02:07,400 But you can sort of compare that to a mechanical pump. 23 00:02:07,700 --> 00:02:13,549 So fluid flows into through one pipe and then does mechanical pump, turns it around and pushes it out. 24 00:02:13,550 --> 00:02:17,780 Another pipe. Right. And if you now look at the heart, it's not that dissimilar. 25 00:02:18,050 --> 00:02:24,320 So we have blood that comes through through one pipe and then gets pushed through another pipe, and that happens by muscle contraction. 26 00:02:24,530 --> 00:02:29,089 So our mechanical pump here is the heart muscle itself keeps beating throughout the lifetime just 27 00:02:29,090 --> 00:02:33,500 to make the circuit complete so that we get deoxygenated blood into the lung for oxygenation, 28 00:02:33,830 --> 00:02:39,190 back through the left atrium, into the left ventricle, and out through the aorta, into the rest of the body. 29 00:02:39,200 --> 00:02:46,849 And that just keeps going and keeps going and keeps going. And one way of looking at dysfunction in the clinic is with echocardiography. 30 00:02:46,850 --> 00:02:50,750 So that's an ultrasound of the heart. It's reasonably cheap, very widely available. 31 00:02:51,080 --> 00:02:55,549 And you can see some sort of blood movement across these different chambers here. 32 00:02:55,550 --> 00:03:02,150 But the images aren't that great and it's mostly 2D. So it doesn't really give us that much information about what's really happening in 33 00:03:02,150 --> 00:03:07,070 3D and not really much sort of information about the actual cells in the heart. 34 00:03:08,270 --> 00:03:13,639 One other very powerful technique to look at the heart with is magnetic resonance imaging and this different 35 00:03:13,640 --> 00:03:18,950 approaches using this machine to to give different information about what's going on inside the heart. 36 00:03:19,250 --> 00:03:24,110 And this is what I'm now going to hand over to Justin, who will talk a bit more about MRI and then I'm back. 37 00:03:25,280 --> 00:03:28,700 Yes. So just not being biased. MRI is one of my favourite imaging modalities. 38 00:03:29,120 --> 00:03:35,960 I also work on it. So so with MRI, what you can do is you can actually acquire any kind of cross-section through the body. 39 00:03:36,110 --> 00:03:39,349 So you can acquire slices that are kind of like this. 40 00:03:39,350 --> 00:03:47,330 You can acquire slices that are centred. And so in the heart, what we usually do is we try to align to the natural axis of the heart. 41 00:03:47,870 --> 00:03:52,189 And so here, this cross-section here, that's what we call the short axis. 42 00:03:52,190 --> 00:03:56,300 And that's usually the most common way of looking at the heart with the MRI images. 43 00:03:56,930 --> 00:04:03,830 So so the this cross-section here shows the two chambers to two lower chambers. 44 00:04:03,950 --> 00:04:08,420 So you see the left ventricle here and the right ventricle here. 45 00:04:08,690 --> 00:04:13,970 And because left ventricle has to work hard to pump the blood to the rest of the body, 46 00:04:14,150 --> 00:04:17,210 whereas the right ventricle just has to pump the blood to the lungs. 47 00:04:17,720 --> 00:04:26,570 So the left ventricle is more muscular. And that's characteristic of how hard the heart that the different parts of the heart have to work. 48 00:04:27,350 --> 00:04:33,170 And so the heart has is contracting and relaxing, contracting and relaxing. 49 00:04:33,320 --> 00:04:40,399 And so when it's fully relaxed, we call that diastole. And this is kind of representation of when the heart is fully relaxed. 50 00:04:40,400 --> 00:04:48,320 So the the left ventricle, the wall is very thin, whereas when the heart is fully contracted, that's called systole. 51 00:04:48,500 --> 00:04:58,190 And that's where the left ventricle has squeezed to its maximum position to expel as much blood as possible to the aorta and to the rest of the body. 52 00:04:59,120 --> 00:05:04,640 And so the difference between the fully expanded and the fully contract. 53 00:05:04,740 --> 00:05:11,670 It states that's called the ejection fraction and that that represents how effective the heart is at pumping blood around the body. 54 00:05:11,790 --> 00:05:16,350 So the higher the ejection fraction, the more efficient the blood at the heart is pumping the blood. 55 00:05:17,100 --> 00:05:20,219 So in MRI, what we look at is this cross-section. 56 00:05:20,220 --> 00:05:24,090 So we look at the health of the left and the right ventricles. 57 00:05:24,870 --> 00:05:35,370 And you can tell if the left ventricle in particular is thicker than usual, then that indicates that it's working a lot harder to do the same job. 58 00:05:35,610 --> 00:05:44,740 And so that could indicate early an early sign of heart failure. And so I'll switch quickly to the the video, which is on the desktop here. 59 00:05:45,220 --> 00:05:49,870 So here we have a four dimensional view of the heart. 60 00:05:50,090 --> 00:05:58,510 So, so here we have the the heart going from the top to the bottom. 61 00:05:58,510 --> 00:06:03,430 So from the what we call the base at the top near where the aorta comes out. 62 00:06:04,000 --> 00:06:09,220 And then we move down the heart along its natural axis of symmetry, down to the bottom. 63 00:06:09,230 --> 00:06:11,110 So here that's the top of the heart. 64 00:06:11,620 --> 00:06:20,770 And as you move down, you see the the left ventricle here in the circular shape and then the right ventricle here on the side. 65 00:06:21,310 --> 00:06:25,630 And then as you move towards the apex of the heart of the bottom of the heart, 66 00:06:26,200 --> 00:06:31,630 you start to see the the chambers getting never work as the heart is kind of a bit of a cone shaped. 67 00:06:32,320 --> 00:06:35,230 And then here you can see that the bottom of the heart. 68 00:06:35,440 --> 00:06:40,870 And so so just as a reference, if you take the other plane, which is which we can do easily with MRI, 69 00:06:41,320 --> 00:06:45,970 if you take the other cross-section, kind of like cutting through the heart the lot the long way. 70 00:06:46,600 --> 00:06:50,380 So this is the top of the heart. So that's that corresponds to this image here. 71 00:06:51,010 --> 00:06:58,149 And then this is the bottom of the heart. So as you go down from the top to the bottom, that's where we're going from this from left to right. 72 00:06:58,150 --> 00:07:01,870 And then here that's towards the bottom of the heart. So it's so this apex here. 73 00:07:02,560 --> 00:07:04,180 And so this is a relatively healthy heart. 74 00:07:04,450 --> 00:07:12,700 So you can see the the walls are contracting, the left ventricle in particular, so that this round part here, it's contracting uniformly around. 75 00:07:12,700 --> 00:07:17,350 So it's doing quite well. And that's pretty typical of of a healthy person. 76 00:07:18,380 --> 00:07:26,180 So now we will look at what happens when you have a heart attack. 77 00:07:26,510 --> 00:07:34,610 So so heart attacks happen when one of the arteries that supply the heart itself becomes blocked. 78 00:07:34,790 --> 00:07:39,460 So the heart requires a lot of blood in order to continually contract it and expand. 79 00:07:39,620 --> 00:07:46,130 And so the blood flow that gets diverted from the aorta into the heart. 80 00:07:46,670 --> 00:07:51,800 And so there's branches of arteries that sometimes can become clogged. 81 00:07:52,370 --> 00:07:57,980 And if there's a blockage, then that part of the heart no longer receives blood and it can become injured. 82 00:07:58,610 --> 00:08:03,710 And so usually the symptoms are chest pain and shortness of breath. 83 00:08:04,190 --> 00:08:08,900 And that's when you call nine and nine. And so the ambulance will take you to the John Radcliffe Hospital. 84 00:08:09,350 --> 00:08:14,060 And then we can do imaging on the heart. 85 00:08:14,540 --> 00:08:20,690 And so, again, I'll switch to the videos just to show you what the heart looks like after a heart attack. 86 00:08:24,040 --> 00:08:30,160 So here you can see. So this is the left ventricle and this is the left atrium. 87 00:08:30,910 --> 00:08:37,540 And what you can see here is the other video showed a nice ring that contracted and expanded, 88 00:08:37,840 --> 00:08:42,220 whereas here you can see the side of the heart that's not really moving. 89 00:08:42,880 --> 00:08:47,920 And also the top the left atrium that this is not really contracting either. 90 00:08:48,460 --> 00:08:50,860 So the left left atrium usually is a lot smaller. 91 00:08:51,280 --> 00:08:56,530 But here, because the left atrium is not as efficient at expelling the blood into the left ventricle, 92 00:08:56,680 --> 00:09:00,820 and the left ventricle is not as efficient pumping the blood out of the aorta. 93 00:09:01,690 --> 00:09:05,349 So there's a back pressure. So it really comes down to plumbing. 94 00:09:05,350 --> 00:09:09,580 So there's this back pressure. And so that causes the heart to expand. 95 00:09:10,360 --> 00:09:17,920 And so normally the heart can adapt is a very versatile organ. 96 00:09:18,640 --> 00:09:25,240 But this is this is this can lead to heart failure if the heart becomes too over pressured. 97 00:09:25,320 --> 00:09:31,840 So when it's working too hard to to to pump the blood around. And this is just another view. 98 00:09:32,320 --> 00:09:36,780 So again, you see this bottom side of the heart is not really contracting. 99 00:09:36,790 --> 00:09:42,310 So most of the work is just done on the top wall. And here as well, the left atrium. 100 00:09:42,600 --> 00:09:47,320 This part is not really contracting. And so this is a bad sign. 101 00:09:48,070 --> 00:09:54,250 And there are there are treatments to to hopefully restore some function to parts of the muscle. 102 00:09:55,470 --> 00:09:58,470 Um, and so, um, next, 103 00:09:58,470 --> 00:10:06,180 so I'm going to pass it back to Kristen and she'll talk about some new techniques that we can use for early detection of parts of the heart 104 00:10:06,330 --> 00:10:12,300 that might be in trouble versus part of the heart that can recover so that we can give the most appropriate treatment to the patient. 105 00:10:14,070 --> 00:10:19,170 So so far we've just talked about function, but unfortunately with a lot of diseases such as myocardial infarction, 106 00:10:19,170 --> 00:10:24,420 it can take some time to really manifest itself as a difference in output from the heart. 107 00:10:24,420 --> 00:10:27,690 So it takes some time until the heart is sort of scarred when you notice that 108 00:10:27,690 --> 00:10:31,620 there isn't such a great movement of the heart muscle anymore on heart failure, 109 00:10:31,620 --> 00:10:35,640 it takes quite some time for symptoms to manifest because the heart is very good at compensating. 110 00:10:36,060 --> 00:10:39,629 So a better way of assessing someone's cardiac health would be to look a bit 111 00:10:39,630 --> 00:10:42,780 more insight themselves and see what's actually going on on a molecular level. 112 00:10:43,260 --> 00:10:46,200 And for that, we're very interested in cardiac metabolism. 113 00:10:46,200 --> 00:10:50,550 So that means how the heart takes up different types of fuel sources and makes energy from it. 114 00:10:51,450 --> 00:10:56,280 And that's essentially leading to for the heart to be able to contract for lifetime. 115 00:10:56,820 --> 00:11:00,090 So energy generation through metabolism is incredibly important. 116 00:11:00,540 --> 00:11:05,819 And it turns out that the heart to heart kind of likes all different types of food for energy generation, 117 00:11:05,820 --> 00:11:13,559 but it preferentially uses a mix of fat and sugar with a slight preference for fat, but it needs that sort of versatility to really work properly. 118 00:11:13,560 --> 00:11:18,090 So that's why I think showing a little a little scale, you know, you both need the fat and the sugar. 119 00:11:18,930 --> 00:11:22,229 And if you now zoom inside the heart to a cardiac muscle cell. 120 00:11:22,230 --> 00:11:28,050 So this is a heart muscle. So this green thing here represents the powerhouse of the cell, which is called a mitochondria. 121 00:11:28,860 --> 00:11:34,620 This is where oxidative metabolism happens when you have oxygen available and you can fully burn fuel so that you can get 122 00:11:34,620 --> 00:11:41,129 the maximum energy if oxygen is not available and you can't get that much energy out of fuel sources and in a normal, 123 00:11:41,130 --> 00:11:45,390 healthy heart, we want to have, like we said, sugar in the form of glucose and also fat. 124 00:11:46,350 --> 00:11:55,049 And all of the sugar metabolism goes through a key central metabolite pyruvate and that can lead either lactate or lactic acid, 125 00:11:55,050 --> 00:11:58,140 which can be produced when there's no oxygen available, 126 00:11:58,410 --> 00:12:05,460 when there's oxygen available and we can fully oxidise sugar and generate bicarbonate, which is sort of the soluble form of carbon dioxide. 127 00:12:05,940 --> 00:12:13,080 So what happens is basically those fuel sources go inside the mitochondria and get fully oxidised, generate energy for a healthy beating heart. 128 00:12:14,550 --> 00:12:18,600 Now, this picture changes slightly, like I said, when we don't have oxygen available. 129 00:12:18,600 --> 00:12:22,139 So imagine there's no oxygen available because either we have had a heart attack 130 00:12:22,140 --> 00:12:26,400 so this ischaemic myocardium or we're hypoxic because we had high altitude, 131 00:12:26,400 --> 00:12:34,050 for example, even though we shouldn't go that high for that really to manifest itself in massively changed metabolism. 132 00:12:34,950 --> 00:12:39,629 But yes. So what happens then is that basically we cannot use fat at work because fat goes right 133 00:12:39,630 --> 00:12:44,340 into the mitochondrion and needs that oxygen very vitally for for for its metabolism. 134 00:12:44,340 --> 00:12:49,920 It can't go via this pathway. So what we can do is use that glucose and chuck it into that lactic acid. 135 00:12:50,280 --> 00:12:54,810 And I mean, acid is bad, right? Too much of it is fat acidify our blood. 136 00:12:55,020 --> 00:12:58,770 It's not very good for us and certainly isn't very good for the myocardium either. 137 00:12:59,070 --> 00:13:06,690 And it doesn't produce that much energy. So you can see from this animation heart doesn't pizza one so that's that's a bad sign and conversely there's 138 00:13:06,690 --> 00:13:15,089 also scenarios where we could rely more on on on fat for energy generation and we can't use any glucose. 139 00:13:15,090 --> 00:13:17,549 So there can be changes to the way that you take up glucose. 140 00:13:17,550 --> 00:13:21,960 For example, if if we don't have enough insulin around like in a diabetic person, we don't have insulin. 141 00:13:22,170 --> 00:13:31,049 We need insulin to get sugar into the cells. So if that's prevented, then we fully rely on fats and why we can oxidise them into mitochondria. 142 00:13:31,050 --> 00:13:36,150 We don't get that maximum amount of energy that we would if we had both nutrients available. 143 00:13:36,510 --> 00:13:43,709 So that's another sign that something's not quite right. So just to summarise, again, for metabolism, there's different diseases. 144 00:13:43,710 --> 00:13:48,480 So in a in a myocardial infarction, we would rely more on sugar for anaerobic metabolism. 145 00:13:48,480 --> 00:13:52,740 So no oxygen available, we generate acid, not enough energy generation and acid is bad. 146 00:13:53,730 --> 00:13:59,709 If we have more energy requirements for sugar than fat, then we instead of heart failure. 147 00:13:59,710 --> 00:14:06,120 So when the heart starts to fail, then it becomes less able of really using the fats efficiently. 148 00:14:06,480 --> 00:14:10,709 And then when we are relying more on fats than on sugar, then we can have a diabetic heart. 149 00:14:10,710 --> 00:14:16,500 So the diabetic heart again lacks insulin, can take up sugar as well, and relies more on on fatty acids. 150 00:14:16,680 --> 00:14:23,610 All of those diseases are associated with inappropriate energy generation and that manifests itself in change function. 151 00:14:23,970 --> 00:14:27,209 But the thing is that if you could catch that very early on, 152 00:14:27,210 --> 00:14:33,750 so if you could see very early changes in fewer and fewer choice and how those fuels metabolised inside the cell. 153 00:14:33,750 --> 00:14:37,319 And then there's a time when where we could offer some treatment to improve that 154 00:14:37,320 --> 00:14:41,129 before we actually get those functional changes where you start becoming breathless, 155 00:14:41,130 --> 00:14:44,460 you can't really do your normal day to day day life anymore. 156 00:14:44,730 --> 00:14:50,550 So that's where the multidisciplinary effort comes in. So in our lab we have physicists, chemists, vets, medics, 157 00:14:50,790 --> 00:14:54,990 all sorts of different people that put together expertise to sort of try to tackle this problem. 158 00:14:55,770 --> 00:15:02,250 And Justin is now going to introduce a new technique that we can use to look at this metabolism inside the cells in a living person. 159 00:15:02,880 --> 00:15:09,330 So and so normally in M.R imaging, you look at water because the water is the most abundant molecule in the body. 160 00:15:09,510 --> 00:15:13,630 And so you can get nice images of structures like. How the heart looks. 161 00:15:13,900 --> 00:15:22,160 But in order to look at function, we want to look at fuels such as sugars, and those are usually present at lower concentrations in the body. 162 00:15:22,420 --> 00:15:26,140 And so what we would like to do is to increase the amount of signal that we can get. 163 00:15:26,740 --> 00:15:34,330 And so this is governed by thermodynamics. And so thermodynamics says at body temperature, you don't really get much signal. 164 00:15:34,330 --> 00:15:40,060 And that's why when you go inside a magnet, you don't stick to the magnet because we don't become strongly magnetised. 165 00:15:40,690 --> 00:15:49,000 So the trick that we play is we would like to put the system out of thermal equilibrium in order to get up to 10,000 times more signal. 166 00:15:49,540 --> 00:15:55,360 So how that's done is you can imagine the molecules as little bar magnets. 167 00:15:55,630 --> 00:16:05,020 And so what we do is we put the bar magnets into a strong magnet, and that aligns the magnets either with or against the magnetic field. 168 00:16:06,190 --> 00:16:09,579 And then we add some some electrons. 169 00:16:09,580 --> 00:16:13,840 So that's kind of where the source of the additional magnetisation will come from. 170 00:16:14,500 --> 00:16:20,390 And then we cool the whole thing down. So we cool it down so much that it's very close to absolute zero. 171 00:16:20,410 --> 00:16:23,709 So just below one, Kelvin, we're not engaged anymore. Yeah. 172 00:16:23,710 --> 00:16:26,890 So this is in. So this is in a machine called a polariser. 173 00:16:27,790 --> 00:16:33,399 And and so what happens is all the electrons, suddenly they align with the magnetic field. 174 00:16:33,400 --> 00:16:40,870 So they all point up. And what we want to do is we want the the molecules as well to point all point up. 175 00:16:41,110 --> 00:16:48,999 And so we use microwaves to jumble up the system so that we, you know, we flip an electron, but then we flip a molecule up. 176 00:16:49,000 --> 00:16:54,910 And so by doing this for about 3 hours, we can actually increase the amount of signal that we get. 177 00:16:55,300 --> 00:16:58,570 And this is basically fighting against thermal dynamics. 178 00:16:59,290 --> 00:17:01,240 But in the end, thermodynamics always wins. 179 00:17:01,630 --> 00:17:07,390 And so we have to act quickly before the system goes back to thermal equilibrium and we lose all the signal. 180 00:17:07,900 --> 00:17:13,300 And so what we do is we quickly melt it. And that's at and after we melt it, that's when we inject into the patient. 181 00:17:13,990 --> 00:17:23,350 So just to give you kind of a an idea of how this process is done, we have a video of how we prepare the sample. 182 00:17:27,430 --> 00:17:30,970 So this is the polariser. So this machine here, this is a strong magnet. 183 00:17:31,210 --> 00:17:37,390 And what it's what we're doing here is we're about to insert the stick that has the hot water inside. 184 00:17:37,510 --> 00:17:41,409 So this stick has hot pressurised water. And so the sample is inside. 185 00:17:41,410 --> 00:17:45,790 It's very cold. And so when you stick the stick in and then you release the pressure, 186 00:17:45,970 --> 00:17:49,840 the water goes in, quickly melts it, and then shoots it back up into the into the pot. 187 00:17:49,990 --> 00:17:55,030 And then you have to act very quickly. So you run. So you take it into the syringe, you run and then you inject. 188 00:17:56,020 --> 00:18:01,659 So you inject this into a person. And then what you can do is you can see the signal that comes out. 189 00:18:01,660 --> 00:18:08,160 And that's that's that's a signal that we use to create our images. And so what can we get with this? 190 00:18:08,400 --> 00:18:15,360 So we can get we can look at the different products of of the sugar. 191 00:18:15,540 --> 00:18:19,559 So as Kirsten said. So this this pyruvate, 192 00:18:19,560 --> 00:18:25,740 the sugar can either go down the the oxidative metabolism route so you get CO2 193 00:18:25,740 --> 00:18:30,360 and bicarbonate or you can go down the non oxidative so you can get lactic acid. 194 00:18:30,570 --> 00:18:36,150 So if we want to focus on looking at bicarbonate, what we can do is we can acquire signal. 195 00:18:36,630 --> 00:18:46,650 So as as this goes between bicarbonate and lactate, we can look at the the various signals and luckily they show up at different frequencies. 196 00:18:46,770 --> 00:18:48,480 And so they're like radio stations. 197 00:18:48,990 --> 00:18:58,650 So what we can do is we can tune our detection equipment to the right station to look at the different products of of this metabolism. 198 00:18:58,890 --> 00:19:03,510 And you can get images like this. So so basically what we're seeing is sugar. 199 00:19:04,170 --> 00:19:07,530 So this image here being converted into carbon dioxide. 200 00:19:08,010 --> 00:19:13,920 And so the sugar mostly shows up in the chamber because it's mostly in the blood, but it gets uptake in by the tissue as well. 201 00:19:14,520 --> 00:19:20,190 And you can see here in this healthy subject, you see a nice ring of carbon dioxide. 202 00:19:20,430 --> 00:19:23,520 And so this indicates that the heart is functioning nicely, 203 00:19:24,120 --> 00:19:29,730 that it's contracting and very active and uniformly pumping the blood out into the rest of the body. 204 00:19:30,390 --> 00:19:35,700 So where this will be useful is if we see a chunk without signal. 205 00:19:35,910 --> 00:19:43,590 So if we see something like that, then we know that that part of the heart has has potentially lost its blood supply. 206 00:19:43,830 --> 00:19:51,100 And so what we can do is we can try and restore that blood supply or we can decide if it's worth restoring the blood supply. 207 00:19:51,120 --> 00:19:56,310 So we can we can tell very early on with this technique whether or not the tissue will recover. 208 00:19:56,550 --> 00:20:02,610 And so that will help our cardiologists decide what to do with the patient to give them the best care that they can. 209 00:20:03,840 --> 00:20:10,140 And so that brings us to the end. So that was just a very new technique of looking at the heart. 210 00:20:10,680 --> 00:20:15,150 So if you have any questions, we'd like to answer them.