My name is Isabel Oliva Cortopassi. I am a associate professor and the chief of thoracic imaging here at Yale in the Department of Radiology. And I'm going to be talking about cardiac radiology as an introductory lecture. This is part of the Yale team based learning Session. The objectives are we're going to overview available imaging modalities to evaluate the heart. We will review their strengths and weakness and how it helps us decide which modality to use. We're going to see the indications commonly done for each of the modalities and go over some basic anatomy. The available imaging modalities include playing radiography, echocardiography, computer tomography, or CT or CAT scan, myocardial perfusion testing, which is a nuclear test. Magnetic resonance imaging, or MRI, and direct cardiac catheterization. Plain radiography is usually the first order imaging tests for patients who present with concern for inter thoracic disease. Even before you know it's cardiac related or lung if the patient has shortness of breath chest pain, this usually the initial modality is a chest X ray, and the reason for that is just X ray is readily available. You can be done quickly. It can be done at the bad side. It's not expensive. Even though exposes the patient to radiation is very low. Radiation is the lowest of all modalities. The patient does not need to receive intravenous contrast. But the problem is the images provided on a radiography have very low an atomic detail, because you have a 3D person projected into a 2D picture, so you have super imposition of data. Several structures can come in front of the other, and that may obscure pathology. Or it may make shadows, then look like pathology. That is not real. Therefore, this modality is neither specific nor sensitive. But it's a very good screening. When you look for life threatening pathologies, you want to make sure the patient doesn't have a huge pneumothorax or a wide out lung, so, it's a very good initial best. This is a chest radiograph. This patient has an atrial septal defect. We can see the borders of the heart, but you cannot actually see each chamber. We know the right heart border is formed by the right atrium. You actually see a little of the left atrium here, because it's enlarged. On the left side, you have the left ventricle and the left atrial appendage. You can also see in this case that the **** vasculature is engorged. The vessels are bigger than normally, because the patient has an ASD, or intercepted defect that is causing shunt vascularity. Blood that should be going to his extremities, to his body are going through the interracial septum back to the right side. Harmonic circulation and back to the lungs, so you have almost double amount of blood through the lungs. That's why you get engorged vessels. Another commonly used modality is echocardiography. It's also available and affordable. It doesn't expose the patient to radiation nor intravenous contrast, and usually after the chest. X ray is the next modality that is ordered for patients. When the intra thoracic pathology is suspected to be related to the heart, it can give you good anatomy and also some physiology. You can look at the valves opening and closing. You can look at the pericardium at each of the cardiac chambers. It's very operator dependent, so you need a good technologies to make sure you acquire the correct planes and images, and it's also dependent on patient's body habit. This, if the patient has a lot of so the continuous fat and clearly or big chest, you may not be able to reach the heart with the ultrasound. This is a picture of the echocardiography. You can see that this is the anterior chest wall. You have your probe there and you can see the right ventricle, the directors involved in the right atrium and on the left side you have the left ventricle. They might evolve the left atrium, so you can take a look at each chambers. You can see the valves opening and closing you, so you can look for regurgitation or insufficient or stenosis. You can also see the inter atrial septum in the intervening regular sector. And if the patient has a defect, you will be able to perceive that and look at the shunt of blood between the two chambers. Computer tomography. It's another modality. It's the CAT scan. It has excellent and atomic details. You could also have some physiologic information, but the cost of that is that you need to increase the radiation. So, the downside of computed tomography is the radiation exposure, which is much higher than the chest radiograph. It's also more expensive than just radiography. The radiation exposure used to be 20 times more or even 30 times more than a chest X ray. But these days, with the evolution of the technology, we're able to do a hard CT with about 10 times the exposure of our chest radiography, which is very good. But that doesn't give you a lot of physiology. And just to have an idea. If you were to do, physiologic assessment with CT, you need to expose the heart radiation throughout the heart cycle. So while the heart's beating you imaging and that gives you more radiation, which means about five times more. Every time you're making a decision in which test you use, you have to take in consideration the patient's age, because the younger the patient, the less radiation you want to expose them to. The contrast given in patients with undergoing computer demography is the eye ordinated contrast, and those are nephrotoxic. So, if the patient has renal disease or diabetes with potential microvascular kidney disease, you may want to consider a different test. It's used to look at the coronary arteries, the anatomy and also the presence of blacks. But you can also see other things, such as, in this case, you have the sternum and clearly the spine posteriorly. The decency order right ventricle, right atrium, left atrium, left ventricle in the left ventricular apex we have classification. Is this bright wall and in the lumen, which should be all bright with contrast, you have this feeling defect, which is a thrombus. This patient had a prior infarct in the LED territory and with cloth information on aneurism. Another test we use to evaluate cardiac disease is a nuclear stress test or myocardial perfusion. It's not very good to look at anatomy, so it doesn't give you a lot of an atomic details. But it's very good at physiology, particularly blood flow physiology. It's not as available as a CT or X ray, or an echo, so usually it doesn't get done in the same day. It has to be next day, so the patients have to be stable enough for that. They are more expensive, and also usually we want the patient to do an exercise. So, if the patient cannot exercise physically, we can also do a pharmacologic stress. But it's not as sensitive. This also exposes the patient to radiation. It's a different kind of radiation than the city, but nonetheless it is radiation. But the patients usually do not get intravenous contrast. And we're looking here is we image the heart. We inject a radio tracer, their goals, whatever the blood flow is going. So, you're myocardial, this is the left ventricle wall. You don't see the lumen, you don't see anything else. Wherever there is blood flow, the treasure of this bright spots go and light up the myocardial. When the patient is resting, there's blood flow throughout the myocardial. What happens when the patient has disease in the coronary artery is opponents stress the diseased artery cannot keep up with the flow. So, you get a profusion, defect or lack of brightness on the territory that is involved. So, in this case, is the interior Apolo, the LED territory. So, when you compare the rest and stress images, you can see there is a reversible defect in the LED territory. That means the patient has enough disease, two cows, angina. It needs to be reversible arised. Magnetic resonance imaging, our MRI gives you both anatomy and physiology is also not readily available as the first three tests. Although it may be more available than nuclear depending on the institution is very expensive as well, and it's a long test that requires patient corporation. The patient usually sits in the scanner for about 40 minutes to an hour, depending on the pathology being evaluated. It needs to do several breath holds. There is no radiation exposure. The patient does receive entrepreneurs contrast, but it's a different type than the CT1. What is a gadolinium based, which is not nephrotoxic, but cannot be given to patients with renal failure, because it accumulates in the body and causes the for nephrogenic systemic fibrosis. Magnetic resonance is the best modality to look at tissue characterization. So, if that's what you're looking for, you want to do an MRI, especially looking for tissue edema or a scare. You can also see the anatomy, so you can see the left ventricle, the mitral valve left atrium aortic valve in the aorta. All the four chambers, the septum just like an echocardiogram, and you can assess the same things. They're assessed by echo. You can look at the ventricular functions, you can look at the valves for insufficient estonuses. You can look at the size of the chambers, and in addition to all that, you can also look at tissue characterization. Myocardium should be dark on this delayed enhancement images. Every time you see bright, that means scar. The myocardial refuge in happens through epic cardio arteries that dive into the myocardial. So, the blood flow always goes from in to out. If you have a blockage at the endocardium is always involved. So, this is only some endocardium scar with a lot of preserved, via myocardium. This is another case with transmitter scar. The whole world is that there is infarct is infected, so in this case, it's not worth it to do a revascularization. The myocardium, is dead. In this case, you can still save all this myocardium if you open the blood flow back, that leads us to cardiac catheterization, which is an invasive test. It gives you the anatomy of the coronary arteries and some physiology because you can see the left ventricle contracting. And you also can look for fraction flow within a coronary, but it's mostly an anatomy test. The main advantage of this test is you can do treatment. You can put a stand on a corner that is diseased. It's also not readily available. The patient needs to go to the OR with anesthesia is the most expensive of all. It does expose the patient to radiation, and the patient also receives I ordinated intravenous contrast. But you can see you're a patient who had severe stenosis of the proximal LED coronary artery, and they stated it and it's wide open. Now you can see the contrast flowing. That's what cardiac catheterization does. So, these are the modalities available to evaluate the heart and heart disease. And should be always chosen based on the clinical concern, the availability, the patient age, thinking about radiation exposure, and what actually you were expecting from the modality. If you really want to know about scar or edema, you have to do a cardiac MRI. If the patient is having heart attack and it's revascularization, you go to the CAT. If the patient is a low risk patient and you don't think they have coronary disease, you can do a CT that is non invasive and rule out plaques in the coronary. The chest X ray is usually the first modality order. When a patient comes with justices in general, an echocardiogram is usually the first cardiac dedicated modality done before they all their tests. Thank you.
