So my name is Mike Stagner, so I'm a cardiovascular radiologist. So I read vascular CT and MRI. So we do all the blood vessels basically from the neck down to the tips of the toes, including arteries and veins. I also do cardiac CT and cardiac MRI. And being fortunate that I get to work at this nice, beautiful glass building, we have a combined reading room. So the nuclear cardiology reading room, the cardiac MRI reading room, the cardiac CT reading room, and the vascular CT and MRI reading room is the same room. So whenever we need an overread, they just look across the room and ask us for a read. So that's how we do it. And I'll show you a little bit live of how we actually go through those overreads. So if we look at the prevalence of significant extracardiac findings, it's a wide reported range, so from 4% to 38%. But there's been many groups that have shown that it's very important to look for incidental findings. So I think if you're scanning the patient, the patient has felt that radiation, I think we have an obligation to do the best we can for the patient with the images that we have. So as far as the approach to reviewing structures, it's very important to do it systematically. So the exact same way you would approach reading an echo, or the exact same way you would approach reading a nuclear cardiology scan, I would want you to approach it the same way overreading the CT scan. And this is the order that I use, and it's not important that you use my order, but it's important that you do it the exact same way every time, so that you don't forget any particular structure, especially when you find something that you don't have satisfaction of search. Okay, so first we start with the airway mediastinum. So I sort of start in the center, and then work my way out. And then we go into the abdomen and the chest wall, and I'll show you in a live case on how we actually do this. It's important to have proper algorithms for the mediastinum and the soft tissue structures. So it should be smooth, and this is an example of a smooth algorithm for soft tissue and mediastinal structures. And you want more of a sharper algorithm for the lung detail and the bone detail. It's also appropriate to use the right window width and window level settings for the anatomy of interest. So we have to use a more narrow range to look at the fat and the soft tissue, and a much wider range to look at the lung. These are the structures we're going to cover. Okay, so let me switch gears here. So I'm remoted into our PACS, and I have the protected health information hidden, so we don't have to worry about that. So this is what our studies look like. So first we'll start with a PYP study, because it has a larger scan range, just to show you the normal structures. It's important to know all the images that you have in your data set, so you know what to load. So here we have soft tissue, and we have bone algorithm, and we have the localizer. So it's important to make sure you look at the localizer. So we'll load this up first. So for the localizer, why do we look at the localizer? Well, the localizer is going to cover parts of the patient's anatomy that you will not cover with your scan. So if you did a nuclear cardiology scan, your coverage is only going to cover the heart. It's not going to cover this vertebral body. It's not going to cover this rib. So if you had a huge lytic lesion in this rib, or you had a massive lung cancer here, you would not see that on the CT images. But it's on the localizer images, therefore we'll libel for it. So we need to make sure we look at the localizer images. We have a sharper algorithm. We have a smoother algorithm. The smoother algorithm is going to be better for soft tissues. The sharper algorithm is going to be better for lungs and airways. Okay. So first we start centrally. So I start in the airway. So here's the trachea. And what we're looking for is we're looking for filling defects in the trachea. And if you have a patient that has a, if you have an innovated patient, you want to make sure the patient doesn't have a main stem bronchus innovation on this CT scan. So as we scroll down, we're looking for filling defects. We're looking for bronchiectasis, which is dilated bronchi. So I go down on one side, then I sort of come up on the other side. So that's our airway. Next from the airway is the mediastinal structure. So now I'm going to switch to my soft tissue algorithm. I'm going to use a soft tissue window, which doesn't allow me to see the lungs. It doesn't allow me to see bone cortical detail, but it does allow me to separate soft tissue from fat. And that's what we need to be able to do in order to look at the mediastinal structures. So if we, as we coming down, the brightest structure on a non-contrast, brightest soft tissue structure on a non-contrast scan is the thyroid gland because thyroid hormone is composed of iodine. So the iodine in the thyroid gland makes the thyroid gland brighter. It's important to look for thyroid masses. As we come down, you want to make sure you can identify your vascular structure. So we have the brachiocephalic vein coming over on the left is the brachiocephalic vein on the right. There's a catheter in it as it joins. Now this becomes our SVC. Here's our azagus vein coming in and the SVC is going to go into the right atrium. We see the arch vessels here. So we have the anominates, common carotid, the left subclavian. You can see aneurysms here. You can see heavy calcification. We have our aortic arch. We can see aortic aneurysms. We can see arch calcification. You can see a dilated pulmonary artery here. So just gestalt, the pulmonary artery shouldn't be bigger than the aorta. If the pulmonary artery is bigger than 30, then that's consistent with pulmonary hypertension. So we see our pulmonary arteries coming down. Now we see our heart. I think we know how to look at the heart. We see our pericardium here. So we want to make sure that there's no pericardial effusion. Here's our IBC. Here's the coronary sinus coming in right here. So that covers it for the heart. So for other structures in the mediastinum, we have this other thing that has air in it. So posterior to the trachea, we have the esophagus. So coming down here is the esophagus. Here in between the adzicus vein and the aorta is the esophagus here. Here we see it coming down. So we want to look here for hiatal hernias. We see no hiatal hernia there. So now as we're done with the mediastinum, we're in the upper abdomen, we're in soft tissue kernel, we're in the right window level. Let's just look at the abdomen since we're here. So how far down do we go in this case? Well, we go down to include both kidneys. So we see the left kidney here, the right kidney. At the top, we have the liver on the right. We have the stomach. We have the spleen here on the left. Here's the gallbladder. Here's the transverse colon sort of sneaking in, the hepatic flexure there. As we come down, we see the adrenal glands. So it looks like a Mercedes-Benz or a sort of a peace sign there. We have the pancreas, which sits behind the stomach. We have the splenic vein. Here's the uncentered process of the pancreas. So we do solid organs first, adrenal glands, then we go into the kidney. So here we see we have a lower density structure. So here's a renal cyst, simple renal cyst, and I'll talk more about pathologic findings as after this part. Here's the cranchoma of the kidney. We're looking for focal outpouchings, which could be a cyst or a mass. We're also looking for calcifications in the kidney for undocumented nephrolithiasis like this patient has here. My mother actually diagnosed herself with hypercalcemia because somebody missed this on her calcium score CT, and she picked it up on her own, good for her. So here we have the aorta. Now let's go back and look at the lungs. So we're done with soft tissue. We're done with abdomen. For bones, we want to go back to our sharper kernel, and we want to use a more appropriate window level for the bones, which is very wide, which allows us to separate the cortical bone from the medullary bone. Now the most important thing with bones is we don't want to miss a fracture, okay? So if your software can give you NPR, and I know most of the nuclear software can do that, you always want to look at your spine sagittal to look for compression fractures. You also want to do that if you have a lateral topogram, you want to look at that, and I'll show an example of that when we get to the cases. So I go straight to sagittal to look for compression fractures because we don't want to miss a compression fracture, okay? We can also have lytic and blastic lesions in the ribs. We can have osteophytes, which look really bad. They look much worse than they actually are, okay? And then lastly, we have to go back to the chest wall. So let me go back to our smoother kernel for the chest wall. So for the chest wall, we want to identify the breast tissue. This is a man, but men can also have breast cancer, and we call unilateral gynecomastia if we see it because that can be a precursor for breast cancer in men. So you're looking for asymmetry of the breast tissue is what we're looking for, and we're looking for nodes in the axilla. So that was a PYP case. Let me pull up a typical post-CABG case where we have stress and rest images, and I'll show you what we do for the lungs on that. This is the majority of the cases that we have. So here's the stress acquisition. So we have to find the correct images. So here we have our scout and our stress, and then we have our rest scout and the rest attenuation correction images. Now this could be on different days, and even if it's the same day, the patient's going to get off the table and get back on the table. So the localization is not perfect. It's not the same between the two days. Okay. So we load those up. All right. So we have the stress on one side, we have the rest on the other side. With our new software, we can link them and have them automatically registered by Hounsfield units, which is great, but the point of this is to show you how there's different levels of the scan. So on the stress part, we scan higher. So we have to make sure we look at the lungs on this part versus the other one, because this one doesn't go as high as this one. Conversely, when we look at the abdomen, the rest abdomen goes lower than the stress abdomen. So here I can see there is a little renal cyst on this side, which is not available if I only looked at the stress images. So it's important to look at both. Okay. Now also, here's the localizer again. So here's the SAGIL to look for that compression fracture. The localizer can also help you understand what's going on with pacemaker leads and AICDs and whatnot, or sort of orphaned epicardial pacing wires. They like to leave those in. Okay. So let's do our review of the lungs. So we do MPR, and I absolutely believe in MIPS. So I'm the one that converted our thoracic division to using MIPS. There was a great paper by Coach Gruden's brother, this radiologist with the same last name Gruden at UCSF compared radiology residents that had MIPS to chest attendings that didn't have MIPS to look for pulmonary nodules, and they were equivalent. So MIPS makes you as good as a chest attendant. And here's an example. So here with MIPS, we can see the small pulmonary nodules. It's important when you use MIPS to use a thin sliding slab, not a thick sliding slab. So here I'm using the wheel and it's making big jumps. Here I'm only seeing the potential nodular opacity on one slice, but I want to see it on multiple slices. That's what the MIPS does for us. So absolutely use MIPS on every case. I use MIPS in sort of this window is more for bones. You can quickly tell if it's calcified or not. So here I can see that's a calcified granuloma because I'm in bone window and it's bright. So that's how we do our lung review in the MIPS. We're going to go through a bunch of cases here. I tried to cover everything or things that you would see most commonly. There's going to be things not on this list and the idea of this is not to make you into a radiologist, but it's to try to give you an idea of when to ask for help. The best advice was to remember that these are very low dose, free breathing scans. The quality is not diagnostic most of the time, and the right answer is to recommend a diagnostic quality CT scan. So let's start with the airway. Here we see a filling defect here in the trachea. So we have a tracheal mass. So most tracheal tumors are malignant, so it's not a common thing that we see benign lesions in. So here we see a adenoid cystic tumor, can have squamous cell tumors. Any mass in the trachea should be evaluated with bronchoscopy. Now if you see a little bit of saliva, you can see little air bubbles that's layering posteriorly. I don't think you need bronchoscopy for that. That's just a little bit of mucus. But if you see something that is defying gravity like this, then we need direct visualization on that. Another example of an airway problem that we see here, we see these dilated airways here in the right middle lobe and also in the lingula, but we also see them in the lower lobe here. So this is bronchiectasis. This happens after infections. Usually the patients come with this diagnosis. We're not making this diagnosis. When we see in this distribution that's associated with mycobacterium avium intracellulare, which may have a different name by now. Cystic fibrosis, where they have cystic spaces, very large capacious bronchiectasis. This is more tubular bronchiectasis that we can see more commonly where we don't see very large spaces where this is just bigger than the adjacent blood vessel. We call that tubular bronchiectasis. These are the different types, cylindrical, varicose, and then cystic. Let's go to the mediastinum. So in the mediastinum, remember we talked about the bright organ being the thyroid gland. So here we see that the thyroid gland has multiple hypodense lesions in it. So there's no specific CT feature that reliably distinguishes it from a benign or malignant lesion. CT underestimates the number of thyroids relative to sonography. Most of them are benign. I'm not a thyroid doctor. So I always look this up whenever I see an incidental thyroid nodule. I don't keep this in my short-term memory and I don't think you should either, but you should know when to look something up or to ask for help. So we go to this white paper and I have three white papers. There's one for abdominal incidental findings. There's one for incidental pelvic findings, and there's this one on thyroid nodules. I'm happy to share those PDFs with the group after if anybody wants those, but I refer straight to these for these flowcharts for what to do for incidental adnexal lesions or incidental adrenal lesions. So if we look for suspicious, so what you're looking for, is there a suspicious feature? Well, what is a suspicious feature? That's something that's greater than 1.5 centimeters as far as a lymph node goes. If you have invasion of the adjacent local tissues, that's considered a suspicious feature. So if it's not suspicious, then we're based on size. So if the size is greater than a centimeter and you're young, they go to thyroid ultrasound. If the size is greater than a centimeter and you're old, you go to thyroid ultrasound. So it's 1.5 centimeters if you're over 35. So okay, next in the mediastinum, we see multiple lymph nodes in different nodal stations. So we see here paratracheal nodes. We see the prevascular node here. We see bilateral hyaluronidinopathy. We see the precarinal node here. So bilateral lymph node enlargement, that should always trigger lymphoma is the most important thing to not miss when you see bilateral lymph node enlargement. Of course, we can see that with infectious diseases. Typically if you have a pneumonia, it should be unilateral. It shouldn't be bilateral. Sarcoid is something that likes to give nodes in all these stations. So it could certainly be sarcoid or any pneumoconiosis can do this. You'd like to see calcifications in it though if it's a prior granulomas disease. If we have lymph nodes that are greater than 1.5 centimeters in short axis in the mediastinum, that's what triggers further follow-up or PET for evaluation of those nodes. Here's an example of a calcified node. So we have calcified hyaluronidin and mediastinal nodes. So that can indicate prior granulomas disease. So treated lymphoma can also have this appearance, TB. So if you have a patient that's coming from overseas or in a developing country, TB is a more popular diagnosis. In this country, histoplasmosis is probably the most common, unless you're in the Southwest and it'd be coccidioidomycosis, of course sarcoid. Calcification can occur after chronic, but typically it takes time for things to calcify. So you don't see that acutely. Here's an example of a typical sarcoid patient. So we see hyaluronidin adenopathy and we see this subcarinal, both calcified, and we also see this fibrotic reaction here. So this is pulmonary sarcoidosis. We already talked about some of the pneumoconiosis. We have a fair amount of sarcoid at our center and we do dedicated sarcoid pet protocol, which I'm sure you guys are familiar with. The nuclear medicine people usually overread those because it's a whole body pet when they do the sarcoid, not just the cardiac pet. So our nuclear medicine colleagues provide the overreads from that instead of the cardiovascular radiologists. Okay. Here's an example of a mass. So we see something that has heterogeneous enhancement with maybe necrotic center. So this doesn't look like a typical lymph node, which would be homogeneous and sort of kidney being shaped. So this is an anterior mediastinal mass. For anterior mediastinal masses, we do have a differential that everybody learned in medical school, the terrible T's, which includes a terrible lymphoma. So we have thymic, thymoma, thyroid also in that list. Here's an example of when we have air that has entered the mediastinal space. This can happen spontaneously. This can happen from a chest tube, not being with a side port, not being in the wall. So this is an example of pneumo mediastinum and we have a ton of subcutaneous air here. This is usually a post-traumatic phenomenon. We do see air has made it actually into the epidural space here. This can happen in endoscopy procedures, bronchoscopy, and also upper GIs. This can happen when they're pumping air into the patient to dilate things. This patient, we see that there's actually enhancements of the pericardium. And I included both contrast enhanced studies and non-contrast enhanced studies because I'm sure some of the readers here also probably read cardiac CT, where you're going to see contrast enhancement. In the nuclear cardiology readers probably won't see as many contrast enhanced studies, but you can see enhancement of the pericardium. You don't need to do a cardiac MRI for that. You can see that with CT and actually you can see it better in CT in some cases. You can see the parietal and the visceral pericardium is enhancing here and we see a more hypodense fluid. So it's less dense than the enhancements. This is a moderate pericardial effusion. So if you can see a circumferential pericardial effusion, Lynn Lilly, who's at the Brigham, taught me that it has to be moderate by definition if it can make it all the way around the heart. So if we can get the attenuation, and this is basically in any fluid collection, if the attenuation is less than 15 hf units, that's consistent with water or transudated fluid. Over that you would be considering an exudated fluid or potentially a hematoma. If your hf units got to be 50 or a little bit higher. You can't really get over 70 hf units, maybe 80 with acute blood, but usually it should be in the 50 or 60 range. And then it comes down over time, over a day or two, that number will start to go down. Here's an example of a pericardial effusion and we have bilateral pleural effusions in this case. This pericardial effusion is high density. So just looking at the effusion, gestalt, you can't tell, so you have to measure here. So on a non-contrast, you can tell if it's the same as the adjacent muscle, you know that muscle is 40 hf units. If you can visually tell it's less than the muscle, well, maybe you can tell, but you have to have the right window level for that. So it's always better to just drop a hf unit marker. You want to make it about a centimeter or so. You don't want to make it a pinpoint size because when it's pinpoint, you may have noise, could falsely elevate that. So you want to give it a decent sample size to get a more accurate number. So if this number is higher, then we're worried about blood in this space. Still waiting for my chylopericardium. I'm still waiting. Don't have one yet, but if I have one, I'll add it to the doc. Okay. Here's another example of a mediastinal lesion. We see this lesion here in the posterior mediastinum, so close to the esophagus. It's close to the IBC here. So this is a foregut duplication cyst, also known as a so-called bronchogenic cyst. This is in the typical location, but this should be a lower density structure between the thoracic spine and the IBC. This is a very common location. It's important to make sure that this is not a solid mass. If this is a solid mass, then the patient would need to go for a proper CT evaluation and possibly a PET CT to look to see if this is a malignant tumor or not. It's important to differentiate a mass from a hiatal hernia, and that's just going to take practice looking at the stomach and watching it curve in through the hiatus into the esophagus. Here's another case. When we look at the posterior mediastinum, we see the esophagus, but it doesn't look entirely symmetric. You see some asymmetric thickening on one side of the esophagus here. So focal asymmetric thickening of the lower esophagus. This is not really a mimicker of a hiatal hernia. So a hiatal hernia shouldn't have asymmetric wall thickening. The wall should be thin. Sometimes it's hard to tell if the wall is thin if it's collapsed, and I know that that's a challenge. If you have asymmetric thickening, the patient needs to go for direct visualization with endoscopy or an upper GI series, or potentially just an esophogram alone, just depending on practice patterns and your location. So we see the stomach, that it looks like it's in the chest, but we also see the esophagus. So if we can see the stomach and the esophagus on the same level, we have to worry about a paraesophageal hernia. So with a paraesophageal hernia, the stomach actually herniates through a separate hole, which is different than the aortic hiatus. So normally the esophagus and the aorta go through, this is called the aortic hiatus. There's a separate hole that the stomach pops through. And because this is a separate hole, it's typically a smaller hole, then it's at further risk from being tethered and then can torse. And gastric torsion is a very serious complication. Here's another view of the distal esophagus. So here's the esophagus, and they helped us by putting an NG tube in it. So now I can know that that's exactly where the esophagus is, no question. Contrast is on board. We see the aorta is bright. We see that we can see some of the spleen coming in. There is ascites here. This is the liver. And if we look at the liver, it doesn't have the normal smooth appearance that we normally think a liver should have. So this would be a nodular liver. When we have nodular liver, we have ascites where we have to think about cirrhosis and portal hypertension. And then we have this bag of worms around the esophagus. So this is massive esophageal varices here. Another thing that's in the differential is Castleman's disease, which is a disease of the lymph node where they enhance very, very brightly, almost like theochromocytoma would enhance that rapid enhancement in that bright. Also potentially an IVC obstruction with collaterals can look like this. But typically the only way to get esophageal varices is from portal hypertension, most likely. Okay, let's go to another case. So we're still in the posterior world here. So we're going further back and we see adjacent to the spine, we see there's something extra that shouldn't be here. So we should just have the pleura here, but we see the extra, there's a mass. Actually, there's masses on both sides. So here we have posterior mediastinal mass. And if we look at the location of the mass, if we go either superior or inferior, we'll see the neural foramina comes out here. So that's a good place to have a neurogenic tumor. So patients with NF2 can have tumors here or just old fashioned schwannomas can end up here. You can also have lymphadenopathy in this location, but this is not entirely characteristic of lymphadenopathy. It'd be rare for it to be in that location. Also extramedullary hematopoiesis. So patients post splenectomy can have intrathoracic extramedullary hematopoiesis that can mimic posterior mediastinal mass. Let's move on to the lungs. So here we're at the top of the lung. So when we're looking at the lungs here, we see this extra line that we don't normally expect at the lung apex. So this is called the azagus fissure. It's an accessory extra fissure that most of the population doesn't have. So this is a normal variant. Here is a little bit different. So if we look at these lungs, normally the fissure location should be symmetric. So here we see the fissure on the left. If we look for the fissure on the right, well, it's not there. It's pushed up here. So the way to move a fissure is you either have to expand the lung from one side or collapse the lung from the other side. So what happened in this case is we have an occluded bronchus and we have collapse of the right middle lobe. So with the right middle lobe atelectasis here, we have collapse and the worry is that we have a bronchogenic tumor that's causing obstruction there. Any new cases of right middle lobe collapse should be evaluated with bronchoscopy. So what about this case? So let's take a look. And what's the finding here? This one is a little bit more subtle. So if we look at the periphery of the lung, we see it looks like there's some extra sort of spaces there and also along the fissures. It looks like emphysema, but it's only seems to be along the fissures. We don't see big holes in the middle of the lung. So this is what's called paraceptal emphysema. This is also a smoking related disease. And the relevance of this is that it tells you that the patient is high risk for lung cancer. For when you have to recommend followup for the pulmonary nodule that you saw, you know that this patient is in the high risk pool. When we get to the Feissner Society criteria, we separate our recommendations based on high risk and low risk patient populations. And we'll talk specifically about what those are when we get to that slide. Okay, here's an example of emphysema, but it's predominantly at the lung bases. So this is not at the apex, and this is worse at the lung base. So this is one of the things we learned in medical school that you rarely get to see in real life. This is alpha one antitrypsin deficiency, basilar predominant pattern. And these are younger patients, and these are non-smokers also. This is not a smoking related disease. So this patient wouldn't be at higher risk for lung cancer. These patients typically don't live old enough to get lung cancer from smoking. So next, let's move on to more diseases of the lung. So here we see a focal area of consolidation. And the word consolidation means the loss of pulmonary parenchymal markings sufficient to obscure the vasculature. And that definition was originally used for chest X-rays, but we apply it to CTs. So if you cannot separate the blood vessels, so here we can separate the blood vessels from the lung. If we lose that ability, that is the definition of consolidation. You can also have air bronchograms, which we have in this case. And this is a patient with pneumonia. Atelectasis will be a decompressed lung, so you won't have air bronchograms. And also there's volume loss with atelectasis. So it's fairly easy to tell the difference between atelectasis and pneumonia. Now you can have combined situations where you have the patient has pneumonia, they're hospitalized, so they have dependent atelectasis, but they also have pneumonia on top of that. And how do we sort that out? Well, if you have contrast on board, you can. You can separate the enhancing lung, which is normal, from the boggy, pus-filled lung, which is not enhancing as much. We don't really have that luxury on a non-contrast study. The two mimickers, the two cancerous mimickers of pneumonia are primary pulmonary lymphoma, can look just like a pneumonia, but the patient didn't have a febrile illness or a cough. They just have this consolidation that doesn't get better, that doesn't go away. Same thing with a bronchoalveolar cell carcinoma can also have that. Let's take a look at this lung. So here, these two lungs look like they're not even from the same patient. Well, guess what? This patient's had a lung transplant. So here you can see the anastomosis here in the bronchus. If you look at this lung, this is an example of honeycombing. So this is a patient with pulmonary fibrosis, status post unilateral lung transplant. So we have the normal lung here and the fibrotic lung here. So what causes the honeycombing is the loss of the alveolar spaces and the overall destruction of the alveolus and the internal components of the lung itself. That pulls the lung apart, which can have bronchiectasis. So it keeps the bronchi open all the time. So they have problems with air trapping in the bronchi. You also have volume loss. Typically, pulmonary fibrosis is lower lung zone predominant. Can be idiopathic. CT is not making the diagnosis of pulmonary fibrosis. The pulmonologists have made this diagnosis years ago. So by the time where we see this stage of disease, the patient has long been diagnosed and been treated. Okay, here's another primary lung finding. So it looks like we have a solitary pulmonary nodule here in the right lung apex. This patient does have emphysema. So when considering what follow-up strategy, this puts the patient in the high-risk category. So this is an indeterminate solitary pulmonary nodule. If we actually, if we look a little bit closer, there may be some calcification in there and maybe some fat. So this could potentially be a hematoma. The Fleissner Society initially developed criteria to deal with solitary pulmonary nodules that were incidentally found on a chest CT. Then people started applying that to every pulmonary nodule that they saw. We realized that it didn't fit for all of the pulmonary nodules, and we've had several rounds of the Fleissner Society criteria. I think this is the fourth round, maybe it's the third round. And this is the actual text that we put in the report whenever we see a single solid pulmonary nodule. And if the patient's in low-risk, I only include the low-risk part of the text. And if the nodule is less than six millimeters, I delete this part. So I don't put it, I only put in the text that's relevant for that patient's pulmonary nodule and not to just flood the report with a bunch of extra junk that somebody's gonna have to read and then dismiss. Okay, so notice how these are gonna change a little bit when we go from single solid to a multiple solid. So this number nine changes and these numbers change. Again, guys, I'm a radiologist and I'm not keeping this in my short-term memory. These are macros that we keep in our PowerScribe system that we plug in depending on how big the nodule is, depending on if the patient's high-risk. So if the patient's high-risk, we know they're high-risk because they're a heavy smoker. Either we can see that on the images or it's part of their LMR. Patients that have pulmonary fibrosis are at high-risk for lung cancer. They can't, their lymphatics don't work very well, so they can't clear insults into the lung. The other patient population that's increased high-risk for lung cancer are the asbestos exposure patients actually have a higher risk for regular lung cancers more so than mesothelioma. But all we think about is mesothelioma because of the litigious business of that particular disease. Okay, here's the single sub-solid nodules. So when we get into sub-solid and solid and all of this sort of stuff, part-solid, it's my opinion that the typical attenuation correction CTs that you guys are gonna be using cannot discern whether it's part-solid, ground glass or not. So if you see the nodule, you punt and you say, we need a diagnostic quality CT because you cannot sort out if it's ground glass or part-solid, okay? Also, you haven't imaged the entire chest. So you may have only seen the tip of the iceberg and if you see that one pulmonary nodule on your cardiac CT, the patient could have a bigger cancer at the apex that we didn't see. And here's the recommendation for multiple sub-solid. This thing, the intrapulmonary lymph node is also called periphysiol nodules. The entire radiology community did not know that we had intrapulmonary lymph nodes for years. And this is why we had to change the Fleischner criteria because we were calling all of these as potentially lung cancer. We dismiss these routinely every day. If it's on the fissure, if it's not round, if it's not crossing the fissure, if it's not speculated, it's gonna be an intrapulmonary lymph node. And this is an example of those. You see how this is on the fissure, it's triangular. This one's on the fissure, it's flat. So cancers are, you know, they start from a point cell and then they grow out in all directions unless there's something abutting it, keeping it growing from one direction that it could potentially grow through. So this is a good way to dismiss a lot of pulmonary nodules. And thanks to Roshna Madan, our chest radiologist at our site for giving me this slide. Okay, here's an example. This, we have another pulmonary nodule here. This one looks very similar to that other one we showed. We see fat attenuation in it and we see calcium attenuation in it. If you have those two things, it's diagnostic of a pulmonary hematoma, no further followup required. Here we see multifocal ground glass opacities and actually some with consolidation. This could be a COVID patient for sure. So this is a case from circa 2009, but if I showed you this image to a chest radiologist today, this is COVID-19 until proven otherwise. So you're not directly imaging the virus, but you're imaging something further down the pathway. We're imaging ARDS here is what we're seeing. I'd like to show you guys a couple cases of COVID. So let me load up this one, which is multifocal ground glass nodules. And that one looks more similar to what we just saw. So here we see multifocal ground glass nodules. As I scroll through, you'll see them pop in and out of view. So here's a good example. So multifocal ground glass nodules. Let's go to another one. So we go to multifocal ground glass opacities. This looks a little bit different. The opacity is basically a bigger volume than the nodule. So this whole space is considered an opacity. Here's another one. It almost looks like an artifact, like it's not even real, but it sure is. So that's your ground glass opacity. And then lastly, we have what it looks like, what most of the patients end up looking like, something sort of like this. We have a mixed appearance of multifocal consolidations, ground glass. Patients have bronchiectasis with this. Patients also have, and I've seen PE in these patients. I've seen patients would have pulmonary hypertension actually, because the pneumonia is so bad. We see the pulmonary artery dilates in some of these patients. So this is an example of some of the findings you can see with COVID. Whenever I'm overreading a nuclear medicine study and we have a couple of nodules and we don't have the whole chest, that's what we recommend. Diagnostic chest CT and send it to the experts. Let's talk about the pleura. So here we see, we see multifocal pleural plaques and you identify a pleural plaque by the contour of the pleura. So it should be nice and smooth when you're in lung windows, but we see these things sticking out here. And then also we see a focal area of consolidation in the lung, which has sort of a swirly appearance to it. This is what's called rounded adalectasis. And these are pleural plaques, multifocal pleural plaques from asbestos exposure. So what happens in asbestos exposure is the asbestos particle ends up sticking out of your visceral pleura. It rubs on the pleura over the ribs and you get these plaques from irritation. You can get mesothelioma from the asbestos particles also, but the plaques are not what turn into mesothelioma. You can also get pulmonary fibrosis from asbestos exposure. And that's called asbestosis, which is you have to have pulmonary fibrosis from that. But this is rounded adalectasis. So rounded adalectasis has a characteristic appearance and it was actually described in this patient population. They did PET CTs on all these patients and they kept coming back negative, negative, negative. And that's how we figured out that this was rounded adalectasis. Here's an example of mesothelioma. So we see the unilateral pleural plaque, nodular pleural thickening, this very thick rind filling the chest. Now there's other diseases that can look like this. Metastatic disease from breast cancer or lung cancer is much more common. We're a mesothelioma center, so we get to see a bunch of these very frequently, but it should be circumferential involvement, mediastinal pleural involvement, soft tissue nodules, pleural effusions. So this is a bad news when we see this. Let's go to the bones. So here's that sagittal view, the sagittal localizer on the PET. This is the PYP study I was showing you before. So we can see there's loss of height of this vertebral body. So this is gonna be, we count up from L5, four, three, two, one. So this is T12. Here's the corresponding CT image. We correspond on degree of loss of height. And if there's any spinal canal stenosis and whether or not we think it's acute or chronic, if it's chronic, you'll see this well-formed cortical margin around the fracture fragments. If it's acute, you won't see that. We don't wanna miss compression fractures, especially on patients in the hospital. I have heard of a litigious case of a patient fell in the hospital, got missed on a topogram, and it was a lawsuit that was a judgment that got lost. Here's another example of a bone finding. So we have multifocal sclerotic lesions in the bone. So multiple osteosclerotic lesions. And what happens is if you see this, the patient needs a bone scan, unless this is already known. So osteopoikalosis is a rare condition where you basically have a bunch of these that are benign. But most commonly, this was gonna be, you're thinking about prostate cancer meds in a patient like this. So if you see multiple sclerotic lesions, I would go to the prior study. If it's not there in the prior studies or if none are available and there's no history to explain it, then I would go for a bone scan. Here's another example of a benign osteos lesion. So here we see this focal excrescence of bone emanating from the end plates of the vertebral body. So the body tries to stabilize the joints. And it does that with these osteophytes when there's too much joint mobility. Sometimes that actually causes adalectosis in the adjacent lung. And that's expected. Here's something we do have to worry about. So here we see this section of the rib is missing. So it's good to use symmetry when looking at the ribs. So here's the appearance of this rib. So this is an expansile lytic lesion. So this is going to be met or a primary bone tumor. Let's go to the upper abdomen. So if we look at the abdomen, we see visually we can see a difference in attenuation between the liver and the spleen and between the liver and the muscle or the diaphragm. That's typically where I'll notice it or the liver and the hepatic veins. You can see the hepatic veins on a non-contrast study and they're brighter than the liver. Because you've dropped the attenuation of the normal parenchyma, but the veins have maintained the attenuation that's driven by the hematocrit actually. The higher the hematocrit is, the higher the attenuation in the order in all the blood vessels will be. But to diagnose fatty liver, absolute Hounsvig units less than 40 or greater than a 10 Hounsvig in difference between the spleen. And this is important because you could have a patient have a metabolic syndrome or NASH that's undiagnosed and you can really affect the treatment in the patient by making this diagnosis. Here's an example of a benign lesion of the liver. So we see well circumscribed lesions that are low in attenuation. We do wanna measure the Hounsvig units here. And here we're getting less than 15. So we know this is a simple cyst. Here's something that's low in attenuation, but is not low enough to be a simple cyst and also has peripheral nodular enhancement. We have two of these lesions in the liver. So this is an example of liver mets. So we have a necrotic center here. This is very characteristic, sort of a halo type of appearance with peripheral enhancement. You can have hypervascular liver lesions. Some of them can have a characteristic. So hemangiomas have a characteristic appearance that has this sort of chain of lakes appearance, but that's different than this. This is more homogeneous. So this could potentially be an HCC, it could be a mets or it could be an adenoma. Here's another liver finding that we can see. So we have air in the bile duct. So if you see that the most common diagnosis is the patient just has had an ERCP and that's a normal benign air. But if the patient's sick, that could be from cholangitis or from an enteric fistula. The patient is really sick. Here we see I think calcified gallstones. Other findings you would look for would be fluid around the gallbladder or a dilated common bile duct. Here's an example of what the normal spleen looks like post contrast. Sometime it actually looks like masses in the spleen as you can see like the red pulp and the white pulp, different areas. That's why we have this different sort of heterogeneous appearance. And you should just completely discount this appearance. In order to properly look at the spleen, you have to wait 70 seconds. You can't look at it in the early arterial phase. Here's an example of an abnormal spleen based on size. So any direction over 14 millimeters is consistent with splenomegaly. And that's an important diagnosis to not miss mainly because we don't want to miss lymphoma. Don't want to miss lymphoma. Okay, here's an example of granulomata. One of my favorite words to use. We have multiple granulomas throughout the spleen. And that's just prior granulomas disease. Let's keep going. So the adrenal gland. So here we see a focal area of thickening that we could probably drop a Hounsford unit measurement on and measure the size of. And we see the Hounsford units are less than 15 here. That's consistent with an adenoma. We don't have cysts in the adrenal gland. So we don't have to worry about confusing this with a cyst. Other things you can have in the adrenal, you could have an adenocarcinoma, which would enhance. You can have a lipid poor adenoma, which would not drop the Hounsford units less than 15. Then you would have to send the patient for an adrenal washout study or a dedicated MR to separate them on chemical shifts. Here we see just a nodular appearance of the adrenal gland where it's not really big enough to have a discrete measurement or drop a Hounsford unit. So that's just adrenal hyperplasia. We don't make too big of a deal out of that. But if patients have other potentially endocrine issues, that'd be a reason to report adrenal hyperplasia. If we go down to the kidney, we see dilatation of the renal pelvis. So we're effacing the renal pelvis fat here and it's full with fluid. So this is bilateral hydronephrosis. That's important because you can have proximal obstructing lesions or an obstructed bladder. Here we have a benign lesion of the kidney. So we have a bilateral actually. So we see cysts. I think a cyst is a cyst no matter where it is. So whether it's in the liver or whether it's in the spleen or it's in the cyst or it's in the kidney, it's still a simple cyst and doesn't require any followup. And lastly, two more cases, chest wall and breasts. So here, if we look at the breasts, the fellows love to find breast calcifications on the nuclear cardiology service. The great thing about calcifications that you can see on a CT is that they are macro calcifications. So what we learned about breast cancer is that the diagnosis is made in mammography by looking for micro calcifications, which demands the highest possible spatial resolution that's available with our technology. The matrix size of these images are 32 by 2800. And you still have to use a magnifying glass to see it. So by definition, this has to be benign calcification. Also, we want to look for asymmetric breast tissue density. One of the issues with that in CT is the breasts are not forced into a locked position like they would be in a mammogram. And the breasts can be mobile and the breast tissue may look different because the level of the breast is not necessarily the same. So you may need to have to scroll up or down different slices to match up the asymmetry of the fibroblangular tissue. And this is what we're looking for is we're looking for asymmetric tissue in one side. And here we can actually see there's traction. There's a reaction here. And this is a breast cancer. But thanks for your attention.

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