Good afternoon, on behalf of the RS&A Educational Committee and our track chair, Dr. Diane Strollo, we welcome you to the Essentials of Emergency Radiology Imaging course, MSES P1. My name is Matthew Heller. I'm the moderator and first presenter of today's session. We have a great lineup of speakers, as you can see listed here. My topic is CT upon abdominal trauma. I have no relevant disclosure. Our objectives are to briefly review technique and then to list and review the key imaging findings upon abdominal trauma. For an overview, I'd like to start with a mention of the technique. We should remember the prefix multi, meaning multi-phasic imaging, to include arterial and venous phase imaging of the upper abdomen, multi-planar performance, and multiple milliliters of contrast material to get a good contrast bullets for best organ evaluation. The injury types can be roughly categorized into these four categories, and the most important is the vascular injury, as it is most life-threatening. Finally, management consists of discussion with our surgical colleagues. It's important to be familiar with the American Association for the Surgery of Trauma, Luteal Injury Scale. I encourage you to read this article referenced at the bottom of the slide, or create a summary of the optimization for trauma imaging. There are organ injury scales for all organs, and it's impossible to memorize the components of each, but it's nice to be able to refer to them and to use the proper terminology when discussing with our surgical colleagues, so I reference this slide here for you to use in the future. This article came out in 2018 and discusses the updates to the spleen, liver, and kidney that happen as the organ injury scales are evaluated and revised over time. In this edition, vascular injuries were added as components of the rating, and this is important as we know that there is increased failure after non-operative management of vascular injuries. Let's take a second to review the two major types of injury for abdominal trauma, pseudoaneurysm, and active bleeding or active extravasation. Remember that the arterial phase makes the order very bright, homogeneously enhanced. Similarly, the pseudoaneurysm follows this pattern, and also on the venous phase as both tend to wash out or lose some intensity. Pseudoaneurysm is typically well marginated and ovoid route, or if irregular, has a wall that can be traced. During arterial or active bleeding, there is a similar following of the blood pool, so it follows the aorta, and there is irregularity, however, of the confines of this active site of bleeding, and over time it gets bigger, it changes shape, and becomes more dense compared to the aorta, which washes out during the venous phase. This can be applied to any organ. When we look at the splenic organ injury scale, we notice that the grade 4 injury consists of a vascular injury confined to the splenic capsule, and a grade 5 injury is a splenic vascular injury that is extended beyond the capsule into the peritoneum. Here's an example of a patient underwent trauma from a motor vehicle accident. You'll notice that there is a little dot of contrast here in the sub-splenic space within the context of a large hematoma. During the arterial phase, on the venous phase, this becomes bigger, it changes shape, and becomes more dense with respect to the aorta, which is washing out during the venous phase. This is a grade 5 injury. Again, the summary and main points of this are to recognize that active bleeding changes shape and location, gets bigger, and becomes more dense relative to the aorta on the venous phase. Here's a patient with a high-grade splenic injury from a motor vehicle accident. You can see there is an extensive laceration hematoma within and around the spleen, and there is a pseudoaneurysm confined to the splenic parenchyma. Based on this image, this could be called a grade 4 injury. However, if we look more superiorly in the same patient, there is extra-splenic active bleeding, and so this is a grade 5 injury. Sometimes patients cannot or do not get contrast initially. We can apply the sentinel clot sign, which says that where the hematoma is most dense identifies the organ of injury. Notice that the hematoma is more dense around the spleen compared to the hematoma or hemoperitoneum around the liver, thus identifying the spleen as the organ that was injured. This patient didn't go on to get contrast material. You can see that the spleen has very irregular and extensive lacerations, and there's active bleeding within and around the spleen during the arterial phase. For the liver, vascular injuries were added as well, and if a vascular injury is confined to the liver, it's grade 3. If it extends beyond the liver, it's grade 4. So here's a patient that had a trauma. There's a hematoma and laceration in the posterior segment with two small hyperattenuating clot signs, which were pseudoaneurysms. As far as focal hyperattenuation goes, there is a differential. This could be pseudoaneurysm or active extravasation. In this case, it washed out and followed the aorta on the venous phase. Other considerations may be bone fragments or foreign bodies. Here's another patient with a vascular injury of the liver. You can see a very extensive hematoma, laceration, and area that is devascularized. There's also this irregular enhancement or extravasation within the liver, and then there's extra hepatic active bleeding as well, so this is a grade 4 injury according to the liver or scale. This is a patient who was transferred from an outside hospital, described as having a grade 2 injury because of the size and extent of the hematoma and laceration. Also within that is a rounded vascular enhancing structure that parallels the blood pool, and this was a pseudoaneurysm within the hematoma, so this was elevated to a grade 3 injury. This can also result in ductal injury, especially when they're deep like this, going from the subcapsular portion all the way to the level of the hylum, essentially. In these cases, it's very likely that a bile duct was traversed and there is a bile injury, so this fluid out here may be hematoma, it may be a bile that's leaking. These are patients that may benefit at the time from a hepatobiliary scan or MR within a hematobiliary agent as follow-up, or at least to get a follow-up CT. You can see in this case, the lacerations have healed, but there are two bilomas because of bile duct injury that was not recognized at the time. Here's a patient with another very deep laceration, it kind of goes off into the right lobe here, but another finding is involving the gallbladder. We should be aware that there are indirect signs of gallbladder injury, I like to think of them as external and internal, so external neural thickening and some pericholecystic fluid, and then internal if the lumen happens to be collapsed or there is blood within the lumen, that's a sign of gallbladder injury. It's rare that we see a case like this where there is actual mucosal discontinuity or a flap, clearly that is a gallbladder injury. Pairing the pancreas, it is a difficult organ to image on trauma because there is no capsule, so we have to rely on secondary findings such as peripancreatic fluid, especially fluid between the posterior aspect of the pancreas and the front wall of the sphenic vein. If there's fluid or blood there, that's a good sign that there is a pancreatic injury. If there's going to be a laceration, it's most likely to be in the body because with rapid deceleration, the spine acts as a fulcrum and puts pressure on that part of the pancreas. In this case, you can see a through and through injury here, this crosses the pancreatic duct. There's also a site of active bleeding here, which became bigger, changed shape and became more dense on the venous phase, consistent with active hemorrhage. Here's the surgical resection specimen showing that laceration right in the body. The pancreas can also be confusing in patients who are hypovolemic. This is a case of a patient that was thought to have a pancreatic injury, but when we look at this, there's really not a pancreatic defect. There is fluid around there, but we also noticed that there is a very unusual look of the bowel. It's very hypovolemic, almost looks like a caterpillar, the so-called caterpillar sign, and it's very thick. In this case, this is the so-called hypoperfusion complex. In patients that have had hypovolemia from trauma, notice that the IVC is relatively decompressed. There is edema of the pancreas and edema of the bowel. So this is hypoperfusion complex. Here's another case where the bowel looks very abnormal, same kind of appearance, it's very hypovolemic, and this is a physiologic response to trauma again, the IVC is collapsed due to hypovolemia. The good news is with treatment fluid resuscitation, this normalizes, this was just about a day and a half later, and the bowel has become completely normal, the wall thickening has gone away. So note, this is a physiologic response to hypovolemia, not actually bowel pancreatic injury. For bowel cases, it's nice when there is pneumoperitoneum, it helps us localize the injury perhaps, or at least detect that there's been a perforation. However, we do not need to have free air to have bowel perforation. In this case, there was a tear of the jejunum, and there was no free air, but there was fluid and blood around the wall. There was a little bit of wall thickening in this injured segment, and there was inter-loop fluid within the mesenteric bleeves, all findings that should raise your suspicion for a bowel injury if it's isolated like this, involving a segmented bowel. So in summary, it's important to be familiar with the injury types, to also be familiar with the American Association for the Surgery of Trauma, classification to facilitate communication with our colleagues in surgery, and to note some of the pitfalls we talked about today. Thank you very much. Let's take a look at a case. This is a patient in a high-speed motor vehicle accident who underwent a trauma to the spleen, and you can see here there is a vascular anomaly. This is a pseudoaneurysm, relatively well-marginated structure that follows the arterial blood pool during the venous, I'm sorry, during the arterial phase. So because it's confined to the spleen, this is a grade 4 injury. This is the venous phase in the same patient. Notice that the pseudoaneurysm is now nearly impossible to see it blends in because it is washed out, similar to the aorta, and this is the importance of doing a biophasic examination of the upper abdomen. You can also see a splenic laceration here in the posterior pole that goes from the front to the back. Hi, my name is Mark Mullins. I want to thank the organizers for inviting me to talk about imaging acute neurologic disease. I don't have any conflicts of interest for this talk. For the sake of time, this is going to move pretty quickly. What I suggest you do is, when I show images, pause and see what you think about the images, see what you would say about it, and then when I show you the word slides to describe it after that, again, pause and you can look through what's on the slides as well. I'm only going to talk about a couple of things on each slide. The way I organized this is according to the ACR appropriateness criteria, which you can see here. I'm only going to talk about adult presentations today, and you can see the list here. We'll go through each one of these. First patient, first case, altered mental status, right frontal lobe mass with central restricted diffusion, thin rim of enhancement, peripheral enhancement, so that's hypogenic brain abscess to a proven otherwise. Hemorrhage can restrict diffusion. There are many things that can restrict diffusion, but that particular appearance is a little bit different in general. You want to figure out what the source is, especially in a presentation like that. You're going to think about perinatal sinus disease. I mentioned all the infectious diagnoses present, including ventriculitis, meningitis, cerebritis, any of those that happen to be there as well. So moving on, different patient, different case. This patient has ataxia. You can see that they have an intraparenchal mass lesion with a prominent exophytic component. This is centered in the cervical medullary junction, no real enhancement to speak of, and so there is a differential diagnosis for this appearance, but brain stem glioma is at the top of the list, can result. Anything to posterior fossa can theoretically result in ataxia, and then whenever you see a mass, basically that's a positive volume situation, differential diagnosis, think about inflammatory diseases. There are some other things as well, but that's sort of like near the top of the list. Intraaxial versus extraaxial, exophytic versus not, enhancement versus not, there are a few special situations with this, and again, anything to posterior fossa can result in hydrocephalus especially non-communicating hydrocephalus. This patient with a perfusion scan for cerebrovascular disease, you can see elevated Tmax in the left MCA territory, distal to the stem, CBF decreased in the left MCA distribution, CBV relatively normalized, maybe a little bit, but close. So generally speaking, territory at risk for infarction, left MCA territory, and there are other things you think about, but of course, typically you go on from there, and does it fit the clinical presentation, do you know why, those kind of things from there. Don't forget about border zones in addition to the traditional territories, subacute infarction can be difficult to diagnose if it's the first presentation, can be swollen, that kind of stuff. If you ever see hemorrhage within the brain parenchyma and you don't know what it's from, one of the things to think about is hemorrhagic venous infarction, so make sure you check those neural sinuses. Patient with cranial neuropathy, basically you want to look from nucleus to end organ. In this case, this patient has a mass here, I didn't show you the T1 pre, but that's true enhancement, it follows the expected course of the right third cranial nerve, so that's a nerve C tumor, typically schwannoma. One of the things you always want to think about is could it be perinatal spread of malignancy. In terms of protocoling, brain plus orbits would typically be the approach for that particular presentation. Skull base could theoretically be optimized depending on which nerve we're talking about. Figure out whether the patient has a history of skin cancer, especially squamous cell carcinoma, and that raises the stakes in terms of perinatal spread of malignancy, but you want to think about it in everybody, so it's at least something to think about. Is there any denervation present that tells you you weren't more worried about that particular nerve, and then look at the adjacent skull base. Maybe they have metastasis, maybe they have myeloma, maybe they have something else that's pressing on those nerves, so think about that as well. Different patient, different case. This patient has a minimally displaced right frontal skull fracture, deep to that they have an extra axial radiographically acute hematoma, acuity by hyperdensity here, they have probably contusion, maybe some subarachnoid hemorrhage back here. This is an extra axial hematoma, crosses the midline, it's adjacent to the skull fracture, probably thus an epidural hematoma, and since it crosses the midline, you think about venous epidural hematoma, see the extracranial soft tissue swelling, a little bit of blood along the anterior folds, and there's a bit of mass effect from that. See blood inside the head, try to put it into a compartment. Is it radiographically acute or not? If you see a sedimentation level, think about hyperacuity, and think of the contra-coup concept for epidural, more coup site. Is it arterial or venous in terms of its origin? And then if you can't figure out what space it's in, say it's space indeterminate. That's a good way to approach it. Here's a patient with a headache. They have diffuse hyperdensity throughout their subarachnoid spaces, so you're worried about subarachnoid hemorrhage, interventricular hemorrhage, and then you can see they have some brain swelling and cerebral edema in addition to that. Their ventricles are too big, and it looks like that they have hydrocephalus as well. So this package of findings typical for aneurysm rupture and subarachnoid hemorrhage, which can cause headache. Usually the history in that case would be worse headache of life, endocarp headache, those kind of things. We have an angionegative subarachnoid hemorrhage pathway, but this usually does yield something in my experience most of the time. Occasionally not, but we do have that pathway as well. In terms of hydrocephalus, could be communicating, could be non-communicating, could be both. Other things in the subarachnoid spaces can cause hyperdensity, meningitis being one of them, but generally speaking, you know, that appearance is usually blood that we saw, especially because of the history. If SAH is peripheral, come up with a differential diagnosis for the peripheral ones, which is, you know, depending on the history, trauma may be one of those as well, but there's a short list differential diagnosis. Companion case, another patient with headache, you can see they have filling defects in their bilateral transverse sinuses. So, these are dural sinus thrombus. And so, oregano granulations can sometimes look like dural sinus thrombosis, but, you know, are they occlusive? Are they propagating? These are more typical of clot and cells, but there is sometimes some difficulty in telling one thing from another. That's where seeing the signal characteristics within the thing itself helps. I'm thinking about looking at, you know, has it gone to the point of making a patient have a venous ischemia, maybe hemorrhagic venous infarction, that kind of stuff. Look for cortical vein thrombosis. So, things that are peripheral, you know, like especially on the SWI, looking for a blooming. I find that very helpful. Here's a patient with myelopathy. You can see that they have complete effacement of CSF around their spinal cord. There may be a sliver of CSF ventrally, but pretty close to severe as far as that goes. That's how I define severe is complete effacement of CSF. So, nearly severe in the front, severe in the back. And then, from a discostic-like complex in the front, ligamentum flavum enfolding in the back. And so, if there was abnormal cord signal, you would upgrade it to critical. That's typically what I do. Trying to figure out where the stenosis is coming from. Is it getting compressed from any direction? What from? And if the cord looks abnormal in terms of decreased volume, increased in 2-2 signal, think about myelomelation. Here's a patient with vision loss. You can see that they have an expanded first link of cella. You have stenosis of the bilateral transverse sinuses. And then, prominence of the CSF spaces along the optic nerve sheath complexes. This is typical for idiopathic intracranial hypertension. Primary differential diagnosis is dual sinus sclerosis. Don't see that here, but it can cause vision loss. So, thinking about low-length cerebellar tonsils, you want to start with, you know, is anything pressing down like a cerebellar tonsil herniation? But think about QRA1. Think about increased CSF pressure, decreased CSF pressure, almost everything as well. So, here's a patient with seizure. Left hippocampus is too small, increased in flare signal, too smooth. So, that's mesial temporal sclerosis. About one out of five chance of having it on the other side as well. The other hippocampus looks normal. So, this patient. So, when I look at cause for epilepsy, seizure, trying to think about abnormal cortex in its normal location or normal cortex in an abnormal location in the supratentorial frame. You think about maybe they have other epileptic mucosa at the same time. Here's a patient with trauma. I see a cervical spine CT scan with a bunch of lytic lesions throughout the visualized bone, basically all over the place. And then they have a path fracture through the base of the DEN. So, type 2 DEN fracture there. This patient either has metastasis or myeloma, most likely. And that path fracture is usually related. can be hard to see on the MRI when looking for fractures, that kind of stuff, so keep looking. In this case, identify the dents fracture, but then also realize that the bones are abnormal in that case. So a couple of summary slides, figure out what's most likely to kill the patient fastest and then work back from there. Make sure you answer the question, say a patient has a headache, like is there anything that could cause headache here. One of my attendings used to say what's the most likely thing it is and what's the worst thing it could possibly be, so I usually like to use that approach as well, and I'm a top three pick one kind of person. Are there any other findings on the imaging that might help you figure out a differential diagnosis or hone the differential diagnosis, especially what I call chart biopsy, bringing out what diagnoses the patient already has, like those kind of things as well. And then I like to say a smart person learns from their own mistakes, a really smart person learns from other people's mistakes. So again, let's move kind of quickly. Thank you for your time and attention and take care. Thanks again. Thank you, Mark. We are going to review the essential points in which interventional radiology is applicable for patients with vascular trauma. I have nothing to disclose. Well concerning the interventional radiology, this is an alternative for treatment of patients and we use basically three mechanisms or alternatives for doing that. The first is valon occlusion and we use that in patients in which we want to do a very quick, fast, life-threatening stopping of the hemorrhage. Most of the time we use transarterial embolization and in this particular scenario we stop the arterial hemorrhage and this procedure is a very effective, safe, and I would say it's very quick if you have the skills, the knowledge, and if you know the equipment and the material you are going to use. The other alternative is to use stent grafts and we use that especially for large vessels. We have to take into account that we don't know what the long-term outcome of these devices are, especially if you apply them in young people. The materials we use most for embolizations are coils and gel foam. And let's review what happens through the different areas in which we can apply interventional radiology in vascular trauma. And the most common probably is the spleen because it's the most common organ affected by blunt trauma, also by penetrating trauma, but most of the time it's blunt trauma. The first indication for imaging is CT. Once we have the angio-CT, we can study and see if the patient has an indication for angiography depending if there is extravasation or pseudoaneurysm formation. This for example is a case in which we demonstrated on a previous CT the active bleeding and then the patient shows in this angiography very proximal from the ciliac artery, basically the origin of the splenic artery. We see the spleen, the fracture, the hematoma displaced in the spleen from the abdominal wall and took in different phases. The arterial phase, you see that, the bleeding, the venous phase. And then in this patient we decide to do a more proximal embolization because we in that way can preserve all the collaterals for the spleen and we can do a very quick and safe embolization in this particular scenario. This is another case, but it's a different one with a six year old boy that you can see the fracture spleen, the hemorrhagic sites, and then we are here more distal and we could go through a micro catheter and be very selective and just to embolize with the areas which are actively bleeding and to finally preserve the spleen. Liver is also injured in blunt and penetrating trauma and injuries could happen in the hepatic arteries, the portal veins, and also in the hepatic veins. And to study that and see how this is happening in particular patient, the CT angiography is the procedure of choice. We have to remember that if we see an active arterial bleeding and the portal vein is patent, we can basically be sure that we can go very fast and if you don't have time, just embolize the artery and nothing is going to happen with the liver. But most of the times we want to be more selective or super selective than in this particular case in which you can see the bleeding, you see the hematoma displaced in the liver, and the active bleeding, we can demonstrate that. And we were able with a micro catheter to put a very small coil and to stop the bleeding. This is another case that as you see, the patient was operated before because of the abdominal trauma, but it was still unstable. You see the hematoma displaced in the liver and this arteriogram, the active bleeding, was profusely bleeding. And then we reviewed the portal vein, the rest of the hepatic veins, and just the artery was bleeding. So we were able to embolize very selective, just the artery that was bleeding. This is another case after a biopsy, also a very specific site of bleeding. And then we could go with a micro catheter and put just a small coil and stop the bleeding and preserve the rest of the liver. Kidney is also very frequently affected. And in this organ, the embolization should be performed as selective as possible. We just bought the gel foam and coils. Most of the time we use coils and also stent graft, like in a case I'm going to show you if there is a large vessel that we want to preserve. Like in this particular case, for example, in which there was a lesion by a penetrating trauma in the left renal vein and the bleeding was there in a small branch. And then we were able to put the stent and stop the bleeding. This is another case, courtesy of Dr. Pontones from Monterrey, Mexico. And in which after a biopsy, you see the arteriovenous fistula communication that he was able to stop very quickly with a coil and very selectively. The aorta is also injured in many cases of automobilistic trauma, for example. And you have to have a very high degree of suspicion for detecting these patients. And most of the time, these patients, they have a checked X-ray. If the X-ray is normal, I tell you, basically this patient, you can rule out that the patient has an aortic aneurysm or aortic rupture in 95% of the cases. But if you have any doubt of what we do in our hospital, most of the patients, they go to CT. And if the CT is normal, it has a negative predictive value of basically 100%. Acute traumatic aortic injury is most of the times is happening in the aortic isthmus, although there are other areas. Like this case, which is courtesy of Dr. Pablo Cobos from Tabasco, Mexico, in which after an automobile accident, the patient had this rupture of the aorta at the isthmus. This is the angio and the reconstruction. And then they put a stent graft and stop and preserve the aorta. One of the branches of the many branches of the aorta, like the mesenteric artery, we have this case in which the surgeons, as you can see there, they put a gastrostomy tube, and they injure one of the branches of the mesenteric artery. And you see the bleeding there. And we were able to go fast with a micro catheter and use some glue in order to stop the hemorrhage. In the pelvic, the pelvic hemorrhage most commonly arises from fracture, bones, and disrupted pelvic veins. Most of the cases is pelvic bleeding, I mean venous bleeding, although there are some cases in which you have branches of the internal iliac arteries that are bleeding. And this is an emergency. The treatment of choice in many areas, in many centers, is external fixation. And this is okay because it supposes the bone surfaces and stop the bleeding, although this is, I mean, there are delays in transarterial embolization in case you want to do that. The indication for that is when you see the active extravasation or the arterial blanche, irregularity or truncation. And there are some other controversial indications. One of the ones that we use most is to treat bleeding, to reduce, I mean, the bleeding venous from venous origin because you reduce, if you stop the arterial supply, you reduce the pressure in the veins to stop bleeding. And these are a couple of cases that we go in the pelvis and you can be very selective and embolize that if you want, but if you want this very quick, just it's like a shower of gel foam and then you can stop that. There is so much collateral veins, I mean arteries and circulation that you can basically, this is another case. You can basically stop the bleeding very quickly if you need to do that. In the extremities, well, we can have arterial transsections, dissections and occlusions and CT angiography is also very sensitive and specific to plan the treatment and the treatment is, as I already showed you, through balloon occlusion, transarterial embolization or stent grafts. So in conclusion, interventional radiography or radiology has much to offer to the evaluation and treatment of traumatic injuries for patients and organ preservation and avoidance of surgery is the main reason for doing this. Nowadays there is a lot of improvement in transcatheter equipment and techniques and we have, as always, to have a solid understanding of the benefits and risks of the different transcatheter therapies to provide patients with the best care. Thank you very much for your attention and now I will introduce Dr. Lamia Jamjoum. She is going to talk about CT of cardiothoracic trauma. Thank you, Dr. Jamjoum. Hello everyone. Today I'm going to talk about CT of cardiothoracic trauma. I have no disclosures and I would like to extend my appreciation to some of my dear radiology professors and colleagues who were very kind and shared with me some of their cases. In this lecture, I'm going to touch on the role of CT in imaging cardiothoracic trauma and show some example cases. A few important facts to keep in mind are that cardiothoracic trauma is the third most common type of trauma, accounting for 25% of trauma-related deaths in the United States, second only to head injuries, with a fatality rate of 10%, highest in patients with cardiac or tracheobronchial esophageal injuries. When it comes to mechanisms, cardiothoracic trauma can result from either blunt or penetrating injuries. A blunt trauma usually results from a blow to the chest, either from the steering wheel in a car accident, or by a blunt object, or less likely a fall from height. On the other hand, penetrating trauma results from stab wounds, gunshots, or less likely faulty instrumentation resulting in perforation of one of the thoracic organs. When it comes to the role of CT in thoracic trauma imaging, it has to be kept in mind that CT is very sensitive and specific, particularly with the spiral capabilities, and it has been credited with changing management in up to 20% of chest trauma patients. CT helps exclude thoracic aortic injury, it's valuable in the diagnosis of the thoracic spine, and it's more accurate than chest radiography for the evaluation of parenchymal injuries. It also improves visualization of tracheobronchial disruptions, diaphragmatic tears, and pneumothoraces. It's always helpful to have an approach when evaluating cases, and one of the approaches I came across and modified a bit is based on dividing the findings into parenchymal, which includes changes in the lung parenchyma, such as contusions and lacerations, and extra parenchymal, which can be divided using the alphabetical letters A to G, and I will go over those in details later in this lecture. Now let's go over a couple of parenchymal findings that you may see on CT. This is a case of trauma in which the initial chest radiograph was unremarkable, however CT clearly showed these rounded consolidative opacities with ill-defined margins in keeping with pulmonary contusions. This is another blunt trauma case in which the CT showed these confluent consolidative opacities, sparing the immediate subplural lungs, one of the features associated with severe pulmonary contusions. Moving along, this patient's CT showed small air-filled cysts within areas of consolidations. This is one of the features characteristic of pulmonary lacerations. When it comes to the extra parenchymal findings, think of the letter A as aortic injury. CT allows visualization of mediastinal hematomas, which is an indirect sign of aortic trauma, but it also can show the actual aortic injuries in some cases, which are considered direct signs. This was a 24-year-old male who presented to our hospital several years following a road traffic accident. The CT clearly showed this calcified-out pouching in the proximal descending aorta at the level of the ligamentum arteriosum in keeping with a chronic pseudoaneurysm. The patient was treated by placement of an endovascular stent to exclude this pseudoaneurysm, and he did very well afterwards. Another trauma case in which CT showed irregularity in the contour of the descending aorta, one of the direct signs of aortic injury. The CT also showed an anterior mediastinal hematoma and a peri-aortic hematoma. Those are indirect signs of aortic injury. Now in this trauma case, the initial chest radiograph showed widening of the mediastinum, a finding that's not specific but should raise concern for vascular trauma. CT was done afterwards and clearly showed the flap of tissue in the descending aorta, another direct sign of aortic injury. The patient also had a conventional angiogram, which showed the same findings. Moving along the same lines, the CT in this trauma case showed a peri-aortic hematoma, and it also showed one of the direct signs of aortic trauma, which is the eccentric thrombus in the descending aorta extending all the way to the abdominal aorta. The patient also had a right hemothorax. In some cases, findings may be even more impressive, as in this patient who had change in the caliber of the proximal descending aorta, and an abrupt cut-off, and also extravasation of contrast into the mediastinum. Unfortunately, this patient didn't make it. Moving along, now think of the letter B as bronchial tree, and keep in mind that in most cases bronchial changes can be very subtle. However, sometimes CT may show the bronchial lacerations clearly. This is a case of penetrating trauma secondary to stab wounds, and the CT showed the discontinuity of some of the bronchi on the right side. It also showed a few parenchymal lacerations. Now think of C as cardiac cord and chest wall. One of the common presentations of cardiac trauma will be hemorrhaging to the pericardial sac, or what we call a hemopericardium, as clearly illustrated in these two cases. When it comes to chest wall trauma, findings that you may see include subcutaneous emphysema, as in this case, or a chest wall hematoma, as in this patient who had a large left anterior chest wall collection with high-density areas in keeping with the hematoma. Now the letter D stands for diaphragmatic trauma, and CT does a good job showing tears in the diaphragm. This is a case in which the patient had a left diaphragmatic tear with a hernia containing small bowel loops, and CT clearly showed the point of interruption in the left hemidiaphragm. Now the letter E should make you think of esophageal trauma. Keep in mind that esophageal perforation is rare, however, if it happens, CT usually shows stigmata of esophageal trauma, such as a pneumo-mediastinum, or fluid collections in the mediastinum, or plural space. This was a trauma case with esophageal injury, and the patient presented with a pneumo-mediastinum. Now if esophageal injury was clinically suspected, dedicated esophageal imaging should be performed. This was another case in which the patient had dedicated esophageal imaging, which showed extravasation of water-soluble contrast in keeping with transmural perforation. Under the letter F, you may consider fractures and fluid in the plura. Fractures, especially rib fractures, as in this case, are the most common type of injury in blunt trauma cases. This is another blunt trauma case in which the CT showed an anterior mediastinal hematoma separated from the vascular structures by a fat plane. Such a finding should direct your attention to other causes of mediastinal hematomas. In this case, it was a sternal fracture. Along the same lines of fractures, you may consider subluxation of joints in some trauma cases. In this patient, there was a manubrious sternal subluxation and an anterior mediastinal hematoma. Plural fluid, or specifically blood in the plural space or a hemothorax, can result from injury to the lungs, chest wall, or sometimes abdominal injury. This is the most common cause of shock in blunt trauma patients. Finally, the letter G should make you think of gas or air in the thoracic cavity. Those may include pneumothoraces, as in these two cases, one showing a small pneumothorax and the other showing a medium-sized pneumothorax. Another type of gas would be gas in the pericardial sac or what we call a pneumopericardium. Or finally, gas in the mediastinum or a pneumomediastinum. A pneumomediastinum can result from different causes. It can be secondary to alveolar rupture with air tracking along the bronchovascular sheath to the mediastinum or what we refer to as the Maclin effect. If the Maclin effect was not the underlying cause of a pneumomediastinum, then you should consider other causes such as esophageal perforation or tracheobronchial injury. Now this was the last case in my lecture and this lecture was the last in this session. Thank you very much for your participation and stay safe.

emergency radiology

trauma imaging

CT techniques

vascular injuries

neurologic trauma

cardiothoracic trauma

interventional radiology

minimally invasive treatments