So, my name is Christina Lebedis, as I mentioned, I'm from Boston Medical Center, and today I'm going to be speaking on blunt pancreatic trauma. The learning objectives over the next 20 minutes are to describe the incidence and mechanism of injury of pancreatic trauma, to identify and grade pancreatic injuries at CT, to troubleshoot pancreatic injuries with MRCP and ERCP, and to understand the management implications of pancreatic injury grading. Pancreatic injuries are rare, and are seen in only about 2% of all trauma patients and 10% of those with other intra-abdominal injuries. Blunt trauma accounts for approximately 60% of pancreatic trauma cases, with the remaining 40% seen in penetrating injuries. It's important to note that although most cases of pancreatic injury are secondary to blunt trauma, those from penetrating trauma occur more frequently on a per case basis. Blunt pancreatic injury typically occurs secondary to deep anterior-posterior compression of the pancreas against the spine, usually in a rapid deceleration injury. The classic scenarios, as depicted here, are seatbelts and steering wheel injuries in adults, and handlebar injuries in children. Traumatic injuries of the pancreas are often difficult to diagnosis, owing to their subtle imaging findings and confounding multi-organ injuries. Unfortunately, the clinical and laboratory findings in these patients are also subtle and nonspecific. Serum amylase levels are in fact normal in up to 40% of patients with pancreatic trauma, and unfortunately, the pancreas can appear normal within 12 hours of injury at CT. Thus, maintaining a high index of suspicion and repeating a CT in 24 hours may be warranted to make this diagnosis. With respect to clinical outcomes, it has been shown that the treatment of pancreatic injuries within 24 hours is associated with decreased patient morbidity and mortality. Conversely, a delay in diagnosis can lead to an increase in patient mortality as high as 17 to 21%. The pancreas is an accessory digestive gland with an exocrine and endocrine function located in the anterior perirenal space of the abdominal retroperitoneum. Fluid and hemorrhage in this space, denoted here by the asterisks on this axial contrast enhanced image, is a finding associated with pancreatic injuries. With respect to the American Association for the Surgery of Trauma, or AAST, pancreatic injury grading terminology, the SMV is used as a dividing line. The proximal pancreas is located to the patient's right of the SMV, and the distal pancreas is located to the left. I would issue a warning here that this proximal and distal terminology is ambiguous and discordant among specialties. In fact, in the literature, there's about a 50-50 split in the identification of the proximal and distal pancreas among our colleagues in the hospital. So this terminology can be dangerous to use in a report. So I would advocate that we use our usual pancreatic head, body, tail terminology in the report. Multimodality imaging plays a vital role in the diagnosis and management of pancreatic trauma, as clinical findings can be nonspecific. Contrast enhanced CT plays the primary initial role for demonstrating signs of pancreatic injury. MRCP is used for problem solving and treatment planning. As we all know, it provides a noninvasive assessment of the pancreatic duct integrity. And compared with ERCP, MRCP has the advantage of detecting abnormalities of the pancreatic parenchyma and the surrounding structures. ERCP, as we know, also provides exquisite assessment of the pancreatic duct to make sure that it is intact. And although it's invasive, it does allow for treatment of pancreatic duct injuries with stenting. Although there is no universally agreed upon protocol for trauma CT imaging, the predominant technique used is a multi-phase contrast enhanced protocol in the late arterial and portal venous phases with selective use of a five-minute delayed scan. This protocol contrast is not routinely used in trauma patients. So how does CT perform? Data from the surgical and radiology literature on CT performance in this realm demonstrates that CT has a limited sensitivity and specificity for the detection of pancreatic injuries. You can see here we have a suboptimal sensitivity of 79% and a specificity of only 62% for the diagnosis of main pancreatic duct injuries. So the reasons for this performance are multifactorial and include the fact that pancreatic injuries are uncommon, so we're not used to looking for them. They're often subtle, particularly in thin individuals. Patients often have multi-organ injuries. And the findings of pancreatic injury on CT may take hours, days, or weeks to develop as the release of pancreatic enzymes kind of work their magic. So this table splits the CT findings of pancreatic injury into direct and indirect findings. And we often rely on a combination of multiple findings to arrive at the diagnosis of pancreatic injury. So in this example, we see pancreatic swelling at the junction of the pancreatic body and tail with a laceration that expands the entire thickness of the parenchyma, which implies main pancreatic duct involvement. This was later confirmed at ERCP after damage control laparotomy. Here are two examples of indirect imaging signs of acute pancreatic injury. The top image demonstrates inflammation of fluid in the region of the anterior perirenal space as indicated by the yellow arrow, while the bottom image shows peripancreatic fluid interdigitating between the splenic vein and the pancreas. And I would pause here for a moment. This is a very helpful imaging finding to lock onto fluid here between the splenic vein and the pancreas. So depicted here is the AAST pancreas injury scale, which is the most widely used grading scale for pancreatic trauma. As with the other AAST injury scales, ascending grades are associated with more severe injuries. Low grade injuries are comprised of grades one and two, while the higher grade injuries are three through five. And I'll just take a moment to walk through this. So grade one injuries are minor contusions or superficial lacerations without duct injury. Grade two are major contusions or lacerations without duct injury. Grade three are distal transections with parenchymal injuries with or without duct injury. Grade four, see we have involvement here of the proximal pancreas. And we can have involvement of the ampulla. And grade five is massive disruption of the pancreatic head. As with other AAST grading scales, if there are multiple lower grade injuries, you can advance the final grade up to grade three. For example, if a patient has, say, both a grade one and a grade two injury, I can advance the pancreatic injury grade to a three. Or say I have a patient with two grade two injuries, I also can advance that patient to a grade three injury. So there are limitations to the double AAST pancreas injury scale. Specifically, vascular injury is not included in the double AAST classification, but it is important in determining patient management and predicting patient outcomes. In these two axial images, there's a 20-year-old man, status post MVC, who had multi-organ injuries, including a grade four liver laceration and a grade two splenic laceration, which I've not shown. These axial images demonstrate a large contusion involving the pancreatic head, representing a grade two pancreatic injury. And within this area, you'll also see an area of active vascular contrast extravasation from the GDA. This patient required emergent exploratory laparotomy for ligation of the GDA. In hemodynamically stable patients, the main pancreatic duct integrity is the main factor determining patient outcome. Main pancreatic duct involvement can be inferred based on the depth of a parenchymal laceration. With a laceration involving more than 50% of the parenchyma to have a presumed main pancreatic duct injury, whereas less than half of the pancreatic parenchyma involved, we presume that there is sparing of the main pancreatic duct. I would offer a word of caution with this. Be careful when you're applying this 50% rule to the pancreatic head, where the main pancreatic duct does course more posteriorly within the pancreatic parenchyma. Multiplanar and curved planar reformats are essential at CT imaging to get a look at the main pancreatic duct. And as we all know, MRCP and ERCP provide more direct assessment of main pancreatic duct assessment. So here's an assessment of a curved planar reformatted CT image in the coronal plane, which demonstrates the pancreatic duct to best advantage. Again, remember that these are available. They do require some time to make, but they can be of tremendous value in assessing the main pancreatic duct. I wanted to go through a couple of pitfalls. So here's an 80-year-old woman's status post MVC. This contrast-enhanced axial CT performed demonstrates two adjacent linear hypodensities within the body of the pancreas, both concerning for pancreatic lacerations involving more than 50% of the gland. So at surgery, there was actually no injury to the pancreas. So this pitfall is actually fluid in the clefts of the pancreatic parenchyma from fluid resuscitation. Here on images from the same scan, we see that there's periportal edema, and the IVC is full, supporting this diagnosis. In this image, we see another example of fluid in the cleft of the pancreatic parenchyma. Again, use your multiplanar reformats. You can actually make this diagnosis in concert with the coronal image, as shown here. If you're not sure, get an MR or an ERCP. So as in all trauma patients, management is multifactorial and governed by the most emergent organ injury. With respect to pancreatic trauma management, the integrity of the main pancreatic duct is of paramount importance. Pancreatic vascular injury, as we've seen, is also very important to diagnose. Lastly, we rely on the AAST pancreatic injury grade. So here we have a patient on the left who suffered a gunshot wound, and we can see at ERCP that the patient has main pancreatic duct involvement. The CT on the right shows a patient who was in a motor vehicle collision, and although a pancreatic laceration was initially thought to be present, they were managed conservatively. I've highlighted here that the patient has actually a liver injury. So going through some cases of patient management, here we have a 30-year-old who sustained blunt trauma from a motor vehicle injury, and she actually has a vascular injury within the pancreas. This was managed by IR. When she went to ERCP, we can see that there's actually a laceration of the main pancreatic duct, which required pancreatic jejunostomy, ultimately. This is an example of a main pancreatic duct transection at MR. On CT, we were worried that the main pancreatic duct was involved, and at MR, we again see this through-and-through transection of the pancreas. The patient was also managed operatively. In this example, we have another pancreatic vascular injury, active extravasation. This patient was taken to emergent pancreatic jejunostomy. So here's an unknown case. This is a real example in kind of putting all the pieces together. So this is a hemodynamically stable 22-year-old male who was involved in a motor vehicle collision. So starting with the spleen, we see that there is a 4-centimeter laceration compatible with a grade 3 splenic injury. Moving on to the liver, we see multiple liver lacerations. There's no vascular injury, but it seems that at least 25 percent of this lobe is involved, yielding a grade 4 liver injury. And then as we move towards the pancreas, we see that there's peripancreatic fluid, and there's a subtle laceration here, which brings us to a grade 3 injury. This was confirmed at ERCP, where there is main duct involvement, and the patient was treated. Complications are seen in up to half of patients who have sustained pancreatic trauma. The most common complications are listed here. Pancreatic fistula, abscess, and post-traumatic pancreatitis top the list. This is an example of a pancreatic fistula. This patient sustained multiple gunshot wounds. He had an exploratory laparotomy, and you see his open abdomen. There's a bullet sitting in his pancreatic tail at the initial post-laparotomy CT. Three weeks later, he was scanned again, since he was not doing well and had a persistent fever, and we see a fluid collection at the operative site in the pancreatic tail, which tracks superiorly into the left pleural space. So this is a pancreatic fistula to the left pleura. This was successfully treated with percutaneous drainage. This is an example of post-traumatic pancreatitis. So again, a motor vehicle injury patient with multi-organ injury. We see extensive peripancreatic fluid on the initial CT, and linear hypodensity subtle along the pancreas, which was concerning for a laceration. At ERCP, the main duct was intact. At surgery, no pancreatic laceration was found. And given the extensive peripancreatic fluid on imaging, and the persistently increased serum amylase levels, post-traumatic pancreatitis was suspected in this patient. This is an example of a pseudocyst. There was an injury of the distal pancreatic body. At surgery, a hematoma was found here and evacuated. And on later follow-up imaging, a pseudocyst developed at this site. Imaging obtained a couple of years later for different reasons show complete resolution of this imaging finding. So in conclusion, pancreatic trauma is rare. The most important determinants of patient outcome in hemodynamically stable patients are the time to diagnosis and the integrity of the main pancreatic duct. Identifying pancreatic injuries is difficult. Use everything at your disposal to make this diagnosis as the patient's morbidity and mortality relies on it. Employ a multi-modality approach. If you're not sure, bring the patient back for a repeat CT. Pursue an MRCP. Ask your GI colleagues to do an ERCP. So with that, I thank you. My topic for today is bowel and mesentery trauma. This is a pretty broad topic, as I will touch on both penetrating and blunt trauma to the bowel and mesentery. So I thought I'd show you a few cases and companion cases that have taught me a lesson either the hard way or the easy way. And hopefully you can learn from them too. So this is my first case, a patient who is intoxicated. It's deer hunting season in Missouri and he was doing the same, tripped and fell in the woods and struck his abdomen. He was brought to our hospital and had this CT scan which demonstrates a small volume of free intraperitoneal fluid. Now we know patients who have been volume resuscitated can have varying amounts of free fluid, but this is more than we expect to see. There's fluid around the liver and spleen. There's fluid in the root of the small bowel mesentery and some in the pelvis as well. So I said this is a concerning amount of free fluid, possible bowel injury, recommend surgical consultation, which they did. And they also noted by way of doing so that the patient had hematuria. So retrospectively, this patient's bladder, although decompressed, is thickened. There's periviscular fat stranding and heterogeneous material in the bladder lumen. The subsequent CT cystogram demonstrated the cause for the free intraperitoneal fluid, not as a bowel injury, but rather as a rupture of the bladder dome with leakage of contrast into the intraperitoneal space and an adherent clot within the bladder lumen. Now you would think I would learn my lesson, but a few weeks later, this patient came in. In fairness, now with free intraperitoneal gas as well as free fluid, I searched for a bowel injury but couldn't find one. But nevertheless, given these findings, I said concerning for potential bowel injury, recommend surgical consultation, which was done. And they noticed that the patient's Foley catheter was draining blood. And at that point, asked for a CT cystogram, which, no surprise, demonstrated an intraperitoneal bladder injury with leakage of contrast into the intraperitoneal spaces around bowel loops and dependently layering within the pelvis. So keep in mind that we're trained to think of free fluid and free gas as being a bowel injury, but keep in mind that bladder injury can look very similar, especially in patients who have a Foley catheter that can introduce gas. In fairness, I do think this can be hard. This can be, this is a patient with a blunt, small bowel injury. Notice that the lung windows, which can be quite helpful in these cases, demonstrate free intraperitoneal gas antidependently, but also free fluid within the pelvis. This patient did not have hematuria, went to exploratory laparotomy, and had bowel injury confirmed. Be skeptical about gas outside the lumen of the bowel and the bladder. This is a patient who came in with blunt trauma, had several organ injuries, including rib fractures, and has extraluminal gas in the upper abdomen. Patients lying on their backs tend to have gas collect towards the anterior aspect of the abdomen, but if they've been semi-upright, that gas can be trapped around the liver or the diaphragms. But this gas is too perfect. It's taking this curvilinear appearance and tracking right along the pleura and the diaphragms, and this person did not have a bowel injury, but rather has bilateral pneumothoraces that have mimicked pneumoperitoneum by having some of the gas trapped near the upper abdomen. This was initially read as a bowel injury because of the suspected pneumoperitoneum, so it's important to remember anatomic spaces when it comes to diagnosing free fluid and free gas in particular. Here's another patient with extraluminal gas in the lower abdomen. This patient has gas that's centered in the pelvis. Notice though that it's not really layering antidependently, rather it looks septated. It's following extraperitoneal spaces of the abdominal wall and near the rectus sigmoid junction. This is another patient with a bladder injury. It's a patient who is misdiagnosed as having pneumoperitoneum, but in this case, this is all extraperitoneal gas, again introduced by the Foley catheter. This patient does not have a bowel injury. They do not need to go to surgery. They need to have a catheter in place to let this extraperitoneal bladder injury heal, and that can be confirmed with CT cystogram, but again, paying attention to the distribution of the gas as well as the appearance. The septation and these septations here might remind you of pneumomediastinum. It's a nice reminder of the continuity of the mediastinum with the extraperitoneal spaces of the abdominal wall as well, and that they can look quite similar to one another. Here's my second case. This is a patient who was in a motor vehicle collision. This was a restrained driver. Quite obviously, this patient has an abdominal wall defect. They have a traumatic hernia through their inferior lumbar triangle. They also have a couple of other subtle findings that are perhaps even more important to observe. Notice that they have free intraperitoneal fluid in the pelvis, and that this fluid is closer to the attenuation of skeletal muscle than it is to the urine. There's also free intraperitoneal fluid in the sigmoid colon mesentery, sort of forming an outpouching of fluid right next to the bowel, and there's some subtle focal thickening of the distal sigmoid colon. This patient has a traumatic lumbar hernia, but they also have a degloving injury of their sigmoid colon mesentery. The important thing to remember about traumatic lumbar hernias are not that the patient received trauma to the left flank. It's that their intraperitoneal cavity was squeezed so hard that they burst their muscle. So it stands to logic that if it can generate enough force to rupture the muscle, the bowel is clearly at risk as well. Let's look at a couple other examples. Here's a less subtle bowel injury associated with a traumatic lumbar hernia. Notice this patient has not just the hernia, but extensive abdominal wall hematomas and contusions. So if you're reading on a busy night and you notice a patient who has this much abdominal wall injury, you should go back through the scan again and look at the bowel and mesentery because they're at high risk for injuries. There is not subtle hemoperitoneum within the small bowel mesentery and within the pelvis, and even some locules of contrast extravasation. So this patient is clearly actively bleeding from a mesenteric injury and needs to go to surgery. This is a much less subtle example of a bowel injury associated with traumatic lumbar hernia. In this case, not only has the mesentery been injured, but the entire left colon has been degloved. It has ruptured into the abdominal wall. This is obviously a very specific finding for bowel injury, but not very sensitive. I spent a bit of time talking about free intraperitoneal gas and association with bowel injuries. We certainly should look for it, but it is really seen in a minority of blunt bowel injuries. So if you're waiting to see pneumoperitoneum to diagnose a bowel injury, you're probably missing a lot of bowel injuries. But nevertheless, this is a nice example of a severe injury associated with an abdominal wall contusion and rupture. Again, traumatic lumbar hernias result from a compression or crush-type injury, often with a lap belt or even an airbag. That increased pressure causes blowout of the muscles, has up to 50% association with bowel and mesenteric injuries. And the risk of bowel injury increases with the severity of the hernia. This of course is not limited to traumatic lumbar hernias. This is a patient who has a CT seatbelt sign, a nice hematoma and contusion across the midline where the lap belt was sitting. This person also has hemoperitoneum. If you just saw hemoperitoneum and you didn't have a solid organ injury, you would already be worried about a bowel or mesenteric injury in this patient. But look at the direct signs of bowel injury here. There is thickening and hypo-enhancement of the jejunum. There is loss of distinction between the bowel wall and fluid and blood in the mesentery. It's a useful sign, not just in trauma, but in patients for whom you're worried about ischemia. You should be able to differentiate the bowel wall from either intraluminal or extraluminal fluid or blood products, and when you start to lose that distinction, you should be worried that that bowel is not vascularized normally, and this was devascularized bowel injury at laparotomy. Here's another case of a patient with a bowel injury, this time delving into some penetrating trauma. Let's look at the findings here. This patient was stabbed in the right lower quadrant. You can see that there is a hematoma and active bleeding in the subcutaneous tissues. There's thickening of the underlying rectus muscle, and there's hemoperitoneum. In the path of the injury, there's thickening of the cecum and the ileum, so this is a pretty clear-cut case of peritoneal violation with high suspicion for bowel injury in the setting of a stab wound, and unfortunately, this is about as clear as stab injuries can get on CT because most patients don't come in like this. This is a patient who unfortunately repeatedly stabbed himself with objects and came into the ER with this knife still in place, and so we knew exactly how deep the injury went, but that's a minority of cases, right? There's a reason why I've had this case for 10 years, because it almost never happens. This is more typical. This patient was stabbed in the epigastrium. Here's the stab wound entry site here, and you can see that there are very trace amounts of free blood. There's free blood behind the transverse colon and its mesentery. There's free blood in the left pericolic gutter. Note that there's no free intraperitoneal gas. There's really no bowel thickening, but simply knowing that this patient was stabbed here and somehow resulted in blood behind a loop of bowel here, this patient has bought himself an exploration because we're concerned about a very subtle stab injury to the colon. This is a patient who shouldn't give us too much difficulty in diagnosing a bowel injury. This patient was shot with a path that started in the left hemipelvis and ended in the abdominal wall in the right upper quadrant. I tell our residents when they're beginning to take call that you really need to be closely attentive to the trajectory of bullet wounds and either find the entry and exit wound or the entry and bullet where it lies. And then connect the dots. In between these two sites are hemoperitoneum and a focally thickened loop of bowel in the path of the bullet with perhaps a small focus of active bleeding. This person had several enterotomies at surgery, but we don't need a lot of deliberation to make this diagnosis on CT. Now traditionally, the old literature, the very first articles that came out for CT and penetrating trauma were strong advocates for triple contrast, IV, oral, and rectal contrast. And perhaps that was due to limitations of the scanner. But increasingly, we know that that's not being used as much. Depending upon the article you read, using IV contrast only has variable and often similar accuracy compared to triple contrast. It's faster to do IV contrast only, especially in critically ill patients. And it doesn't preclude you to go back and use enteric contrast for follow-up or problem solving. This is a little bit of a controversial topic, and it's driven in most places by physician preference. In my judgment, based on the literature and our experience, the best approach is perhaps a little bit more nuanced. We don't start with triple contrast for penetrating trauma, but we do use it for problem solving in stable patients. Here's an example where I think it was quite useful. This patient was stabbed in the right flank. You can see that he has blood and extraluminal gas in the retroperitoneum near the right colon. I can't tell you whether or not the colon's injured based on this. I can simply tell you that the skin was violated, that there's blood and gas in the soft tissues, and the colon is in harm's way. So this is a patient who is a good candidate to get rectal contrast, which nicely demonstrates a focal leak from the posterior right aspect of the right colon, and so this patient needs to go to surgery. They shouldn't be managed conservatively, and in this case, I think this is quite a useful problem solving tool. Here's a patient who was shot through the pelvis. You can see that there's extensive gas within the left gluteal muscles. Notice also these bullet fragments as well. I'll get back to that in a second, and that the bullet ultimately lodged immediately to the right of the rectum, and there's extra peritoneal blood and gas. Certainly could have a rectal injury. It makes a difference whether there is or not, because if we have a relatively low suspicion, the surgeons might do an anoscopy or sigmoidoscopy to look at this. If we have a high suspicion for injury, they may take them directly to surgery. So we gave rectal contrast here, and you can see that there's no leakage of contrast from the bullet site right next to the rectum. They did a proctoscopy and saw no injury, and this patient was managed conservatively. In this case, we were also glad that we didn't use rectal contrast to start, because of all these high attenuation fragments out here in the path of injury. If you give contrast at the beginning, it becomes more tricky to interpret. Are these coming from a leak from the colon, or are they intrinsic to the injury itself? In this case, I think we did the right thing by choosing the protocol we did. So in subtle patients, in stabbed wound patients, and in those for whom there's an equivocal injury, this can be useful. But I would argue that the patient who has multiple bullet wounds through the peritoneal cavity probably does not benefit from enteric contrast. My last case here is a pedestrian who was struck by an automobile. You can see that there is blood where there shouldn't be. There's blood in the small bowel mesentery near its root. There's blood in the transverse colon mesentery. There's no active extravasation. There's no hemoperitoneum. There's no bowel thickening or hypo-enhancement. But nevertheless, the quantity of blood here made me concerned. We said concerning for mesenteric injury. The surgeons went and examined this patient, and to my surprise, they were successfully managed conservatively. Now the AAST does have criteria for grading bowel and mesenteric injuries, but they're really more based on operative findings rather than CT findings. And so this taught me, though, that most, that not all bowel and mesenteric injuries are created equal. Here's another case of a relatively subtle mesenteric injury, in this case along the left colon. It really looks like epiploic appendagitis, right? There's this tubular outpouching containing fat near the descending colon. There's a central dot sign here, or a thrombose vessel that you can see. But this person had focal pain there that developed right after a motor vehicle collision. So this is a traumatic epiploic appendagitis, again, sort of a very mild mesenteric in quotes type injury. Here is a patient with hemoperitoneum. As I mentioned earlier, if you see hemoperitoneum and you don't see a solid organ injury, you need to go back and look for a bowel or mesenteric injury. In this case, this patient did not just have blood around the liver and spleen and the pelvis. Notice the sentinel clot here in the pelvis and along the right hemiliver, but there's also this focal triangular collection of blood in the mesentery. This is not specific for mesenteric injury, but it's an odd distribution for generalized hemoperitoneum. And it can be a clue to you that the mesentery may be the source of the bleeding. In this case, the person had several cirrhosal injuries of the small bowel. Here is a patient, again, multiple abdominal wall contusions, in this case, active bleeding in the small bowel mesentery with hemoperitoneum. In many of the solid organ grading systems, we will talk about the presence of a vascular blush, be it a pseudoaneurysm or an active extravasation. Equally important to note within the small bowel mesentery as it conveys some suspicion that the bowel can be devascularized and this patient needs to be explored. Now personally, I don't find the distinction between a small bowel mesenteric pseudoaneurysm and an active extravasation to be very helpful. One, because either feature tells you that there is risk for devascularization and bowel injury. And two, they sort of exist on a spectrum. Here is a patient who got a multi-phase scan actually after small bowel surgery and concern for bleeding. This is arterial phase. This is portal venous phase. There's a rounded collection of contrast here that doesn't change shape or spread out or substantially differ between the two phases. So this is a pseudoaneurysm, but it's also accompanied by an increasing puddle of extraluminal contrast in this hematoma. So this person has both the mesenteric pseudoaneurysm and active bleeding, but to me, they both imply a hole in an artery that is in a different stage of containment, if you will. Also remember that the colon has its own mesentery and that distribution of blood products helps you be more specific about where the injury is. In this case, the injury is manifesting with a large amount of blood in the transverse mesocolon with a small focus of pseudoaneurysm here. This was a degloving injury of the transverse colon, kind of a tough anatomic space because it's near the root of the small bowel mesentery, but by accurately demonstrating the distribution of the injury, you can help guide the surgical exploration. So a few points to sum up here. We should be mindful about extraluminal gas and fluid. Where is the distribution of the fluid and gas? And should be thinking about something else like a bladder injury potentially or an injury in the pleural space. Look at your abdominal wall. It can be a clue this patient has sustained major trauma and you should be a little bit more careful about their bowel and mesentery. Mesenteric contrast may not be needed in all penetrating trauma patients, but consider it for problem solving or equivocal cases and not all mesenteric injuries are created equal. Thank you so much for your attention. Good morning everybody. All right. Well, I am Dr. Carrie Hoff. I am going to be talking today about splenic trauma. So our objectives today are to review the function and the anatomy of the spleen. We're going to discuss the optimal imaging strategies for splenic injury detection. We're going to review the AAST grading scale for splenic injury with particular attention to the 2018 update. And then finally we'll discuss some treatment options for splenic injury. So first of all, let's review a little bit of the splenic anatomy and splenic function. So the spleen is actually the largest lymphatic organ in the body. Now if you remember back to med school when you learned about the spleen that there's red pulp, there's white pulp. The white pulp actually is more involved with white blood cell production and antibody production, whereas the red pulp is more in tune with filtering the blood and removing old red blood cells, phagocytosis, those kind of things. So this, again, this is an important immunologic organ. I think, you know, initially it was felt that you could remove the spleen and there was really very few consequences. It was sort of a non-essential organ. And I think the table sort of really turned on that, particularly when they were doing splenectomies and trauma and they noticed that a lot of children were coming in in fulminant sepsis post-splenectomy. So then we started to really think again about maybe we should try to preserve this as much as we can. So the spleen is actually a highly vascular organ. It's made up of usually around five segmental arterial branches. And remember on the sinusoidal capillary level that these are discontiguous kind of capillaries. It's not just fenestrated, but there's actual gaps in the capillaries because we need to be able to get those immune cells back and forth, the antibodies back and forth. So it's a different capillary bed than what you see in other organs in the body. In addition, it has a very expansile, thin connective tissue capsule. So think about this. We have a highly vascular organ that has a very thin capsule. This seems like it could be problematic in the traumatic setting, and indeed it is. In addition, it is located in the left upper quadrant adjacent to the left ninth through eleventh ribs. So all of this really contributes to it being the most commonly injured abdominal solid organ in blunt trauma. So what is the optimal imaging strategy for splenic injury? Well, first of all, most of these patients are going to come into the trauma bay. They're going to get their initial chest X-ray and pelvic X-ray. And while it's true you're not really going to see, you know, you can't really see the solid organs while on a chest X-ray, but you can see left rib fractures. And if you see displaced left rib fractures on a chest X-ray, that can clue you in that maybe this patient, when you get to the cross-sectional imaging, is going to have splenic injury. Typically our patients will get a FAST scan done in the trauma bay, and that's usually physician performed by our ER staff or trauma staff, and that's basically looking for perisplenic fluid, which can, again, clue you into potentially a presence of a splenic injury. And then they come to us in radiology, which is really where we can really make the definitive diagnosis. So all of our hemodynamically stable patients, and indeed some of our hemodynamically somewhat questionable marginal stable patients, also come to our scanner. And we do arterial and portal venous phase images on all trauma scans. We do arterial from basically the neck to the proximal thighs, and then we go back into a portal venous phase, kind of basically from just above the solid organs to the upper thighs as well. And arterial and portal venous phase images are super, super important to have both. So you can see here the images on the right. The top image is an arterial phase image, and it kind of has this, again, sinusoidal appearance where it's a heterogeneous. There's these areas of low attenuation, kind of a ring and arc pattern, and that can really obscure the parenchyma. However, the arterial phase is really, really, really key for identifying vascular injuries. So in one study, 59% of vascular injuries were only seen on the arterial phase. So if you're not getting an arterial phase, you're missing 59% of vascular injuries essentially. However, portal venous phase images are also important too, and as you can see in the image on the right in the bottom, that that's when your organ really becomes very homogeneous in appearance, and you can really easily see where those lacerations lie. Nuclear medicine, MRI, really not any much use for that in the acute setting. However, I did want to say just a couple words about contrast-enhanced ultrasound. So this may be something on the horizon. I don't think we know yet exactly how we'll be implementing this. Possibly in low-grade trauma, maybe patients that come in that only have had isolated left upper quadrant injury or isolated left upper quadrant injury. Maybe we're going to be doing this in the battlefield or in rural settings to try to triage patients for who might need to come in to a higher level trauma center and relieve higher levels of care. But contrast-enhanced ultrasound uses a stabilized micro-bubbles. These are, they're actually one of our second generation agents at this point in time. They are encased in a phospholipid shell. They do remain intravascular, so this is purely an intravascular agent. This does not intradigitate into the interstitium like some other contrast agents do. This is, it does degrade and then it's simply exhaled. Very well tolerated with a very low reaction rate. Now some studies have shown similar sensitivity and specificity to multi-detector CT with up to around 95% in Europe and Italy. I'm actually in a clinical trial right now that I was hoping to show you some amazing images from, but we're not unblinded yet. I don't know that we'll be quite this high, but maybe next year I'll have a little bit of an update on that. But they actually had 95% sensitivity and specificity, which is actually pretty good. But you can see all the same injuries on contrast-enhanced ultrasound that you can on CT. So you can see active bleeding in the early phase. You see micro-bubble extravasation within the peritoneum or retroperitoneum. You can see lacerations, which tend to be very well demarcated. They're non-enhancing areas. This is on the venous and the portal venous late delayed phase. And you can also see hematomas, which are these non-enhancing heterogeneously hypoechoic areas. So unfortunately this is an image I had to take from the literature, and you can see the image on the upper left. That's just your regular B-mode image. I don't see a lot of perisplenic abnormalities there, but when you go to the contrast-enhanced ultrasound on the top right, you can clearly see that there is a defect through that that's a laceration that corresponds to the images in the CT that you see below. So what are the types of splenic injury? Well, we can sort of separate them into three major categories. So we can have lacerations. We can have hematomas. And this is both subcapsular hematomas or interparenchymal hematomas. And then what we'll be spending a lot of time talking about today are the vascular injuries. So these can be divided into contained vascular injury, which are your pseudoaneurysms and your AV fistulas, as well as active splenic hemorrhage, which can either be confined to the splenic capsule or can be just frankly bleeding into the peritoneum. So we grade these injuries based on the American Association for the Surgery of Trauma Splenic Injury Scale. This was developed in 1989 with some subsequent revisions, the most recent in 2018. So this is a scale from grade 1 to 5. And I think sometimes we forget, too, that surgeons and pathologists can also grade these. This is not just simply an imaging grading scale. And multiple injuries can be present in a spleen. And you can advance multiple lower-grade injuries up to a grade 3. So if you have a grade 1 and a grade 2, you can advance that up to a grade 3. You can't advance beyond that. So even if you have four 1-centimeter lacerations, you're still going to cap at a grade 3. So these are our peritoneum or ab fistula. These are our contained vascular injuries. These are focal collections of vascular contrast that decrease in attenuation with delayed imaging, which is in contradistinction to active bleeding, or in this case, active splenic hemorrhage, where the contrast actually increases in size or attenuation on your delayed phase. So starting with grade 1 injuries, so these are very small subcapsular hematomas, less than 10% of your surface area, or small parenchymal lacerations, less than 1 centimeter in depth, or capsular tears. And again, these are the same whether you're looking at it operatively or pathologically as well. So the images on the left here show a small subcapsular hematoma, less than 10% of the surface area. And note, too, in this case, that the patient did have left-sided rib fractures. So that, in and of itself, when we see that, we're automatically thinking this patient is at a higher risk for a splenic injury as a result. And then images on our right here showing a very subtle splenic laceration, which is less than 1 centimeter. And there is some free fluid inferior to the spleen. So sometimes these can be very hard to find, these low-grade injuries. And so I think it's very important in these cases to always look for your secondary signs. Like in this case, a little bit of infrasplenic blood products or free fluid can really clue you in that you need to go back and look closer. Maybe you need to go to your NPRs and look again, look at both of your phases of imaging. And I will say, too, that for the surgeons in the OR, it's very easy for them to see these small, less than 1 centimeter lacs, or even capsular tears. Sometimes capsular tears, we can't even see them on CT. Even if you see the op report, you go back, you can't always find them. Again, some of these that are really, really tiny, we're just not going to see. And that's probably OK, because the clinical significance is pretty low on those. So moving on to AAST grade 2 injuries. So these are a little bit larger subcapsular hematomas encompassing between 10 and 50 percent of the surface area, interparenchymal hematomas less than 5 centimeters, or parenchymal lacerations in the 1 to 3 centimeter range. And again, this is the same for surgery and pathology as well. So images on the right, or sorry, on the left here, showing subcapsular hematoma that's 10 to 50 percent of surface area, so a little bit bigger than that last example. And then images on the right showing a laceration, which is a little bit deeper. Now you'll also notice this case has a lot of perisplenic and even some gastrosplenic fluid. And that was actually not blood. So this patient was actually a combination blunt and penetrating injury, and it was actually a bicycle accident. So there was a handlebar injury. And then unfortunately they landed somehow on a, like a branch, and basically impaled themselves and had a small bowel perforation as a result. So moving to AAST grade 3 injuries. So these are even larger subcapsular hematomas. So when you're greater than 50 percent of your surface area, or ruptured subcapsular or interparenchymal hematomas, the one different caveat for surgeons is that if they can actually see an expanding hematoma when they're in the OR, that's a grade 3. We can't obviously see that just because they're physically looking at it. And then also a little bit larger lacerations, greater than three centimeters. So images on our left here show a circumferential subcapsular hematoma, which as you can see is greater than 50 percent. This patient also had a small laceration. But even though there's sort of multiple injuries in this case, remember we can't really advance beyond a grade 3. So this is still a grade 3. And then images on the right here showing a through and through parenchymal laceration greater than three centimeters, with a lot of perisplenic hemorrhage as well. Okay, so coming to the grade 4 and grade 5 injuries. So this is really where radiology takes center stage here. So this is actually a key 2018 revision as well, that any injury in the presence of a splenic vascular injury or active bleeding confined within the splenic capsule, that's your grade 4 injury. Now surgeons can't see this. They don't have contrast. They're looking at the organ, right? We are seeing inside the organ. This is where we really can make a difference and get the patients to appropriate management quickly. So here we have an AAST grade 4 injury. The two images on the left are arterial phase. The two images on the right are portal venous phase. And we can see these little round collections of contrast materials, so probably some pseudoaneurysms. But then on the portal venous phase, we actually see that these are spreading out into this large subcapsular hematoma. So this patient went to angio. And you can see here in the first image on the left that there's that little pseudoaneurysm. And then we have this active extravasation of contrast. They did undergo treatment with gel foam and coil embolization. And on the follow-up scan seven days later, you can see the expected evolving changes. So there's a little bit of gas you can see there centrally. And that's a pretty expected finding. Because remember, this patient had frank coil placement, right? So the blood flow has actually stopped. You're also going to see, usually in these cases, I think sometimes it looks worse before it looks better. For one thing, your parenchymal might be a little heterogeneous. Because again, we've cut off some of the blood flow. The injuries themselves are going to have evolved. The blood products are going to evolve. So again, sometimes I think they actually look worse before they start to look better after treatment. OK. So moving on to AAST grade 5. So again, another area where radiology really is driving the treatment decisions in a rapid fashion here. So any injury in the presence of a splenic vascular injury with active bleeding that extends beyond the spleen into the peritoneum is going to be a grade 5. So remember, grade 4, that's going to be contained surrounding the spleen in the splenic capsule. And then grade 5 is when you're extending beyond the splenic capsule into the peritoneum. Also, shattered spleen is another grade 5 injury. And what the surgeons and pathologists use is basically just a devascularization. So here we have a case of an AAST grade 5 injury. So top images are arterial. Bottom images are portal venous. And you can even see on the initial arterial phase that there's extravasation from something. I mean, you can't really tell where it's coming from. Is it coming from the spleen? Is it coming from the adjacent, is it like a mesenteric vessel? And then you can also see that there's probably a little sooner aneurysm there as well. And then when we go to the portal venous phase images, there's quite a bit of active contrast extravasation that we can see here. And when this patient also went to angio. And so here you can also see that there's this large area of extravasation. And then the contrast is sort of flowing out off into the breeze adjacent to that as well. But what's also kind of cool about this case is that you can see multiple little tiny round collections of contrast. This patient also has multiple little pseudoaneurysms. And I want you to keep this in your mind for two slides from now. We're going to talk about this sort of appearance again. This patient also underwent treatment. They actually had gel foam and microvascular plug placement. And I did just want to show one example of a shattered spleen. So I didn't even annotate this because for when you really get to this grade five shattered spleen, what I used to tell my residents is if you don't see the spleen on the wall behind the patient in the trauma bay, it's not a grade five. So these, that's in jest. But really when you see these grade five injuries, there's just not a lot of spleen left. It's hard to even draw the margins of the spleen, right? Because basically at this point you have these large stellate lacerations or splenic fragments as I like to think of them, where it's just kind of all this tissue is just there but it's not really organized anymore. So you're going to have areas that are devascularized. This patient also has frank vascular injury here as well. Okay. So that's kind of the most extreme example. So I did want to talk briefly about the Surratt spleen. So initially it was believed, now most of this diagnosis was going to be an angiography rather than CT scan. I can say in the previous century, because I am that old, that most things were actually done, the definitive diagnosis was all angiography. This is before CT and trauma scans were really on the forefront. And it was believed that this whirls and swirls pattern was the most specific sign for any injury when these patients went to angio. And so that's like Van Gogh's Starry Night. Well then there was a paper that came out actually in AJR in 1979 and said, actually we don't think it looks like whirls and swirls. We think it looks like a bunch of dots. So if you remember the image two slides ago where we had all those tiny pseudoandrisms, that's what they're referring to here is all these little tiny dots being multiple, multiple pseudoandrisms throughout the spleen. And so they thought it was more of a pointillistic technique of Surratt, who was actually a contemporary of Van Gogh. And I picked this particular painting because this painting actually has a hidden spleen. I don't know if any of you like Griswoldo, but there is a hidden spleen in here, right there. So he actually knew in 1888 that in the future we were going to be here today talking about splenic trauma and wanted to make sure we had nice images. So this is a case that we actually had where I think it's actually both kind of whirls and swirls and some dots as well, right? I think the key point is it doesn't really matter which artist you like better. What the point is, is that vascular injury is what is really important. And when we see these vascular injuries, this is our big, big predictor of splenic trauma. And it's going to, as we see in the subsequent slides, it's going to really drive our treatment. So images on the top here are actually arterial phase, images on the bottom are the portal venous phase. And I think you can see that there's these AV fistulas and some pseudoandrisms as well. What I really want to draw your attention to here is that the portal venous phase images are really not super impressive, right? I mean, look, you know, we always have streak artifact because arms are down, patients are severely injured. There's wires and tubes, like you're never getting really a perfect image. And so it's easy to look at this and say, gosh, it's kind of heterogeneous. I don't know, maybe if you hadn't looked at the arterial phase images, you could walk past this and that's actually what happened. So it's not only important to get the arterial and portal venous phase images, but you really need to make sure you're taking a conscious effort to really look at both of them. So this patient came back five days later because it was read as negative. And now it's pretty obvious, right? We can see all this perisplenic hemorrhage. And actually on the image over here, you can actually see there's actually a frank tear in that thin capsule and then perisplenic hemorrhage as well. So delayed splenic hemorrhage is defined as no injury on your index scan, but delayed bleeding from a splenic injury. Thankfully, it's very, very rare. Unfortunately, these patients usually have a higher morbidity and mortality and a very high rate of splenectomy because they've sort of missed their window for angiographic intervention. And in this one particular recent study, they went back and actually looked at all their cases of delayed splenic hemorrhage. And the vast majority, in this case, 72%, were actually due to suboptimal initial imaging, right? So again, if you're not doing arterial phase imaging, you're going to be missing potentially vascular injury. And if you don't have good quality portal venous phase images, which I will admit even at my institution where we scan gazillions of these a day, we often have images that are limited. And I actually put that in reports. I will say that there's substantial streak artifact through the abdominal solid organs that's limiting my sensitivity for detection of parenchymal lacerations. And if there's sufficient clinical concern for a solid organ injury, that they should consider repeat imaging. So in this case, this patient was read as negative as well, which I think, you know, going back, I really didn't see anything. But there was, again, a lot of streak artifact to the spleen. And on day four, we can see that there's a little bit of a defect here. We can actually see a perisplenic hemorrhage, a little subcalcic hematoma there. It's a little bit harder to see on day four because it's a motannuation to the surrounding spleen. And then on day seven, it becomes even more apparent. So what are our treatment options? Well, we have non-operative management, which basically is they get admitted to the ICU and observed. We have endovascular treatment, which is splenic artery embolization. And we have surgical management, which is basically a splenectomy or splenic repair. And there was actually a very large study, which was 11 level one trauma centers and 1,300 patients looking at these vascular injuries. And what's really important to note here is that splenic artery embolization increased 15.6% over the study period. If you had active splenic hemorrhage or contained vascular injury at CT, you had a higher risk or higher odds ratio, I guess I should say, of going to IR over surgery. If you needed blood products, it was more likely you were going to go to IR. And what was also interesting is that patients that had active splenic hemorrhage were much more likely to be discharged earlier, probably because they went to faster definitive management. The World Society of Emergency Surgery also came up with a consensus document with follow-up strategies for patients managed non-operatively. In these cases, they were considering non-operative to be anything that was basically not to the surgeon. So they were considering IR as non-operative management, which I think most of us consider that as also to be an operative technique. And basically, they stated that splenic artery embolization is really your first-line intervention in hemodynamically stable patients, irrespective of injury grade, to have a low threshold for patients with AAST grade 3 injuries, and that all hemodynamically stable adult patients with grade 4 or 5 injuries, even in the absence of a contrast blush, should really go to SAE. So again, really becoming the major treatment here. So in terms of splenic embolization, it's a very safe, effective procedure. It can be utilized successfully in these higher-grade injuries. And I realize that this may be a little bit institution-specific, just because not everybody has a full IR team at the ready at all times. And so some people may still transfer or whatever, or do different management just related to where they're at. There are risks of re-bleeding and infarction, as well as infection, with higher rates of abscess formation, somewhere in the 3% to 7% range. You also have your problems potentially related to contrast administration and your access site as well. And I do want to keep in mind a couple things we talked about at the very beginning. When you do get a splenectomy, you are going to need to be vaccinated for encapsulated organisms. Children often receive penicillin for two full years. And even some adult patients are going to have to go on to lifelong antibiotics and might even have associated travel restrictions. So again, splenectomy is not without its risks, in addition to all of your surgical factors as well. So really the three key learning points that I wanted to make sure that you walk out of the door today remembering is that the spleen is important, right? It has important immunological roles, and we really should try to preserve it as much as we can. Quality imaging with arterial and portal venous phase CT is really necessary to capture all your splenic injuries, particularly given that vascular injury is what's going to be driving your treatment. And splenic artery embolization is safe and effective, and it is increasingly being used as a first-line treatment, even for very high-grade injuries. And that's it. Thank you for your attention.

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