So, this is a topic that is kind of near and dear to my heart. If you were to talk with members of my team, they know that whenever we see a new patient, I expect that they'll have all the relevant imaging studies pulled up and ready to go to take a look at. And I think that none of us have formal training in radiology, but we can all become quite proficient at it by pulling up the images whenever we see a new patient. And the thing to keep in mind is that, unlike the radiologists who oftentimes don't even see the patient, we know the patient best. We've done the initial evaluation, we've ordered the appropriate imaging study, and there's no question that we're the best people to be looking at these images. And as Jill pointed out during her talk yesterday, oftentimes you can get increased reimbursement by getting a better coding charge by noting that you made primary review of any appropriate imaging studies. So what we're going to go over today is just kind of some of the general tests, imaging studies that are used in GI. And then I'm going to kind of go through just like a little show and tell to highlight some of the common images or common findings that you would be looking for whenever you see one of these patients. So again, we'll review some of the common GI imaging studies, review some of the clinical scenarios in which imaging can really make a big difference in terms of management. And then the majority of this discussion will be to go over some of the specific examples. So obviously there are a lot of different imaging studies that can be ordered. It can be a bit overwhelming knowing which is the most appropriate test for a given clinical situation. But some of the more common areas that we'll order tests would be things like ultrasound to evaluate, especially the gallbladder and the pancreas, mesenteric Doppler studies. Plane X-rays still do have a role in a lot of areas of GI, including video swallow and various contrast studies involving the rest of the GI tract. Obviously cross-sectional imaging with CT and MRI are a big part of what we do. Those are often the studies that kind of take the most practice to become proficient at reading. We'll go over some of the nuclear studies, or as one of my attendings used to tell us, unclear studies, unclear medicine, but there are actually some pretty useful applications for nuclear studies. And then of course, some of the procedures that we perform require interpretation of imaging during the procedure itself. So some of the clinical scenarios in which imaging can really be useful include things like dysphagia, abdominal pain, epigastric and right lower quadrant pain specifically. The patient who presents with jaundice is almost always evaluated with some type of an imaging study, suspected bile leaks, obscure GI bleeding, and liver lesions. Obviously endoscopy plays a very important role, but the imaging studies are really complementary to a lot of the different types of endoscopic procedures that we can offer for these patients. So for the rest of the time, we're just going to highlight some of these, I'm going to highlight some of these specific clinical scenarios, and then again, show you some interesting images that can kind of reinforce some of these ideas. So the patient who presents with dysphagia is a challenging evaluation, and typically the first thing we're trying to sort out is whether we're dealing with oropharyngeal dysphagia, whether there's a defect in the swallowing mechanism, or whether we're dealing with esophageal type dysphagia. The majority of patients with esophageal dysphagia will proceed to endoscopy, but if your initial suspicion is that you've got a patient that may have oropharyngeal dysphagia, then we're typically going to be starting with a video swallow. And here's a nice example of what a still frame from a patient with abnormal swallowing would show, and you can see there's contrast that goes down two different pathways. It enters into the esophagus, but it also enters in anteriorly into the airway, into the trachea. And this would be a pretty classic finding for somebody who's having aspiration and would need an additional evaluation to determine the reason for the oropharyngeal dysphagia. Another very useful imaging study in dysphagia is the patient with suspected Zanker's diverticulum. In fact, this is the best way to make a diagnosis of a Zanker's diverticulum. Zanker's occur when there is basically an outpouching or a diverticulum that forms just above the upper esophageal sphincter. That can be very easily visualized, usually on lateral imaging, and you can see this is a classic image of contrast going down and filling this sac, this diverticulum where food and oral secretions can easily accumulate and lead to certain problems. So if you have a patient with a suspected Zanker's diverticulum, oftentimes this is the best test to order next. The one type of esophageal dysphagia, which can be evaluated fairly well, at least initially, is the patient with suspected achalasia. So if you had a patient that has dysphagia for both liquids and solids, but you're pretty sure that it's coming from the esophagus, a barium study can be helpful. And this is kind of a classic imaging study where you see a large dilated esophagus and then tapering down to what we call a bird's beak. You have to use your imagination, but at the very lower part there, you can see that it does taper down to this very narrow area. And this would be a classic imaging finding for a patient with achalasia. Of course, we typically would then follow this with an esophageal manometry test to confirm that achalasia is present. But again, the imaging study here can be helpful to get you headed in the right direction. Another area, another symptom, which can be oftentimes evaluated with imaging studies is epigastric pain, especially if the endoscopy does not identify an explanation for the patient's epigastric pain. Usually the next test to consider would be to order an ultrasound. Ultrasound is very, very accurate for diagnosing gallbladder problems. The sensitivity for gallstones is at least 95%. And in this case, you can see on the left panel there, there's an arrow pointing to a large stone. Stones can be differentiated from polyps by the fact that they're bright on the surface and they have what's called posterior acoustic imaging. That occurs because the ultrasound waves are being reflected effectively by the stone and it's effectively casting a shadow beyond it. And so both of these panels show stones, the one on the left, one large stone, the one on the right has multiple small stones. And of course, somebody with this presentation and this finding would oftentimes be best served to see a surgeon to consider a cholecystectomy. Cross-sectional imaging, abdominal CT, this is the one that probably takes a little bit more work. But again, especially if you have the radiologist's interpretation available, and they often do nice things like put arrows or circle things that are of note, it can be very useful to identify problems. So one area where it can be helpful is a patient with epigastric pain, an abdominal CT is oftentimes for patients who have complicated pancreatitis, or if they present with abdominal pain, but the lipase isn't significantly elevated, you can look for changes suggestive of pancreatitis. And in this case, you can see in the top image there, there's a kind of a large fluid collection. The bottom image shows fluid collection as well as quite a bit of edema surrounding the area of the pancreas. This is a little bit more of an obscure case, you won't see this too often, but it's such an interesting imaging study that I thought it'd be worth adding. The patient presents with usually epigastric pain as well as vomiting, who has developed a gastric volvulus. And in the case on the left, you can see there's an arrow pointing right where the volvulus has formed, the stomach has kind of twisted on itself. And then the image on the right, which is kind of a different way to reconstruct the CT images. The A is showing where the antrum is, the F is showing where the fundus is, and obviously those are not in their normal orientation, the antrum has flipped up above the fundus. And this diagnosis is something that needs to be managed very quickly, because these patients can develop gastric ischemia or even gastric infarction, where the stomach is dead. So this is an important diagnosis to be able to make, and CT really does offer a good way to make that diagnosis. Getting back to the problems with the pancreas, if you have a patient who you suspect has chronic pancreatitis, let's say they present with epigastric pain, maybe they've got some weight loss and some steatorrhea or fat in the stool, one of the classic findings that really confirms a diagnosis of chronic pancreatitis is the presence of calcifications within the pancreas. And you can see where the arrow is pointing at those bright white areas, those are essentially calcium deposits within a very atrophic appearing pancreas, and this really does confirm a diagnosis of chronic pancreatitis. For patients with epigastric pain, especially if they give a history of postprandial abdominal pain with weight loss, maybe they're afraid to even eat because of the pain, a Doppler ultrasound of the mesenteric vessels can be very helpful to look for evidence of chronic mesenteric ischemia. And typically, you're able to image the superior mesenteric artery as well as the celiac artery and look for changes in flow. These patients often have very high flow through stenotic areas within the blood vessels, and this would be a patient who would potentially then go on to either a CT angiography or perhaps even an angiogram performed by a radiologist. Another area symptom which is particularly amenable to imaging is the patient who presents with right lower quadrant abdominal pain. For the patient with acute appendicitis, this is really kind of the best imaging study for making a diagnosis. And so you can see in these two images, there's, again, the radiologist has kindly put a nice arrow in place so that we can see what we're looking at, but on the left, the arrow points towards a dilated edematous appendix, and the image on the right shows an inflammatory collection around the appendix itself. So while we may not get called as often as the surgeon would to see somebody with acute appendicitis, it's still useful to know what that imaging study would look like. A little bit, another kind of more obscure diagnosis, but this is a very satisfying diagnosis if you can make it, is the patient who comes in with intermittent right lower quadrant abdominal pain. Perhaps you've done a colonoscopy and looked at the terminal ileum and don't see any obvious abnormalities. If you happen to perform the CT scan during an episode and can identify intestinal angioedema, it's pretty obvious on the left side there, you can see that one of those loops of bowel is very, very swollen and edematous. And again, this can be a challenging diagnosis to make because the symptoms can be intermittent, but the CT finding can really confirm the diagnosis. We do rely on CT imaging to help make a diagnosis of Crohn's disease, and oftentimes you'll see pretty pronounced thickening within the terminal ileum, and in the case of this patient, there's a very thickened loop of ileum, which although can be seen in other conditions such as lymphoma or other malignancy, the presence of thickening in that area with the right type of symptoms would be very suggestive of somebody with Crohn's disease. Imaging studies are really essential for working up the patient with jaundice, and typically the first question that we're trying to identify is, is this obstructive jaundice or is this some type of a hepatocellular disorder or intra-hepatic cholestasis. Ultrasound is a very useful initial test for the patient with jaundice and for a number of reasons. As we talked about earlier, you can identify gallstones if present, but you can also get a very good assessment of whether the bile ducts are dilated. And the presence of dilated bile ducts in a jaundice patient really tells you that you're dealing with an obstructive jaundice problem, and then your only objective after that is to identify what the actual obstruction is. In this case here, again, there's an arrow pointing towards a stone that's causing a localized obstruction, and you can see that the ducts upstream from that stone are dilated. So this would kind of confirm that you're dealing with a case of obstructive jaundice. Abdominal CT is commonly ordered in the patient with obstructive jaundice, especially if they come into the emergency department. This seems to be the test that gets ordered first a lot of the time. You can identify things such as biliary obstruction, and you may be even able to identify the specific cause of obstruction. So in this case here, you can see there's an arrow pointing towards a pancreatic mass, and within the pancreas there is a dilated bile duct. The gallbladder is also quite dilated in this case, presumably related to prolonged obstruction of the biliary system. MRCP, as I talked about during the ERCP talk yesterday, has largely replaced diagnostic ERCP. MRCP has the advantage of being able to give very detailed images of the biliary tree to identify what the cause of the obstruction is. It can identify stones. In this case, what you can see is there are three stones that are just kind of stacked up within the bile duct itself. Oftentimes the images are essentially as good as what we obtained from doing an ERCP. It's also particularly helpful for somebody who has a malignant obstruction. So if there's either a pancreatic cancer-causing obstruction or a tumor up higher in the bile duct that's obstructing, it can be very useful to have that information before you do an ERCP because it gives you a bit of a kind of a roadmap as to what you're going to expect when you go in and do the procedure. So a lot of MRCPs get ordered for patients with obstructive jaundice. I won't belabor this too much because we talked about it yesterday, but ERCP does require interpretation of images. That is typically done by the endoscopist at the time of the procedure. The radiologist may look at it afterwards, but we usually can identify pretty clearly what we're dealing with. Again, it can identify stones. In this case, it is identifying a pancreatic cancer with malignant obstruction. The bile duct in this case is very dilated, and at the bottom there's what appears to be kind of like an apple core lesion, which is due to the pancreatic cancer causing malignant obstruction of the common bile duct. Bile leaks can be a challenge to diagnose. Oftentimes, these patients come in after, within a few days of undergoing cholecystectomy with abdominal pain. Many of them look quite ill, and there's always concern that there's something serious going on in these patients. The abdominal CT, it does not confirm that there's a bile leak, but it can identify fluid. If you have a patient, especially you know that they didn't have any ascites or fluid around the liver before their surgery, and then they show up, and all of a sudden they've got a lot of fluid that has accumulated around the liver, that can be very suggestive of a bile leak. Typically, what we will then do is send the patient for a HIDA scan, also known as polycentigraphy. Essentially, the way that a HIDA scan is performed, I think it's worth understanding because if you understand how the test is performed, you can really get a good idea for what it's useful for. The way that a HIDA scan is performed is that patients are given technetium-99 labeled immunodiacetic acid, which is injected into the vein. That is then actively taken up into the liver and then is secreted into bile, and then images are taken over about 60 minutes. The best way that I always tell my nurse practitioners to remember how this goes is that the tracer goes wherever bile flows. If the tracer initially opacifies the liver, as it gets excreted into the biliary system, it will track wherever bile flows. For example, if you have a patient that has a bile leak, the bile goes someplace that it's not normally supposed to go. Typically, as is the case here, there's a couple little arrows, especially the one on the bottom right, which is pointing towards accumulation of contrast outside of the biliary system. This would be diagnostic of a bile leak. I should point out that HIDA scans are oftentimes ordered for reasons that are probably not very helpful. They're clearly useful for patients that have a suspected bile leak. They're also useful for patients with suspected acute cholecystitis where the other imaging studies haven't been able to confirm it. The one time when I would be very cautious about ordering a HIDA scan, in fact, I would probably just not order it, is somebody with chronic abdominal pain. You end up typically getting a study that seems to muddy the water and confuse things. It really doesn't lead to meaningful changes that will lead you to make a better decision for the patient. I think the two really good reasons are for a bile leak and for acute appendicitis. Anything beyond that is probably not that helpful. Again, continuing on with the patient with a suspected bile leak, if the HIDA scan is positive or, for example, if the patient still has a drain in place and there's just frank bile coming out, then typically we will proceed to an ERCP, not just to identify the bile leak, but also to appropriately manage. These are two really nice studies of an ERCP. You can see there's bile in the contrast in the biliary tree, but then the arrows are pointing towards contrast that is leaking out into areas that it shouldn't be. Then at the same time as identifying the bile leak, we can place a stent as usually the treatment of choice. These bile leaks are usually fairly small and will close rapidly on their own. Occasionally, we'll have a patient who presents with bleeding where endoscopic evaluation does not give us a diagnosis. We are not able to identify it. This is oftentimes seen in patients with either small bowel bleeding or occasionally the diverticular bleed where even if you did a colonoscopy, all you would see is a lot of blood and wouldn't be able to identify the specific bleeding source. In the past, the first choice was typically a nuclear bleeding scan. This was performed, again, I'll review the protocol because I think it helps to understand exactly how the test can be used. Red blood cells are taken from the patient and labeled again with a radio tracer, usually Technetium 99, and then are injected back into the patient. Again, a scanner, gamma nuclear scanner is used over about 60 minutes. What the radiologist is looking for is to see if there's accumulation of tracer in any area that it's not supposed to be. Normally, you'd expect to see it in the lighting up the blood vessels in the liver and the spleen, but as in this case where the arrows are pointing, you start to see tracer accumulating outside of the vascular areas. That really points towards the likelihood of there being a bleeding source there. That has largely been replaced by CT angiography. In fact, if you have a patient who comes into the emergency department and you're concerned about, for example, a diverticular bleed, oftentimes the most appropriate initial test would be to perform a CT angiogram looking for extravasation of contrast into the lumen. Again, in this one, you can see the arrow pointing towards contrast, which is filling part of the colon. This would be a very classic finding for somebody with a diverticular bleed. For patients who have active bleeding at that time, they'll oftentimes then proceed to radiology to see if the interventional radiologist is able to embolize the bleeding source. They rely on the CT to guide them to the area where the bleeding is most likely to be. Finally, liver lesions are especially amenable to imaging studies. Liver ultrasound oftentimes is the first test. In patients with cirrhosis, it's usually the preferred surveillance test for HCC. In this case, you can see there's a hypodense lesion that's been measured there at 4.3 centimeters. In a cirrhotic patient, this would be very, very concerning for the development of hepatocellular carcinoma. Triple phase liver CT is probably one of the most useful imaging studies of the liver. This is performed by giving the patient IV contrast and then performing imaging at several different times corresponding to different phases as the contrast moves around the liver. It's very useful for diagnosing hepatic hemangioma. Hepatic hemangioma is the most common benign liver lesion that's identified usually incidentally. If you perform a triple phase liver CT, it follows this classic pattern where in the top left panel, it appears very kind of dull. It has a hypodense appearance. Then as you take progressive imaging, it fills in usually from the outside. The top right panel, you start to see some of the contrast. Bottom left, you see more of the contrast. Then by the time you take the final image, it's almost completely filled in to the point where there's not much that can be seen. This is a real classic finding. It's very reassuring to know that it's a hemangioma and not something that's potentially more serious. Contrast-enhanced MRI is also useful. In this case, this is a classic finding in somebody with what's called focal nodular hyperplasia. It has the central scar where you can see the arrow pointing towards there. Again, this would pretty much confirm the correct diagnosis. In conclusion, imaging studies really play a key role in the diagnosis and management of many GI conditions. Again, I would encourage you to primarily review all of your imaging studies. Call the radiologist if you have questions. They're usually very happy to review the relevant findings. It does play a complementary role to endoscopy. I should note the diseases of the liver and biliary tree are especially well-suited to diagnosis with these various imaging studies. Imaging studies can impact management of which of the following? Dysphagia, jaundice, obscure GI bleeding, suspected bile leaf, or all of the above. That's great. Right on. All of those are very good indications for performing imaging studies. And the second question here. Which of the following is the most appropriate initial test for suspected cholelithiasis? It's a little different from the question I asked yesterday. Abdominal CT, ERCP, MRCP, and transverse colonoscopy. Abdominal CT, ERCP, MRCP, and transabdominal ultrasound. And cholelithiasis is the presence of stones within the gallbladder. Okay, so ultrasound is the correct answer here. I guess I should clarify the difference between this and for those of you who were listening yesterday. The question yesterday was which was most useful for choledocolithiasis, and that would be MRCP because of its sensitivity. If you're just looking for gallstones, if you just want to look at the gallbladder itself, then transabdominal ultrasound is the most appropriate initial test. And final question. How to scan is most useful in the evaluation of which of the following conditions? Post cholecystectomy, bile leak, chronic abdominal pain, ascending cholangitis, or acute pancreatitis. All right, I'm glad to see it to you. I'll recognize that it's a very useful test for bile leak. And with that, I'll conclude and pass the floor back to Jill.

imaging studies

gastrointestinal conditions

radiology

ultrasound

endoscopy

diagnosis