Introduction to Radiology - Basics of Xray 3
Summary
This on-demand teaching session is for medical professionals interested in learning the basics of abdominal x-ray. We will cover indications, a good quality abdominal x-ray, structures visible on the x-ray, the location of the large intestine and small intestine, normal findings, alternative views available, and the systemic approach for the Abdo x-ray. The session will help medical professionals interpret x-rays quickly and efficiently, and will also teach them how to differentiate between bowel air and pneumoperitoneum.
Learning objectives
Learning Objectives:
- Explain the role of an abdominal x-ray in comparison with CT-scans and ultrasounds.
- Identify the different structures for an optimal abdominal x-ray.
- Describe the findings of a good abdominal x-ray.
- Differentiate between large and small intestine on an abdominal x-ray.
- Explain the systematic approach in using ABDO X to assess an abdominal x-ray.
Speakers
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Computer generated transcript
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The following transcript was generated automatically from the content and has not been checked or corrected manually.
Um Welcome everyone to the third session on basics of x-ray. Uh In the 1st and 2nd 1, we talked about chest x-rays mostly. And then today we'll be talking about um abdominal x-rays. Um I'll just hand over to our P A today, our tutor today. Nothing. Um And if you just take us through this session, he's uh junior clinical fellow in software plastics um department. Yeah. Thank you. Thank you so much David for the kind words. Um So people who had previously attended the previous two sessions, they know we talked about um the chest xrays in two sessions. Today, we are going to talk about the abdominal x-rays, just the basic stuff. Um And uh we covered some basics of the chest xrays like the densities um and how you differentiate between the soft tissue, bone foreign body. So we're not going to talk about those things in this. We will just go through um abdominal x-rays basically. So, um as we all know, um ct scans and point of care, ultrasounds are readily available. So, if somebody's got right upper quadrant pain, we get the ultrasound done grading um cholecystitis or gallstones. Um and if it's more sinister pathology that you suspect with somebody who's gone with abdominal pain, diarrhea, vomiting or any gastrointestinal symptoms. So, we think of CT scan first. Um So the question is, are the abdominal x-rays still relevant? Do we need to um, go into the detail of these things? So, um during my rotation in upper G I angina surgery, um I have seen and we have done abdominal x-rays where somebody had abdominal pain. Um and we got an abdominal x-ray because the CT scan was not readily available and we wanted to get um a diagnosis quicker. Meanwhile, the CT scan was done, we got the CT scan at the end anyway. Um but we got the ABDO x-ray first. It gave us some information and to prepare ourselves. Um What was the diagnosis? And I remember it was a case of sigmoid Bulus that we could see on the um uh abdominal x-ray. And then we got the CT scan further down the line. So, um in indications, yes, for emergent evaluation. When the CT scan is not readily available, you can get um abdominal x-ray done. Um You can do this to rule out um pneumoperitoneum, which could uh come from any Vira perforation. Still, another indication is even if you do the CT scan, um abdominal x-rays are done to um localize the foreign bodies where they are, where they're going. They usually uh x-rays are the first choice when you want to know where are the um abdominal foreign bodies are. So the next indication could be just to check the um positioning of the lines and tubes and to see the devices if they are in the right place. Um So again, um NJ tubes, um we get abdominal x-rays to assess if they're in the right position. Sometimes. Um If you don't wanna give uh lots of radiation, you can get an ab um x-ray to look for the renal stones, but it is not gold standard and it is not recommended. Um And mostly renal stones are not seen um in an abdominal x-ray because of the overlying bowel. So, um what is a good quality abdominal x-ray? It should include all of the abdomen um heap from below to the um hernial orifices and it should include left to the right abdominal walls as well. So, hemidiaphragm to pubis symphysis, lateral abdominal wall in somebody who's got high BMI um you may need to get 23 x-rays to include all of these things. Uh What should be the ideal exposure again? Just like chest x-rays, you should be able to um see the um vertebral bodies clearly. So that would be an optimum um exposure of the x-ray. Um So, um as I said, if somebody has gone with abdominal trauma, we get a CT scan done. We don't get an abdominal x-rays, but there are some conditions where you can go for the x-ray as well. Right, upper quadrant pain, we go for, um, ultrasound first and then CT scan if needed. Suspected intra-abdominal collection is never, uh, we don't get any, um, abdominal x-rays done. We get a CT scan, acute upper G I bleed. We go for a CT scan or scoping the patient, um, suspected abdo malignancy. Some messages you can see, but obviously in malignancy you need more information. So you get CT and died investigations then. So which views are the uh views for the abdominal x-ray? If uh somebody has not specified, the view of the x-ray is usually standard A P Supine where the patient is holding their breath and lying down. Um If it's not mentioned, just assume the abdominal x-ray is in supine position. Um We do get um x-ray abdominal erect uh with um chest x-ray rec to rule out pneumoperitoneum or air under the diaphragm, left lateral decubitus x-ray, special eye on his side. And if you see any gas in into the loop, it's uh sometimes happens in acute pancreatitis that you can see this. So, um this is how a normal abdominal x-ray looks like you got bones in it, soft tissue, um pelvic bone and sometimes um if any devices or lines in the um abdo pelvis, you can also spot these. So just going through um where the normal structures are. So, liver is on, on your right side, just below the right hemidiaphragm. That's why you don't see any um bulbs there because liver and it's ligaments, they keep the bul down from this side, your spleen is there and it's just, um, up to b 12 rib. It rarely, um, comes down the ribs unless it's a splenomegaly. Your kidneys, your right kidney is a bit higher than the left one. Um, moving forward, your large in, um, in your colon. Um, it's like a rectangle, its, its on the periphery, um, where you get an abdominal x-ray done. The interesting bit is that the retroperitoneal structures of the colon, like ascending colon, the descending colon and the rectum, they're relatively fixed structures. Um So in an X rays, they rarely move and you can expect them um to be there. But the transverse colon um the and the sigmoid, uh these structures are relatively mobile. So in different x-rays, you will see them in different places and in different conditions also. So um expect to find them anywhere but these ascending, descending and the rectum, you can rely on them that they will be in one position. So, talking about the large intestine. So, um how do you differentiate between the large intestine and the small intestine on, on an abdominal x-ray? The, as I said, the large intestine sits on the outside and it's kind of sort of that way and the small intestine is in the mid, there are other differences that, that gives uh you can differentiate both of them on the basis of um the first is in the large intestine which are basically formed by the nui. So these are these depressions or ridges that which do not cross all of the um colon. They start and then they finish before they cross all of all through it. So these are called the rations. So if you see these, it's, it's the large intestine also, um sometimes colon contains something which is normal is fecal matter which is kind of this motile appearance. So, ascending, descending and then the rectum, you see this mortal appearance, this is normal, this is just fecal loading, small intestine. And as I said, it's kind of in the center. So you see something um we call valvular cone. So these are ridges which cross all through the length, the width of the um small intestine on the x-ray. Same. You see these crossing all bit of the um small intestine. So that's how you differentiate between the, these two small intestine in the mid with valvular convenes and large intestine. Although as I said, the transverse colon sometimes could be found in the center as well. So we were just look for the um valvular conven and what other structures are there? Sometimes you see the um SARS muscle shadow um looking at the um you've got your spine there. So your 12 rib is attached to the T 12 L1 L2 L3 L4 L5. And then you've got your sacrum if you know where your kidneys are, which are not always um seen on the abdominal xrays, you can kind of trace the tract of the ureter that it takes before it goes into the bladder. This is your si I joint, your eye, your bone, femoral head are also seen. So regarding the pelvic bone, um if you see the fractures of the pelvic bone, um so pelvic bone is like a polymer, like a polymer breaks at two spaces. So if you find fracture at one side, look for the fracture on on other side to complete the polymer fracture. So there are like three rings here. The one big ring, first, polo second, two small rings between the pubic and is your bones. Um So if you find a break here, there will be a break on the other side as well. So how do we um do a systemic approach uh for the Abdo x-ray? So there is a very cool mon it's called ABDO X. Um Basically it stands for A, for a B for bowel D for dense structures or calcifications or for organs and soft tissue, external objects and lines and tubes. So we will go through one by one by one. So A is for a um it is very hard to see an abdominal x-ray. Best choice to pick up pneumoperitoneum is um CT scan if you expect that there is a pneumoperitoneum or rupture of the visa, get a CT scan. Unless you can't get a CT scan and you won't rule out urgent basis, then you get can get an ABL x-ray. So we will go through the all of these things one by one. So air under the diaphragm is a very classical sign in old days before the CT scans. It was pretty much the um standard investigation to rule out um any visual perforation. And if you see those crescent shaped um uh under the both hemidiaphragm, it was diagnostic of um a rupture of the visa, small intestine, large intestine or stomach. So, um one thing that could look like air into the diaphragm, but it isn't um is something called tele sign. So it's a pseudo um pneumoperitoneum. Basically what happens as I said, the liver sits there and you don't see bowel there in the right hemidiaphragm. So what happens is sometimes the bulbs are there and you see the air in the bowel making um air into the diaphragm, kind of figure how you can be sure that this is not the ruptured viscus air, but it's just from the um bowel loops is you see for these rations. So when you see these stresses, you, you know that this is the bowels and this is the air in, in the, in the bowel rather than air under the diaphragm. So next, um uh the other signs especially in, so the air into the diaphragm is when you get an erect, excuse me um erect abdo x-ray. Um What if, um, somebody had an x-ray as in spine position? Can you rule out if there's any air in there? Uh Yes, you can. Um, first I'm gonna talk about the regular sign when the air is spread out in the abdominal cavity. What happens is that the bowel loops, they become prominent. Usually you can't see the bowel loop margins or outline this mouth or this crisp. Uh, but when there is air outside, what happens is that there is air inside the bowel and there's air outside the bowel. So there becomes an interface between air inside, air outside and the bowel wall. So you get these crisp bowel walls, which actually called um, regular sign. And it also tells that there is air inside the abdomen and probably there's a ruptured viscus. Sometimes you see these triangle shaped, um, signs as well, which are very hard to see. Probably a radiologist can. And, uh, and when you started, when you start to, um, examine the Abdo, um x-rays, it's very hard to look for these things. Um, these are called telltale triangles and it's also made by um, the air in the, um, Meoni and, and they come in various triangle shapes. So imagine, um, somebody has got a bowel obstruction and after the bowel obstruction, um, the pressure on the wall is extreme and after that pressure, the necrosis happens. And after the necrosis, what happens, the bowel wall gets there are some gasses produced in there, then it gets weak and then it just ruptures. So, um, in here you see the regular sign, the crisp outline boundaries of the, um, bulbs. And if you focus here and here and here, so the crisp lines you can see. Yes, but it's a bit thicker than the, these crisp lines. So these are a bit thick as compared to the, um, these lines. So the reason these are thick because there is no air in the wall of the lumen of the bowel, which has come from the necrosis. So this thickened bit also tells you, ok. Um There is necrosis going on, probably weak abdominal walls. Sometimes. Um you can see the air inside the bili tree when you see the air inside the military. Usually, it also has um I BS picture um of the small bowel. Um So it's, it, it, it's, it's better mnemonic in the um the gallstone ele very much like um tension, uh pneumo Rx. You can get something called tension, pneuma abdomen. You had a, the biopsy taken or because of an injury, a condition develops where there's just one way all the air goes in but doesn't get out, you see air all in the abdomen. So when you see this, all air in the abdomen, all the abdominal vis vis, they, they are, they're compact in, in the center and getting um pressure from all this side. This probably needs surgery and fixing of the issue going forward. Um, how do you decide? Ok. Um, this bowel is thickened or this bowel is dilated and this is not, um, what are the normal, um, sizes of the bowels? So there is a 369 rule, um, which gives you an idea. Ok, this bowel is dilated and this is not so small bowel, um, if greater, if it should be less than three centimeters, if it's greater than three centimeters and it's dilated, large bowel should be less than six centimeters. Appendix less than six millimeters. And, um, because of its sebaceous capacity, um, it's nine centimeter up to nine centimeter cu is considered normal. So, um, if these small bowel greater than three centimeters large, greater than six and second, greater than nine and appendix greater than six millimeters, then these are dilated. So, in here you see the, um, venta going all width of the, um, bowel and you see it's more than three centimeters. So, you know, the small bowel is dilated. Then you see here, um, this is the large bo, as I said, don't be confused that the, we know and from a anatomy books, you will remember that the, they teach us that colon sits like a rectangle on the outside, but transverse colons and sigmoid colon, they move really anywhere and especially in pathology and they're out of place. Um So in this large bowel obstruction, the key thing is the Hatra they don't run all bit of the um, of the bowel. So that's how, you know, OK, this is the large bowel which is dilated air fluid levels. Um So in, in right lower quadrant 35 air fluid levels, which are less than two point centimeters, normal, um, greater than two air fluid levels. Um, in dilated small bowel caliber, I would say more than three centimeters abnormal. So this 2.5 centimeter caliber is for the air level does not. Um So basically a fluid level does not help you distinguish if it's a small bowel obstruction or is it just I um so their significance is kind of overrated. What are the causes of air fluid levels? Um small bowel obstruction, large bowel obstruction, paralytic, ileus gastroenteritis. You can see that in hypokalemia, uremia, just diverticulosis, mesenteric, thrombosis peritoneal mats and if somebody had cleansing enema. So next we're going to talk about the VV. So vus is when um uh the large intestine just falls on its m entry and cuts off its um caliber. So you see both um sigmoid and transverse colon ulus in this um picture. Um So this one is uh sigmoid will be less where you see the sigmoid will be less is just have become so much large and it, you don't see any sra there as well because of the enlargement and the size of it and it essentially looks like um a coffee bean. So this is called a coffee bean sign. It has, um, twist it on its mid entry or right about there and just block it just behind it. So this is um, a surgical emergency. Basically, it needs a, um, um, sigmoidoscopy urgently or a surgery. If it hasn't perforated, if it's, uh, not perforated, you could go for, um, sigmoidoscopy and try to relieve this. But if it's perforated then you need to go and do hir me. So cu um sometimes cecum does the same thing um turns over and then the the wall is incompetent, then you get this um all the depression builds up and everything builds up behind it as well and you see these di direct ball lobes. So basically, it looks like an inverted C, it doesn't look like that classic um coffee bean sign, but it looks like kind of an emergency. And you know that because that's um maybe less. Next thing um I want you to know about is the thumb printing sign um and just differentials. So basically most of the um inflammatory and infectious um conditions give you this kind of appearance. So if this is the normal um colon and you get your s which don't run all the way but and before they go towards the midline, so your hostess um if this is normal, so it's like kind of somebody has put their thumbs over there. So these light gray areas. So if you see this, think of um these differentials IBD, um either ulcerative colitis or Crohn's infection, um membranous colitis, um po ischemic divertic colitis and hemorrhoid lymphoma, myeloid Paphitis. You can see in all of these. So if um a um if the colon has been um through a chronic colitis, it could lose its um rations and just look this kind of smooth, which is basically called a lead pipe sign. So, and the next we're gonna talk about is the um D is the dense structures um or calcifications. So this is your um 12th vertebra with the 12th trip coming out of it. After that, you got your L1 L2, L3, L4 L5. So basically, um look for any compression fractures or max in the pedicles of the these vertebras or any, if there are any previous um surgeries, you may find that implants that as well your ileum, your si joint, if in a, in a fracture or in a trauma, these si joint could be um wide. So look bilaterally, you can see your sacrum there and the femoral heads as well. So, uh in terms of calcifications um in this x-ray, you basically see um gallstones calcified in there, which is probably an incidental finding here because as we know, we don't do abdominal x-rays to look for gallstones, we do the ultrasound scan because it's easier cheap and um no radiation at all. What are the calcifications you can see again sometimes incidentally, you can see, I want you to know about these, um, these things because you don't probably do the abdominal x-ray for these things. Uh, but when you look at these, um, you know, ok, it's, I know what this is and it's not something which you have never seen before and you don't make wrong diagnosis based on that. So, postal gallbladder, a calcified gallbladder, um, looks like this on an abdominal x-ray. So this is in the left kidney. Um This is a stag horn called calculi. Again, we do um low dose CTK to rule out renal calculi. We don't do um abdominal x-rays generally. So um sometimes um you do see the renal stones. So twe um 12th vertebrae, L1, L2, L3 and on the level of the L3, you see a small stone there. So as we know the right kidney sits about there and then they, we, we knew the ureter kind of follows its tract like this and then goes into the bladder. So this is probably in the ureter, a small stone in there. Pancreatic um calcification in chronic pancreatitis, you can sometimes see the calcifications in the pancreas. Sometimes you see the adrenal calcifications sitting on top of the kidneys. Sometimes um you see aortic calcifications with the um aortic aneurysm. Sometimes the mesenteric lymph nodes are calcified. So this is basically um calcified fibrosis, fibroid, sorry, sometimes you see calcified prostate. The next we're gonna talk about is um organ evaluation. So again, the x-rays diagnostic capability is very limited for the organ evaluation. But sometimes on a on an x-ray, you see something obvious like um this spleen. Uh it's, it's a splenomegaly and uh the spleen is really bad. You see in this, the the liver is, is enlarged and and this patient has got her omy. Sometimes you can see the masses um in abdominal um x-ray, you see the right renal mass which has distorted the shape of the kidney. Next, we're gonna talk about um the lines and tubes. So the obvious one, everybody knows this is an ID, your property which is rightly placed in the uterus there. This is um ring pessary, the batteries that they use. Um So these are the um tubal ligation clips similarly. Um there is no x-ray in this presentation for but somebody who has had cholecystectomy, you will see smaller um clips from the cholecystectomy in the right quadrant region as well. So what are these dots? These dots are from the hernia mesh repair. Um Don't confuse them for any foreign body or things like that. And as I said, sometimes um the these um x-rays are used to um assess if a tubes, reginal tube is in the right place, especially if you work in an upper G I department. So you've come across to verify these things. So basically, it goes through the um gastroesophageal junction. So you've got your stomach there, then it just crosses the pylorus, then it goes through the jejunum part is the c shape of the duodenum and then it goes into the jejunum. So this is in the proximal part of the jejunum. But um this is probably adequately sitting the, a bit further down the line. There are um many, many other um devices and lines and, and things, for example, some people have got an electronic devices placed in there uh for the um for the spine, for the spinal cord, sometimes for the gastric uh purposes. Um There are other lines as well and, but I haven't included all of these in this because it becomes a very, very lengthy um list of things. Um but these are, I think the basic ones that you see and I think you should know about um any questions. Can, can everyone hear me? Can you guys hear me? Yeah, I can hear you. Ok, fine. Yeah. Um Thank you for the session. Um When I was even putting it out there. Um One question I was putting forward was uh x-rays even still useful in clinical practice um these days. So I I think it's, it's for a lot of people to still see like even though it's used have become quite limited with the availability of CTS. There are still some reasons why you may not want to go directly to P CT and still do an abdominal x-ray and it's important to still be able to recognize these things, the basic principles of recognizing them. And I think you actually took this session directly from like that, that approach which, um, I found very, um useful, um, just letting us know, you know, what to expect in clinical practice. Um, what to like knowing that you don't routinely order an abdominal x-ray for this. For instance, I mean, stones in the gallbladder, you won't order an abdominal x-ray for that. It's an ultrasound so that people will know exactly like when you order different investigations. Um, but the abdominal x-rays can still, um, be useful sometimes, um, when you can do ac T, so thank you for, um, taking it from that angle and actually explaining it properly from there. Exactly. Um, I agree there, there was a time when the CTS were not very common or there were no CTS at all and we had just the abdominal x-ray and um, we relied for the radiological assessment of the abdomen just on the abdominal x-ray and there are many, many other signs as well, um, which you still go for or can go for. But as I said, the CT has replaced those things like in trauma. We don't, um, get an abdominal x-ray. There is an abdominal x-ray and a pet scan as well, uh, which gives you some idea. But, um, when you can get a CT scan and when CT scan can give you more information we don't, I agree, tend to um order the abdominal x-ray, but you will see in ideal, um it's not an ideal world and sometimes in hospitals, um you can get an x-ray readily and a CT scan you can't um because of the, how busy it is. Like I um we had, I mentioned um a patient where we got an ABDO x-ray which showed a be and we were able to organize um A P um although it didn't work out, but we knew what the diagnosis was before we could get CT scan done and still in some conditions. Um We do get the um abdominal x-ray done like uh to check the position of the NJ tube if you don't do a CT scan to check that position. So um yeah. Um Do we have questions from our um attendee? Any questions I can check the chart box if there's any, no, there, there isn't any if anyone wants to talk directly, I could invite you to this stage also. Just let me know. Yeah, sorry. I, you were saying something. So, meanwhile, um just to summarize things um when you're looking at the abdominal x-ray, just have a look if it's uh it covers all of the abdomen. Um hemidiaphragm did the orifices and the both elect walls. Um then go through this Abdo approach basically, which is to look for air. Um I I, if I'm looking at the app to x-ray, that's the first thing I will do, I will look for air, especially air under the diaphragm. If it's a, er, direct x-ray, if it's a spine x-ray, I will look for the regular sign, decreased boundaries of the, um, intestines. And I will look for those triangles which are very hard to see if it's an direct x-ray. I will look for, um, air into the diaphragm. Then I will make sure that this is not, um Caity sign that those um crescent shaped um it's not associated because the bowel is sitting up and it's generally um a perforation viscus. So um those are the main things I will look for the air. The other things like pneum mobilia or the air within the walls of the um intestine is something small. Um Then next, I will look at the bowel, I will look um where the bowel exactly is if, if the large intestine is in the right place, as we know the transverse colon sigmoid can move, then look at the um caliber of the things. Do you see any air fluid levels? Um Do you see any um uh coffee bean sign if it's enlarged? Do you see a revered C sign for the scal Bulus? Um Then you look for next, any calcifications, obviously, you can see and then look for any organs that you can see and appreciate. And if, although the organs are really hard to see on, on abdominal x-ray, um especially if you're big neck. But if you can see an organ, just assess if it's a big enlarged or not, then look for the um external objects, line and tube and then correlate with patient's history, um what they had done. And for example, if you see some clips and you don't know, OK, I see it's in that position. It could be something like that go through the past medical history and you will know this patient had done this operation done. And probably these are the clips from that or if you're asked to confirm the position of the int you, then you probably can. So you don't miss out on something major um and can formulate your differential diagnosis just on this very basic knowledge of the abdominal x-ray as well. Thank you for the um summary. That was a good um summary with the acronym that you gave. Um Just to remind everyone that um I'm sharing the feedback forms. Um Your feedback is actually very um important both to us as the organization and to our speaker. So please try to fill um the feedback forms and you get the certificate for attendance um of this session. Um If no one has, I think I'm just, thank you, I can see on the chart book. So if no one has um question, I think we can um close, we can close you very much for taking us on also very direct. And so to one thank you so much for having me, David again and see you guys soon. All right, thanks. Cheers. Bye bye.