Computer generated transcript

Warning!
The following transcript was generated automatically from the content and has not been checked or corrected manually.

So hello and welcome to my teaching session on ct heads um right, so just a couple of quick rules and disclaimers um Please turn off your camera and microphone. Um If you do want to ask any questions just put them in the chat function and we will get to them at the end of the zoom meeting will be recorded um and if you fill out the feedback forms, you get all the slides right, so before talking about ct heads, we first need to understand basic brain anatomy, which is unfortunate because it means we need to talk about the basal ganglia. It um so I always like to start off with the thalamus, so I like to think of the thalamus itself as a relay station uh In the brain, um it basically carries a great deal of information from the cerebral cortex is um but first that information has to stop at the thalamus before going going into its final destination. Uh You also have the internal capsule, which is along both sides here and you can always see this in a ct scan because it's always slightly more black than the areas around it. Um The internal capsule itself basically allows communication between areas of the, through the cortex and areas of the brain stone um Now because you have an internal capsule, you also have an external capsule almost creating a semicircular like shape here and just going all the way around and almost joining with the internal capital bilaterally. Um The external capsule is effectively a layer of white matter fibers um in the cns, uh it consists primarily of lipid and fatty tissues, which is why it can often be seen as hypodense in comparison to the rest of the rest of the areas, um it basically serves as a route for co, magic fibers from uh from the basil four grain um and effectively connects that to the cerebral cortex. It also joins the internal capsule around the lentiform nucleus, yeah so, the land reform nucleus itself is basically comprised of the footman, the globus pleaders and um all the rest of the basal ganglia um as part of the basal ganglia, it basically carries out complex functions relating to your movement, your cognition in your emotion, which is why if you sometimes have a plot or a brain bleed that wipes out the lentiform nucleus. You have problems with movement, cognition, and emotion um and then of course the easiest thing to spot on the ct scan mostly is the lateral ventricles and front the frontal horns of the ventricles as well here and here um that basically holds the csf in some ct scans. You might see a small hyper dental lesion right here uh That is sometimes the choroid play um plexus right so moving swiftly on, if I can exit out of it, moving swiftly on. The other things to know are just you're very simple brain anatomy, so your frontal lobes know the basal nuclei and the related structures, Just know where they are basically, you have your temporal lobe here your parietal lobe and then of course your except or no just vaguely know where these are in a ct in order to actually start thinking about it, so before going straight into cts, often in your skis, you'll just get a ct handed to you, but it's always important to actually kind of know why in clinical practice, you have you have reasons for a ct scan up um and in order to actually fully understand why we don't ct head everyone um It's effectively because one in 2000 CTS needs fatal cancer uh Specifically when you when you decide to cvs on under the age of 16, that actually falls about one in 1000 so the risks sometimes far outweigh the odds especially in the younger um Also pregnancy we tend to avoid uh pediatric guidelines, is very very specific which we will go through now, um but nice basically says that we need to, we need to give a cT within one hour and anyone presenting with g. C. S. Less than 13 on initial assessment. In the e. D. G. Cs under 15 at two hours, a suspected open or depressed skull fracture, so you can sometimes you'll see brain matters. Sometimes you won't you'll just see bits of skull that's to get as well. When you want to uh worry any signs of basil skull fractures. When a battle sign around the note under the eyes, or anything like that you you again start to worry a post traumatic seizure. The thing to be very careful about in e. D. Setting is sometimes people will describe post uh seizures after a post traumatic event um and the big the big thing about that is um when people have a vasovagal you will also get limb movement, so it's always important before straightaway going for a. C. G. Head to actually check their lap take to make sure that it is slightly raised, cause that's one way of confirming a seizure, um also focal your neurological deficits or any weakness in the limbs, any tingling anything like that um and we've also now changed it from one episode, 23 episodes of vomiting and it's three discreet episodes so one thing that will come up in exams or is important in this city station or rosky station for that manner, when you're asking things about vomiting, the good thing is to always ask how many separate vomits they've had um It's generally debated in the the what a distinct episode of vomiting actually is um the key thing in itself being um within 10 to 15 minutes between a vomit is counter two discrete episode of vomiting, so always be sure to generally ask about that um more ct uh indications um uh anyone on warfarin needs to have a ct head within eight hours even if there's a very low likelihood that they have done everything you still need you still need to see t them just due to the small chance that it might happen uh and you might get a brain bleed there, um bleeding or clotting disorders. Um Anyone with von Willebrand's disease generally see to them immediately um and if they have retrograde amnesia immediately before the head injury. Again, you start to panic and CTS in kids um Again, immediately in all of those, I'm not gonna read them all out, but the, the other thing here is with greater than one of um this section here. If they have more than two of them, so say they have a loss of consciousness for more than five minutes and they have abnormal drowsiness as per what their mom says that's great, but it still is a relative term so what we normally tend to do is we observe them for four hours and if there's more vaunting or there's more droughts in this or their g. C. S decreases, then you ct them again just due to the risk of just everything in kids uh specifically cancer. Um. Then finally let's just talk quickly about bruising lacerations, uh. If there is significant um swelling and lacerations, you would automatically just do a ct, just because kids tend not to bruises easily. Um Finally, n, a, i, in nonaccidental injuries that's a whole separate ball game, you've got to be really careful about them um but normally when you do suspect a nonaccidental injury, talk to one of your seniors, seniors and you will do a 20 to film regular or um stability of survey to confirm or deny any of your queries right, so uh First s be a um what is the pathology it's seen on this ct, can we launch the poem or I might be able to do it there, we go cool. Uh So the majority of you answered um d, um and we will just talk through quickly why um for di, ai, you still have a bit of great white matter differentiation there, and there it is completely normal uh string beads sign which a couple of people aren't said uh that is actually present in the abdomen. Um So just be careful on that, so let's just quickly talk through how you actually interpret a ct head before you do anything you need to check you in the right patient and the right day. The next thing you need to work out or you need you can ask why the ct head has been performed um and then is the image sufficient, so can you see. For example, in this can you see the entire pranee um are there any bits chopped off, is there anything wrong with the actual image is it blurry, has patient moved. You need to make sure all of those are correct before you do anything, then I use scalp to look at the skin so that's just looking at the skin itself, then looking at the connective tissue so you can see the skin uh and then you get all of that in between is what we use the scalp. However, when you get bigger hemotomas, you can normally use scalp to look at the apnea, races too loose connective tissue and periosteum, it's not that important it's just something that I always feel like you should mention then. Um you work from the outside in, um so after doing right patient right date, um checking that the skull and the scalp is all ok, you then go for the skull is the scotland tacked, are there any breaks in the skull. Um Can you can you see anything wrong with it um in, then you then move into the extradural space um things like uh middle meningeal arteries might possibly there, then you look at the subdural space the subarachnoid space, then you look at the cranium it's uh sorry the cerebrum itself looking for any bleeds or anything like that, then you look at the middle midline and then you look at the ventricles. This is the best way of presenting it just because when you are presenting a ct um just skipping too well. This is a problem, sometimes in an oscar or even on towards you might know you might know absolutely everything there is to know about cts, but sometimes you just get it wrong what they are looking for. Specifically, an oscar is is to make sure that you know how to interpret. So if you just go well, this is a intracranial bleed and say nothing else they, if you've got it wrong and it was something else. They don't know your thought process, always talk out loud um and if you get lost, just remember, check symmetry check csf spaces look for gray white differentiation and the uh parenchyma and then look at the bones, sciences, and orbits just to see and now let's just quickly talk through this um normal seating head um So for example, this cT head was performed by mr, jones on the well today. The CT has been performed due to meet nice guidelines, so you're walking along you're working along here. There's no breaks in the skull. There's no came at home of this book that is completely normal temporal um just skin you're working there. This is your sinus here, there's no breaks in the skull. Um Then there's no blood visible in any of the dural space. Is you can't see any subarachnoid you've got to white things here and here being the current place, plexus plexus I um There is no midline ship because it's equal, straight down the middle, and you've got vegetables here here here and here completely normal now, let's just move on to the next one, now, let's move on to the actual interpretation. Um I've just run through absolutely everything here, the one thing that I haven't mentioned yet is talk about pathology. So sum up everything, so after you've talked through, absolutely everything there is to talk about in your ct heads, some of what it is so sit there and go. In conclusion, this is a normal CT head. Or in conclusion, this is a subdural and then you can move on in your station. Um The most common cases that you actually seem to see in Aussies and even generally, just when you're out working is um uh extra euros subdurals, sub arax contusions sometimes fracture the surprisingly common and then um attenuation either being acute or chronic Depending on the age, you are now, let's just quickly talk through extradural hemotomas, so the typical presentation of an extradural hematoma is a young patient normally involved in a head strike uh This is either during sport or result of a motor vehicle accident um and they may or may not lose consciousness transiently um following the injury, they normally have a lucid interval, but usually have ongoing and normally really severe headache. Um Over the next few hours, they gradually lose consciousness just due to uh the amount of pressure put on their brain um and uh if you're always struggling to remember what causes your extradural hemotomas um effectively is the artery, so you're juror during, um when we are maturing, our juror effectively bind to different suture lines in our skull, and when our skills fuse, the jurists stay within within those sexual lines, which is why we call them section lines and in order to push that juror away from the scalp, you basically need a ridiculous amount of pressure that can only be generated by an arterial bleed. This is why your middle meningeal arteries are the cause. A few extradural hematoma us, um or hemorrhage is for that matter um and it's typically a lentiform shape as you can see here. Um It's I like to remember it's a lemon shape um and it doesn't cross future lines because your jury, your jury is basically contained to only one suture line um It's also limited by sutures unless disrupted, so sometimes the pressure gets too great and it can eventually burst with that. You're more getting into end of life care than uh and the mass effect, so here mass effect is effectively where you only have a set amount of volume in your skull unless you permeate, so you normally have brain you have blood and you have csf, you can only have all of those plus a small little plus a really really small little amount of something else in your brain. If you get more of more mass, something has to give and normally that is blood and csf. Eventually you reach 100% and then your brain slowly starts to ship. This is why you get things like herniation and you can see here. It's actually pushing across the midline there. Because of that, there is nothing is like, so there is midline shift in this patient moving on to a subdural. Um This I always like to remember a subdural because of this looks like a banana um and that has gotten me through five years of medical school um so give or take what you want from that but subject in subdurals um it's normally in adults um and it's normally due to falls, but there may not actually be a clear history of trauma. Uh In young children, the subdurals that you see tend to be n. A. Eyes um and that's generally the most significant cause um The patient's level of consciousness tends to decrease gradually. Um This is men mainly due to the increasing mass effect and confusion that occurs. Um. It's also seen in elderly and alcoholics as well, which is a progress test or past med question for those of you in your clinical years um the it's almost always venous due to tearing of the basically subdural cortical bridging things which extend into the dural sinuses causing the the effect that you see uh is completely crescent, eric, it's concave and more extensive than extradural hematoma um As these occur in the sub dural space, uh they cross sutures because they are below the juror that has already fought, fused to the skill, and as you can see here, and again, you've got you've effect, effectively got fast mint over the ventricles here and here a fast mint basically needs just shifting um other than that we move on so quickly, let's just talk about a dense m. C. A sign, um so the dense m c. A sign is only seen in your very, a huge patient's um and it's transient sign, It's only seen within about an hour of the steps trick actually beginning and at that point um you just treat the stroke. Um If you still have a patient that comes in the stroke like symptoms, you would still treat them full stroke even if you can't see a dentist, m. C. A. Sign, just because it is so transient that the dense emcee, a sign is just ridiculously rare. Um It's also known as gaps sign um and basically refers to the hyperdensity, hyperdensity right here. Um Normally, you would actually have to trace the the entire cT to actually bind the m. C. A. But when they give you something like this, you can effectively just pinpoint it and just pin your hopes on m. C. A. Um uh It's the hyperdensity is effectively um due to the arterial content, basically having a thrombus in the thrombus normally goes after a while. That's why we don't die when we have a stroke um and it's sensitive uh sensitive in approximately I believe it's fake percent of patient's whilst it's highly specific um It's a I believe it's a 90 to 95% specificity for this condition moving on to a subarachnoid um So s h is basically another type of intracranial hemorrhage and basically this specifically denotes the presence of blood within the subarachnoid space. Um The your patient's here tend to be middle aged um typically less than 60 years old normally um from anecdotal evidence between the ages of 40 and 50 and it effectively accounts for 3% of stroke and 5% of stroke deaths. Um Your risk factors are family history and hypertension, heavy alcohol as well and abnormal connective tissue um and your patient's will either present with a thunderclap headache, which is a typical pass met answer, or um g. C. S. 7 to 9 fluctuating um frequently. Um Often will denote a subarachnoid as well um in almost half of the patient's that you see is associated with the collapse and you for his loss of consciousness even in patients who subsequently regained consciousness and have a good g. C. S. Trying to think in rule out subarachnoid hemorrhage is um and here you can actually see that it is caused by a aneurysm or uh in the m. C. A. So normally what you would do is. If you do see this, you would effectively go in um through the thigh and you would coil the aneurysm there. Um The other thing just to mention is that I always look for the saddle of willis. When I when I, when I'm talking about subarachnoid hemorrhage is in this case, you can see it very clearly, so you know that it is a sub barack um and then cube contribute um so effectively um let's just quickly talk through this ct, so again you have the sinuses here and here that is again just effectively a sinus uh and all of this basically intracranial bleed here and here here and here is a coupon to group, is effectively a hypertense lesion interested uh cerebral bleeding in the frontal lobe and temporal lobe bilaterally uh and that's normally what all you need to diagnose acute contra group um So this is the term that we apply to head injuries and most often cerebral contusions and traumatic subarachnoid hemorrhage is where what happens is you are in a high mechanism injury um and your head is effectively thrust against something um to the, to the point of maximal trauma occurring at the front of your head. Your brain then shifts backwards uh in your head and as you realign, your brain shifts forward again which is why you get multiple um intracranial bleeds at the front, a couple normally in the back, you don't see it in these, but you can see it bilaterally here as well. um the main thing basically what you have is um the impact accelerates first uh the skull, at which point the brain basically subject to damage as it's fourthly impinged on the cranium itself. Um shortly after the intercranial content has accelerated, um too basically the back of the skull again and then the front, which is what causes this uh this trauma. Um It's most like um uh one thing that we commonly see as well in cube contribute is traumatic lens dislocation of the eye as well. So if you have a patient that comes in that can't really see has been in a high impact injury, you would normally really be worried about coupon tribute and the management of this is unfortunately just to put an eye seybolt in and measure the ICP and treat them as per uh you're raised ICP protocol so hypertonic saline as opposed to mannitol um We are generally moving away from mannitol now just due to the fact that mantle is a diuretic and the last thing you want to do is also dehydrate your patient as well um nursing them at 30 degrees head up and just trying to keep them comfortable um hydrocephalus as well. It's another important thing um although it is typically referred to as either being obstructive or communicating, I find it can often lead to confusion as the underlying cause of basically what you see in. The ct is ventricular megaly um as basically the different terms referred to different underlying fizzy pathophysiology, but in a ct head, it doesn't really matter whether it's either of the two, you just need to look and see whether they're enlarged and know the management um what you can see is the hypodense lesion here is effectively just to see csf um and this is effectively in obstructing uh the normal flow of csf through the basal systems and by filling basically the uh arachnoid, I believe that's the arachnoid granulations because you can't because your csf can't get through it effectively just collects in the ventricles and expands ventricles outwards, which is why you get this massive pattern here. Um The it's either acute or chronic uh this would be more of a chronic picture. Um Sometimes you will be given just very small hydrocephalus and at which point you you the ventricles are slightly smaller but still quite quite big and you should also compare the hydrocephalus to a previous ct as well so moving on to another poll um What is present in this ct cool, so the majority of you put uh deA, i. And that is in fact correct um so I always want to think of d. A. I. Um and normally you can tell before you actually reach uh inside the cranium. Just do two you can actually see that there is bilateral swelling in the, in the scalp. There uh sometimes you see breaks in the scalp. In this case, you don't um basically uh d. A. I. Used to be known as traumatic ac, zonal injury um and basically is a severe form of traumatic brain injury um and it's normally due to just shearing forces. Um It is arguably the most difficult thing to diagnose. Um on ct alone, you normally just have to look at your patient as well as there's normally severe neurological impairment. Um Actually the diagnosis is best made in the mri, where is characterized by several small regions of what I believe is a susceptibility artifact at the gray white matter junction in the corpus closer um basically um due to the different forces of gravity's um and the change in velocity um It has basically a predilection for tearing axons off of the great white matter junction um which is what causes this um and what actually then happens is these forces result in damage to the cells and result in adama um complete tearing of the axons. Is really only seen in severe cases um. It is also known that some neurons may undergo degeneration in the weeks or months after trauma, which can be called secondary. It's uh secondary axo axon, Matisse's, um but basically a noncontrast ct of patient's is routine in patient's presenting with these sort of head injuries. Unfortunately, because it's not so sad till it's often missed until we do do a, an mRI, but once we've seen that there's soft tissue spell uh swelling, The bone looks completely normal. There's no bleeds because there's no hyper or hypo dense illusions anywhere. You've got a bit here but that's more gray white and you've got the corridor processes bilaterally as well here and here no um you can also see that there's just no gray white matter, it just looks completely gray, which is indicative of just a share share forces, so another thing to make sure is that you know what a normal child brain looks like. Um Children are not small adults. They have many physiological and anatomical differences as you can see. The ventricles are really really small you can't really see anything. It almost looks like a diffuse axonal injury, but you can just about see gray white amount of differentiation all over the scalp all over sorry all over the skull, and that is that's the important thing to tell you that this is the child. The other thing is that the head is normally more circular than an adult as you can see between this, where it's more I like to think of it as long as opposed to almost a perfect circle, and that's not important thing to remember, um that the other thing is the only time you'll normally see a normal child. A child's brain is in an ai, so it's also important to look at previous surveys they have they've had them or if not just always google in practice. Um So what is present in this ct wow, thank you, we will give it five more seconds just guess if you don't know okay, perfect, so the majority of you guessed e, um and that is actually the correct answer, um. And we will just talk through this. Um So intercranial tumor's comprise effectively a group of tumor's that are just they're effectively a group of tumor is that where you begin to see the mass effect showing um in adult patient's, the majority basically represent metastatic disease, with a small proportion being primary brain tumor's uh metastases um to the brain occurs most commonly from the lungs, uh the breasts, melanoma, renal sales, and colorectal cancers. Um with the city often being the first line test. Um Due to their neurological deficit um, hypo or hyper dense irregular lesion's will be well well defined um either peripherally or using deep tissue print uh perforation. Um You can often with humans see a mass effect exhibiting as you can hear uh. The main difference between why this is a tumor and not an abscess or anything else is that it is unilaterally one color with an abscess. You would normally see different colors and different densities just due to where the fluid is collecting the same thing with the cyst. Um you can also see um it's always useful as well to do a contrast ct, so this is actually a contrast ct. If in the very first line, most radiologists will only do a just a normal head ct, and what this often means is that you can just about see the just about see the tumor, but you can't see it properly, which is why often you will have to send your patient back to the ct scan er with the line in, in order to give give them contrast to actually see it, but the ct itself is especially helpful with bony involvement. You can see here that there is no bony involvement just due to the fact that it is hyperdense all over um moving on what is the most likely cause of this depressed skull fracture. Let's go for two more people, if you don't know just gest's one to there we go ok. So the majority of you voted for bat versus hammer and ball and punch. The correct answer is a hammer um and this effectively requires you to look at patterns of injury um so if we start off with bull um it could be a bull. The problem the problem is that it is it has a central punked um right there with a break there and another break there, so it could be a bull apart from the very, the very bottom right here, which looks almost like something has actually sat in it a bat If someone was to take it back to you, uh it would actually you have a more depressed skull fracture long hair uh just do two. If you're swinging a bat somebody um it's unlikely to just be the end bit um a punch. As well traditionally, we actually see the punch is at the very front of a patient normally around the orbit uh as opposed to the temple um and a hammer is the most likely just due to the amount of tissue swelling here um The important thing as well and we will move on to the next slide. Um The important thing to know is that press, golf reactions result in the bones on the skull vault effectively being folded inwards into the cerebral parent, Calmer um it is usually the result of the high energy impact in order to generate those forces, it needs to be something normally metal um or in unlucky cases about or really really fall fall from height um and effectively 75% of them occur in the frontal, parietal region, with the remaining 20 just happening in the frontal region. Um There are a number of associations that can occur and these are normally, extradural hemorrhage is subdural street wall contusion. Sub arax basically everything we've talked about today, but the key thing to do is um remember that this is actually a bony window, so of your ct scans, you'll actually have two windows, you'll have your the window where you can actually see all the brain matter and then you'll have the window where you can actually see your bone matter. Uh sorry, just see your bones and it's always important in practice once you checked your the first window to check the second window just because that's where you can actually see the breakages. Um CT is the modality of choice, especially in head trauma, which is why you can see this um and when you are looking at soft tissue damage itself. Um If there is any bit of black air so normally like you would see there but bits of black air there and there and you can presume that there's a air normally caused by breaks in the skill. So without looking at patient's sometimes you can sit there and go ok well. They they have embassy uh surgical emphysema, they have emphysema, so it's most likely to be an open fracture treatment for this is effectively keep them elevated and surgical debridement and that completes our session. Um We'll just go through again once more how to interpret and that's right patient right date um Why are you doing the CT uh then moving on to scalp checking the skin, checking whether the scholars intact, then looking at the extra little space is your subject of spaces, your subarachnoid spaces, and then looking at the cerebrum, the midline, and the ventricles. If you do it this way, you will not miss what you're looking for this is why you will only see a uh diffuse axonal injury in at number eight or uh ventricular enlargement in number 10 and then finally summarize what you found and then just at the end, I've attached just some things to get you better brushed up on your brain anatomy. Thank you very much. If you fill out the feedback form, you will get the slides after I've changed a couple of things, but other than that thank you very much