Chapters Transcript Back to Basics for the sake of time, I may only touch on one symptom or syndrome on a given slide. There's more details on the slide, but just for the sake of time, we may limit it to the important ones, um, or review here. So again, moving through our cerebral vascular system will start at the heart. As you know, four chambers blood goes in the right side gets oxygenated out the left. Once it comes out of the left side of the heart, we go up into the aorta into three primary vessels are break gives the phallic trunk, which then gives off are right. Carotid are right. Common carotid are left common carotid and the left subclavian. So we're going to you come back to this imaging frequently in order to kind of point out anatomy and just start with we have our aortic arch. That's where our blood begins. To get up to the brain from there, it's going to travel upwards through the break yourself, Alec. Artery, um, and off to your left, you'll see the right subclavian artery, the right, the right common carotid ID and the left common carotid as well as the left subclavian that we just discussed. Um, moving down now to our carotid arteries, internal and external. We'll look at them in a variety of ways just to kind of get a better idea of how they course in atomically and what branches they give off. You can see an angiogram here with the I C A as well as the east to so are right carotid bifurcation. Where we're splitting into internal and external, we can see our right internal carotid artery here external and then to go over the other side are bifurcation the internal carotid artery and the external carotid artery. Um, the external carotid artery is giving up quite a few branches early on. Uh, if we start approximately going distilling the branches or superior thyroid is sending for India lingual facial, occipital, posterior, auricular, superficial, temporal and maxillary Uh, in medical school, I had trouble remembering things, and I had to come up with a pneumonic for everything. The one I used for this with some attendings like freaking out poor medical students, it is still true different. Look at the external credit artery because again, those vessels don't necessarily stay perfectly in line exactly where they're supposed to. You know exactly where they come off. Uh, they may cross each other. They don't all come off at this same direction from the E. C. A. And we have overlying anatomy, complicating that as well, going to our internal credit artery Some of the segments that we'll talk about our cervical, uh, which does not have any branches. The Petrus. So which is going to give off panic branches that supply the middle ear cavernous segment? We'll talk about that in just a moment and are Super client ID segment, which does also give off some branches. Here's an angiogram kind of looking at the segments. Here are surgical's most proximal to the Petrie's will serum cavernous clay annoyed ophthalmic and communicating again as a medical student, having different well as an intern having difficulty with anatomy and memorization. My new manicure was Cleveland. People love Cleveland Cavaliers, of course. So you know, just in case. All right, so to go buy these segment by segment, our cervical here has no branches, so it's going straight up to the base of the skull. We're going to get to their Petra's. I see a uh so that's gonna come up a little bit further, right at the beginning of the cavernous. Uh, I see a portion and are cavernous Sinus. The carrot runs as well as some of our cranial nerves. So cranial nerve 34 parts of five and six issues in the cavernous Sinus cause problems with all of those. And then we get up to our super clean out. I see a and this is going to give off. Multiple branches are ophthalmic artery here, the p calm and we'll talk a little bit more about that later. But essentially connecting the posterior and anterior circulation And in our interior core oil, uh, supplies many different areas in the brain, including things involved in vision and our amygdala as well. So when we think of an I c. A syndrome, we're thinking of essentially almost all of the anterior circulation on that side of the brain, all of it. So that includes M. C. A and A C A. So n IC syndrome essentially includes both of those. You can also have its lateral vision loss. Um, and you may actually have P CIA involvement as well, and we'll talk about those other arteries in a moment, but occasionally RPC comes off of our anterior circulation that can cause an even larger stroke. If you were to have an icy occlusion, our interior colloidal artery which we just mentioned, um can cause both vision and, uh, motor losses and then just kind of give you a couple images here we can see some calcified plaque here in this karate kid. The karate doesn't always look perfect. Like our source imaging that we were using to point out anatomy. We may have some calcium or plaque. You may also see some stents. So some various things that you may see on imaging Alright. Moving on to our vertebral basilar system. So this is we're now looking at the posterior circulation in the back of the brain to go back to our imaging. Here are vertebral arteries on each side. Those are actually depth is a little hard in this, but they're coming up behind our carrots. Um, and it's going to come up again through the phenomena of C six up to C two. We're gonna kind of go loop around this Atlanta occipital joint, and that's after that is where we become intracranial. We go through the dura, we become intracranial, and those vegetables come together to form the basilar artery. Um, as you can see, we can follow that basilar artery up the ponds. Uh, it's giving off some Ponting perpetrators small vessels that we can't really see very well here, up to the very top where we were going to split off into our posterior cerebral arteries. Um, issues at the top of the browser can cause a variety of symptoms. It can cause bilateral strokes. You can have sensory issues, motor issues. Um, I abnormality is so really quite a few problems. Uh, and then, as I said, we give off our posterior cerebral arteries. That's going to supply a lot of things from the back of the brain, the cortex, occipital lobes all the way from to some of our deep structures, such as the thalamus. So, as I said, depending on where you are at and that's a serious cerebral artery, many structures might be involved. This is giving us an idea. As I said, not everyone's anatomy is exactly the same. So the territory is covered by a certain artery might vary slightly from person to person. Um, this the darkest shading you see on this is going to be the minimum territory that is typically supplied by the posterior cerebral artery. The in between gray is the more normal territory, and the very lightest gray is is sort of the maximum that might be supplied by the mysterious cerebral artery trump. So various syndromes and symptoms we might see with the P C A occlusion, uh, sometimes in those little perforated is causing the Kunar strokes. You might see crane on their three affected or eye movements, and you may have weakness. But you may also have abnormal movements in the contra lateral body because the supplies are a sip, it'll load. We may also have vision problems and some interesting syndromes. And patients may actually deny that they have vision problems and be unaware of it. Um, forgive my crossing arrows here. So our Sarah Bella arteries, we're gonna start with our pick up the most approximately coming off of vertebral, followed by our anterior inferior Sarah Beller artery coming up kind of at the base of the ponds there and then our superior cerebral artery, which is going to be that one just under r. P. c A. So the pike, as we can see here, Uh, and that's going to supply parts of the cerebellum as well as the medulla. As we go up to our I see our excuse me, our ICA or anterior inferior cerebral artery. We can kind of only see that on one side in this image. And then, um, are superior cerebral arteries which are coming off just below that posterior bit of an easier schematic to see here as we put those vessels up against the brain stem. Um, again, the fat basilar going all the way up to the ponds with the superior cerebral artery at the top of it. I guess, somewhere in the middle going down and splitting into the two vertebral. Right? Um, Sarah bellum can cause a lot of symptoms as we know some vertigo, nausea, vomiting or big ones. Uh, patients tend to complain about occasionally with swelling of strokes in this area. If you have compression of that, uh, if you if you are not allowing CSF flow, you may end up with hydrocephalus or altered mental status. Um, we can also see Wallenberg syndrome. It obviously involves the cerebellum, and with Zika strokes. You could also get some hearing loss. So some kind of interesting symptoms from strokes back there again, talking about Wallenberg's syndrome are medulla can cause some interesting, uh, stroke syndromes that can affect both sides of the body differently because of these brain stem areas and the tracks that pass through them as well. Same thing in the ponds where you can have cranial nerve involvement. You can have tracked involvement and may actually end up with different symptoms on each side of the body. Okay, so we're gonna move on to our circle of Willis and their large branches in the brain. Um, so we call it a circle of Willis. It was actually originally, uh, called the cerebral and a Tom, and in most countries is this is the polygon of Willis. It is a little bit more of a polygon as opposed to a circle, but we'll go with it. All right, so there's a bunch of parts to our circle of Willis, and we'll touch on each of them individually. But our I C has come up, provide our anterior circulation, the bazaar in the front, the middle cerebral arteries, and then in the back are vertebral are coming up with that posterior circulation forming the basilar, giving off the cerebellum arteries we already talked about and then our posterior cerebral arteries. This is our circle. It's not exact, but we're going to call it that. So again, starting with the top of the basilar here. We've already discussed that there is a plethora of symptoms that can come from issues there, And then we're going to give up our posterior cerebral arteries. So this is our P one segment. Um, the P Column, as I said, is kind of what's connecting our anterior and posterior circulations. Some folks may not have a pickle on one or both sides, but in the classic circle of Willis, that's kind of your connector. All right, from our anterior circulation, our internal artery, internal carotid arteries are gonna come up and give up our anterior cerebral arteries. So the A one or that first segment those are coursing through heading towards each other. They're also going to give up our middle cerebral arteries, which is going to supply a huge part of the brain. Uh, so it's the largest branch off of the I C. A It's the vascular territory where most strokes do occur and we can see it here in this. So again similar to our posterior cerebral artery. Not everybody has actually the exact same territory covered by the middle cerebral artery. Um, same story here. The darkest gray is sort of the minimum area that your M C a wood supply going to the lightest gray, which would be the maximum area that your M c A wood supply. But there is definitely some variability person to person looking at some of the parts of our M c A. So we'll start with the stem here. That's coming right off of our I c a. Giving off some of those smaller vessels lenticular strikes, supplying some of the deep parts of the brain Going out to RM two. So we're getting ready to split here and then are more cortical branches supplying most of the cortex? Um, I'm sure many people in this room taking care of patients with M C A strokes. Uh, depending on what side and exactly where they are. You can end up with many different symptoms, but weakness, sensory loss. If it's a dominant hemisphere of Asia, are very common. Um, non dominant hemisphere may include things like neglect. Patients may deny that they have a stroke at all. All right, and then our anterior cerebral artery. So this is coming forward, kind of on the very internal part of the brain. Um, coming up above our corpus callosum. Here, as with everything else we've discussed, there is some variation among patients and how much that a CIA is supplying. So our darkest gray again is the minimum that we would see our supply to the lightest grade being the maximum. Um, one of the things that kind of separates that from an M. C. A syndrome is we might see more leg weakness. If somebody's anterior cerebral artery is occluded versus their middle cerebral artery, we can follow that here in this imaging, um, to go through our segments very briefly here again are a one segment of that first segment is going to be the most proximal, um, are two a CS are going to come very close to each other and actually be joined by our a calmer anterior communicating artery that links those two together to form that whole circle of Willis and then we're going to go up into our peri callus artery. So this is the one going up near the corpus callosum giving off these branches that are going to the cortex again, AKA syndrome is going to affect the leg more than the arm and syndrome, and we can kind of see both the A and M to hear in this angiogram another interesting stroke type or stroke area that we might see in our patients or watershed strokes. So those areas that are between two territories are very prone to being affected by things like low blood pressure impaired profusion, so hypertension during surgery can be a big cause of these types of strokes. So those border zones between the A. C and the M C. A or the M C and the PC A are very common areas for these strokes. We can kind of see here if each of those main arteries or is a different color. The areas where those two colors come together are the most at risk for watershed. Okay, so briefly. Now we'll go over our Venus system. Um, so there's a lot of aspects to it. We look at it less frequently than our material system. We have fewer patients, but we do have patients coming in with Venus and Forks. So we have our superior sagittal Sinus, inferior sagittal Sinus. Uh, near the bottom are transverse Sinus going down into the sigmoid and then the jugular vein. We also have that cavernous Sinus there that we mentioned earlier, which has, uh, also near parts of the I C A. The internal carotid artery as well as some cranial nerves. This is a different views of kind of looking from the back here again, that superior sagittal Sinus down to the transverse sigmoid and internal jugular. We look at it from the side, not quite as well defined as our nice little diagram. But we can still see most of our Venus anatomy here. Alright, Kind of a blow up of our cavernous Sinus here, because again, issues here can cause problems with our cranial nerves. The internal carotid artery. Those are all running very close together. And now, with just a couple minutes left, I wanted to show some imaging for each of these strokes to see what we might see on a patient's m r. I. All right, so here. We have quite a bit of frontal involvement, and this is actually a superior left, like a stroke. So if we look at where that red dot is, that's approximately where we would guess thrombosis or a clot or cut off might be for this patient. So everything beyond that has infected, which is giving us this MRI. All right, so we've done Superior, uh, this summer, I also a sizeable stroke that that's going to be our inferior division. So a clot or issue in that inferior branch, still fairly proximal, could easily result in an M. R. I like that. Those are the C T head, Um, and this is also a pretty sizeable stroke, and we actually are, including both superior, inferior divisions of the EMC and this because this is going to be a stroke that happens even more approximately. Even before those branches split and results in a fairly large stroke affecting all of the territory. Those patients are going to have quite quite a deficit, particularly if that is happening on the dominant lobe. All right, and then here again, we're looking at something that's kind of very near the middle of the brain. Very anterior. So this is our interior cerebral artery. The portion of it coming up and feeding the cortex here. Okay, Now we're in the back of the brain. So an MRI like this might be from a PC, a stroke or that posterior cerebral artery stroke. But depending on where in the p c. A. That stroke occurs. You may have very different imaging. Very different stroke symptoms. Um, and here with just a small a very small stroke. That's also an M C. A stroke. But again, we're looking at the small vessels. So strokes in the same territory may look very different, both clinically and on imaging. Just depending on where that clot happened. How approximately? How distal. Okay, now we're down in the cerebellum and the brain stem. So this is our pick a stroke. Um, again, our Wallenberg, uh, artery here. The pika causing issues in both the brain's town as well as the cerebellum. And we're up in the ponds. I think you can. The first image is a little hard to see, but the brightness on the third one is much more obvious. So this is a little perforated artery stroke coming off the basilar artery going into the ponds again. Those perpetrators are hard to see on our source imaging. We didn't get to see those, but the very small feeding pieces of the brain stem and can actually cause very significant symptoms despite a small stroke because of the density of tracks that are going through there. All right, and yet again, our brain stem here also a PC, a infarct again, probably a perforated branch. So smaller area compared to our more proximal inclusions. And this one is a basilar artery stroke. So if we go here, we actually see that were affecting both sides of the brain stems. This is a bilateral stroke. There's a few places that can cause bilateral strokes. The basilar artery being the most concerning. So a patient with a basilar artery stroke that has bilateral brainstem involvement is at risk of developing like a locked in syndrome. And here we have quite a bit of cerebellum stroke, So this is going to be our pika again, but a larger area of the cerebellum and again going back to the posterior area of the brain. Um, this is more proximal posterior cerebral artery infarct with R three is probably somewhere around just where that pizza is coming off the Basilar. This, um, this is probably one of the more devastating strokes in our imaging cases, and it's a bit tricky as well, because it doesn't fit a single vascular territory. So we have almost an entire hemisphere affected both anterior and posterior. And again, the reasoning for this is because sometimes that posterior cerebral artery can actually come off of our anterior circulation and come be fed by that internal creditor, right? So if that is the case and the internal credit artery then becomes occluded, you end up in farting. The anterior cerebral artery, the middle cerebral artery and the posters Cerebral artery can get a hemispheric stroke. It's very unfortunate for those patients, so as we see, this is a posterior cerebral artery that has a fetal origin, which is how we essentially means that it is coming from. The anti air circulation are off the to all right, thanks so much, and All right, more basic anatomy. Our second speaker for stroke neuro imaging, 101 is if a dragon. So he's the chief neurosurgery resident and has completed a neuro interventional fellowship as well. Yeah. Good morning, everyone. Thank you all for being here. Um, I think nowadays it's so important to be informed about stroke, and I think by attending events like this really lets you have conversations and participate more effectively at the forefront of this rapidly evolving field. So, um, thank you for the opportunity to talk about neuroimaging here today. See if this works. I've no disclosures for this talk. And whenever we talk about neuro imaging and stroke, I think the biggest question to ask is, Is there a perfect test? You know, in a pathology where every second counts? Is there really a perfect test that can help not only identify the problem, then help escalate that to allow the interventional team to make a formal decision on on the stroke? That's actively happening and a perfect test should be rapidly obtainable. It has to be able to differentiate ischemia from hemorrhage, and it's got to exclude stroke mimics, I think, beyond that, assisting the status of the major blood vessels that we commonly intervene on. It's also helpful and a test that can accurately estimate the volume of the infarct core and the penumbra. That's kind of the crux of neuro intervention is whether or not there is in this path. And there is no perfect tests, but a test that comes very close to all of that. What a cliffhanger. The C t So CT allows you to do all of these, uh, bullet points in a very rapidly obtainable and reproducible manner. Um, and C t, uh, is it stands for computed tomography. For the longest time, I had no idea what tomography meant, but essentially is a technique designed to demonstrate a 3D object in a two dimensional fashion, whether that's through X ray or ultrasound. And in my point of view, CT is absolutely the preferred initial imaging modality. Its availability is widespread. Acquisition times are rapid, and CAT scan can really serve as a single stop. That can help make the entire decision regarding someone's show care. Well, what about renal function? I think early in residency seven years ago, there's a lot of concern about, you know, are we harming patients by exposing them to see to before getting a renal function panel? And the answer is no. I really like this title of this article neurons overnight. Franz. I'm very biased towards it, but essentially described that getting a C to um prior to knowing someone's renal function status is really not harmful. The likelihood of you causing a hemodialysis dependent Renal injury is less than .1%. And I think that's very important to know not only an ischemic stroke, but also in a situation like a subarachnoid hemorrhage when you have to know whether or not it's a ruptured aneurysm. CT is the best test to identify that, and there really isn't any justification for delaying a contrast that study like this based on someone's renal status. Even in the setting of chronic kidney disease, the rights of requiring hemodialysis is very low for this. What about MRI? MRI has its uses. It's more sensitive than CAT scan for detecting acute ischemic stroke, particularly for small volume in parks. And I'll show you some pictures of representing that. It's equivalent to CAT scan, more sensitive, even and detecting hemorrhages, especially smaller hemorrhages. And with evolution in these M R protocols, the acquisition times That were notoriously in the past very long have now been optimized to be as fast as five minutes or less. Um, so a lot of advancements in our technology has been made it over the past several years, and it may also beyond. Cats can identify the stroke onset timing. You know, I'll talk a little bit about the the fusion flare mismatch. This is just an example of a hemorrhage. Rule out, um, someone comes in with how many allergic symptoms, and you get this CAT scan, you automatically know they're not getting T. P. A. Can see very clearly that there's a hyper dense lesion in the left thalamus. And, um, hemorrhage on CAT scan is very unambiguous. And that's one of the advantages of getting this CAT scan. There's something called the hyper dense M. C. A sign. It's oftentimes far more subtle than this. But, uh, included vessel in the internal circulation appears as hyper dense, and if you have a large vessel occlusion such as approximately to, it'll appear like what the sign describes the hyper dense to basically hallucinate where the vessel would normally travel. And this is usually an indicator to us that there's a large vessel that's occluded early infarct signs. I think this CAT scan is, uh, very severe example of the point I'm trying to make. But, um, you really lose the sense of being able to see very clearly where those basal ganglia are. I think that's one of the earlier signs that there's already an infarct happening. The loss of the insular ribbon just means that you're not really able to see that gray white differentiation at the insular level. And later on in stroke, um, you start developing mass effect, meaning that the affected area of the brain swells takes of water and you start, um, losing the ability to see the critical soul side because the brain gets so swollen at that point aspect. Score, uh, is, um, a semi quantitative scale that we use to communicate with each other? Um, also something that we can use to rapidly assess whether or not someone may be a candidate for a narrow intervention. And it essentially divides the M C. A territory in 10 different uh areas, one at the basal ganglia level and three more at the, uh, couple slices immediately above the basal ganglia. But it's a very quick way to be able to describe what's going on in terms of how large a stroke is MRI gives you again the ability to identify these smaller infarct. These MRIs on CAT scan would be completely normal, but the patient still has weakness on one side of their body or a taxi that can't be explained. And the MRI helps you identify that. It's a really small infarct in that area. M. R is also very good and sensitive at detecting smaller hemorrhages or early areas of hemorrhagic transformation. Um, after someone has gotten t p A If they undergo an m r. I, uh, for example, in the setting of the NIH decline, uh, it may be due to early hemorrhagic transformation, and MRI is often times better at detecting some of the earlier signs of that, um, and the D wi flare mismatch. I think it's something that's not really talked about as much, but it's a very powerful way to just to identify the timing of a stroke. Um, sometimes you get these wake up strokes and you don't know if they're last. So normal is truly like before or within the last three hours, and MRI actually has the capability of being able to differentiate that you look at diffusion sequences and flair sequences. And if there's a mismatch between what the diffusion says is a stroke, and what the flare says is a stroke, that usually indicates that it's a very early stroke within the 1st 4.5 hours. That's powerful information to know, especially when you're deciding whether or not to potentially expand the indications of PA expanded indications of mechanical thrown back. To me, this type of biomarker is helpful to guide that decision. C T angiogram is very powerful. Uh, nowadays modern c T angiogram. The resolution of that is almost that of an angiogram itself. Um, some of the qualities of the cat scans that we get who's on the main campus really make our jobs as neuro interventional. It's easy, um, outlines the entire plan for you. Especially getting the head and neck down to the aortic arch helps us identify what catheters we need to go up with initially. Um, and it really helps build the expectation of whether or not this is going to be a successful thrown back to me. one of the main things we look for is whether or not there's any a pacification of blood vessels beyond the affected territory. So you can see in the middle of the screen that's a criminal CAT scan. You can see that the left M C a. Them one segment is blocked off distal to that, the middle cerebral Artery territory is still feeling somewhat, and that to us indicates that there's back pressure. There's let them NGO collaterals, and it really helps improve the likelihood of this being a successful come back to me because of that back pressure helping with the clot retrieval. This is another example CT angiogram. I think looking at these studies, you really owe it to yourself to look at all the different views and my perspective, the most confusing, um, orientation of the sea to us, the axle, even though that's the most common one, the more helpful ones are the corona and vaginal reconstructions, because they really help you identify where the stroke is, and it helps you avoid missing some of the distal strokes. A lot of the distal strokes are difficult to see on the axle, but they can become very apparent on the satchel when you scroll from the Sylvian fissure to the Sylvian Fissure and you notice that the line is missing. Um, CT profusion. It's a very cool technology. Uh, it kind of, um, over figure this out as a mathematical genius, but what it essentially does. I don't know if he has had a chance to be in the cat scanner when a C distribution is actively happening. But you may notice that the table's moving back and forth multiple times, and what's actually happening is the CAT scan is taking multiple different, um, scans of that same box that you see on the bottom left. So, from the base of the skull to the top of the skull, the scanner brings the patient back and forth through that field multiple times, as contrast is circulating in and out of their brain those curves that you see in the middle of the screen. The red and the blue curves are actually, um, Preset points one artery and one vein. And those curves are used to calculate these parameters called R B V, uh, CBF mean transit time, and helps us estimate what the penumbra is and what the core infarct does and and what the software for CT perfusion essentially does is it calculates those curves for every pixel there is in that CAT scan or what we call a box in a three dimensional pixel. And that helps us identify what's salvageable brain and what's already too far gone. The scheme of core is defined as increased mean transit time with a significantly dropped off blood volume and blood flow, whereas penumbra has preserved blood volume. And that's the key differentiator that a lot of these software systems use. And a lot of the, uh, expanded mechanical enemy trials were really predicated on having a CT perfusion or some sort of profusion imaging that fit these, uh, inclusion criteria of having a mismatch between penumbra and core and some degree of salvageable brain. So putting it all together, um, this is a patient that comes in beyond six hours. You can see that on the non con C D head. There is some evidence of early great white differentiation laws, but it's not bad. Usually we cut out it would define a large stroke as aspects of six or less, and in this case there's preservation of the deep structures and you can see on the sea to on the criminal segment. Um that there's a superior division of the ministry biography missing. And because this person came in beyond six hours, we got CT perfusion imaging and you can see really compare the image to the far left to the far right. The mean transit time shows us areas where there's slow flow and R B V tells us where the infarct is. And you can tell that R B V doesn't really show a major symmetric drop in volume, meaning that there's not really a large stroke yet. But there's a huge area that could potentially become, in fact, if we don't intervene. And that's the power of CG production technology. So we took this patient to intervention and had a great outcome First password capitalization. And just to show how powerful CT perfusion is in predicting the final infarct volume, Um, the R B V is on the left is pre intervention, And after the procedure and MRI gets done and it essentially matches at 1-1 in terms of what the what the final stroke volume is going to be and some kind of food for thought and questions to think about in the future. I think a lot of these questions will be answered in the in the future. Um, but there's some thought that you know the imaging criteria for Donna Diffuse. Are they too restrictive? I think in practice, we I always feel that there's patients beyond Don interviews that likely will benefit from mechanical. Far back to me. I think these trials were specifically designed to show a benefit, which is why the inclusion criteria is so tight, completely understandable. But I think in the near future we're going to see expanded not only time Windows but expanded tissue windows as well. And there's also this controversial thought that is profusion imaging, even really necessary is that extra scanned, even necessary beyond this for six hours in my point of view beyond six hours? If you know that you have a vessel that's occluded on C T A. And you know that on cat scan, there isn't a large infarct, and the patient has a high NIH that already tells you that there's a big penumbra, Um, and I'm kind of in the camp of Profusion imaging, not necessarily being 100% required beyond six hours. I think it may just slow down some of the workflow, but that is a very divisive camp under intervention. So that's my presentation. Thank you all for your attention. Happy to answer any questions at this time. Yeah. Yeah. Oh, yeah. All right. So do we have any questions for either, uh, Dr Duncan or Dr Diwan on neuro imaging or imaging selection? I think I'll start first. So, uh, in a week, for a while there, we were going straight to MRI, uh, to really get that diffusion weighted image as the holy grail of the core in fart. But that certainly was difficult to do. And getting CT perfusion studies is a lot easier. Um, So what do you think about the pros and cons and reliability and patient selection? And I think that's a great question. Um, Ralph, um, I think there's no substitute for m r in terms of defining with maximum accuracy what the infarct is. But I think the reason why trials like select two are coming out is because, um, I think we're pushing the boundary of what is indicated for, um, Mechanical thrown back to me. I think a lot of the times you don't really need to know with 100% accuracy what the infarct core really is, Um, in my point of view, if there is a clinical slash tissue mismatch, then nowadays there seems to be a good indication to go after the clot. I think the safety profile for mechanical thrown back to me is, um good. I think the feared complication is hemorrhagic transformation. I think even with larger in parts, that rate is 5-10%. Um, but the potential benefit to be gained from the vast arising that territory, uh, in my point of view likely outweighs, um, that risk. And at the end of the day, does it really matter? You know, whether or not you have a 50 cc core versus a 55 ccn fardc or I'm not sure it does. Um, I may be wrong with some of the results of these future trials, but that's my perspective on it. Thank you. Do you think about that roast? I couldn't agree more. I certainly am. Are is gonna continue to have a big Role in accurately defining core. But there are certainly situations in which you'll see they're not feasible. Not plausible at this point. I think imaging has a pretty big frontier in neurology, neurosurgery going forward and particularly in stroke. So I think that we might be having a very different conversation in 20 years. So some, um, small hospitals that may not have neurologists readily available sometimes use a pretty large imaging paradigm in the emergency room for every stroke alert. So some patients may get a C T A C T angiogram, a CT perfusion, um, without really using clinical selection criteria as the protocol. And so although that certainly is that, that additional imaging enhances patient selection and may help you pick up some things that might have been overlooked like pride. A lobe having neglect syndromes? Um, it's certainly additional costs. Additional radiation. Uh, you know the potential renal issue, although that's not a driving factor. Where do you think the sweet spot is? You know who should just get the C T. And who should go for the C T. C T. A. And then who should get the whole banana with the C T. Angio and profusion? Uh, I think that's also a very good question. I think dictating those, um, indications by NIH is probably the most feasible way to do it. I think if someone has an NIH beyond six, um, my perspective is I think getting a CT head Sita is probably the safest thing to do. And again, a lot of us in neuro intervention are kind of shifting to the idea that you can make the vast majority of your decisions even beyond the six hour time window with just the CT head and CTC A and being able to see that even remotely, um, can help expedite transfer that needs to happen or prevent, uh, unnecessary transfer happening. I think with those two studies alone, they're very fast. It doesn't require any superfluous software to interpret. I think you just view the image even remotely. You're able to make that decision. So I think C t head C T A. For NIH greater than six is always a good place to start. Uh, I would absolutely agree. It's interesting because there's a huge variation in protocols in this across the country. There's even one or two places in the country that are looking at doing turbo MRIs for all of their stroke patients immediately, Um, so there's obviously debate about it But with all of the information, you can gather with some basic vessel imaging as well as a CT head. That, to me also seems like a reasonable place to start to go to the other extreme of Do you need a C T A. To transfer a patient that is becoming more of a question. Are we going to transfer potential large vessel inclusions before vessel imaging from the field? And I would be against that. I think that that is trying to be a bit too minimalistic and again would create some unnecessary transfers and kind of burden on the healthcare system. So that balance between not over imaging, which creates its own burden to the health care system and patients in a time delay versus not under imaging, which may cause unnecessary transfers and different issues. It's challenging, but I think that I would agree with Dr John as far as kind of where that balance is. Well, you did some work on this, looking at patients who were transferred, who didn't have a large vessel occlusion who probably could have been maintained in closer to home for stroke care. And so, looking at, you know, at least in the U H system over the last. I looked at the last three years, but the three years even prior to that had been looked at as well patients that were transferred for throwing back to me and did not get one y. One of the biggest reason is there's a lack of large vessel occlusion, which maybe because there was not a c t a performed at the outside hospital, So there's clearly causing unnecessary transfers and is right now our biggest reason for transfers that do not go to front. Back to me. Any other questions, right? Yes. Hi. Um, so I have a question. I know most of this discussion has been about, like, endovascular treatment, and, you know, but what are your thoughts on So, like, say some of these wake up strokes that obviously don't qualify for T p. A. And you were talking about getting an MRI to possibly say when this occurred. Is that something that you would promote or something that you don't feel like? It would be necessary Using m r. As a surrogate for the clock. Correct. For IBT pa administration. Who wants to take that? I don't know the answer to that yet. I think that's still being explored. Um, I think that yeah, I don't think there's a good answer for that question. Um, I think if someone comes and I think it all depends on the severity of the symptoms, if someone is having a higher NIH presentation, um, I think you still should start with CAT scan and CT A. Uh, I think that's kind of the wheelhouse for for the radiographic work up. Um, but as far as whether or not an M r should be done to help time every wake up stroke, I'm not sure what the answer to that is. I I think that that's an excellent question and that there is potentially a role for M r in those wake up strokes. Um, again, I think you need to be a little bit discerning about who you're going to activate that kind of a protocol for, You know, if there truly is unknown, last nor normal To the point that we we have no idea it could have been even more than 24 hours, probably that's not a great candidate, because the likelihood of that being within these last couple hours by the time we get an m r and can get tp a running as low. Um, but if there are patients that you have a reason to believe, you know that they're likely to fall into that. I see. You know, there is a potential future for protocols being developed there. I know that there have been places that we've been looking into that, um, again, there's a little bit of variability of exactly when things show up on flair. So is it an absolute you can time it to the minute based on m R. I know you need other factors and need to be weighing other things. Looking at a CT non con looking for those early evidence of the skinny. But I think an m r. I could absolutely play a role in that. So there's these portable M. R s. Now, uh, don't require shielding. I mean, we could set one up right here on one of the tables. And if those become more, um, effective in terms of having them available in emergency rooms, you know, they're small, affordable. They don't require a special room. Um, you know, I think that we probably will shift to using that as our imaging paradigm. Even people that have implanted metal, they're very safe because of the very low, uh, magnet field strength, which is actually really good for diffusion imaging. Um, so I think that as technology changes, we may use our tools differently and better, um, for patient diagnosis and selection. Created by
