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Her research focus is on novel imaging techniques and focused ultrasound and brain tumors, but her clinical love has always been on school based anatomy and pathology. The desire to see more and no more has led her to pursue high resolution imaging of the school base that helped to visualize the anatomy she has grown to love. Dr. Alhalali also has a deep passion for open access education, and you can follow her on Twitter at teach play grub to learn more from her. She believes there's no greater impact she can have than using education to help other physicians take excellent care of their patients. We couldn't agree more Dr. Alhalali and are thrilled you're here today to share your expertise. At the end of the lecture, please join her in a Q&A session where she will address questions you may have on today's topic. Please remember to use the Q&A feature to submit your questions so we can get to as many as we can before our time is up. And with that we're ready to begin today's lecture. Dr. Alhalali, please take it from here. Thank you so much. It's really an honor to be here and I really want to thank MRI online for inviting me and give me the chance to share some of my love of anatomy and advanced imaging with all of you. So today I'm going to talk about MR neurography of the cranial spinal nerves that flow the school base. I have no disclosures. I long for a day where I have a long list of wonderful disclosures with people paying me much money but not today. So when we're talking about MR neurography at the school base, the first thing we're going to talk about is the technical consideration. The cranial nerves are different than all the other nerves that we usually image with traditional MR neurography techniques. So you need a special technique to be able to visualize these incredibly small nerves. It's just like, you know, if we're talking about the brachial plexus versus the school base, you're not going to have the same, you know, traditional imaging of the shoulder if you will for the brain. So the same way you won't have the same imaging for the brachial plexus MR neurography as you will for the neurography at the school base. Then one of the big uses of MR neurography is for pain syndrome and I'll talk a little bit about how I use that to basically help diagnose difficult and atypical facial pain syndrome. And then finally, some advanced uses of MR neurography is actually to help our skull based neurosurgery colleagues to better plan skull based surgeries. So let's first talk about a little bit of background. So let's talk about peripheral neuropathy. There are actually a very heterogeneous group of disorders. The way I look at it is the nerve is kind of the connection between the spinal cord and the muscles. The same way I bungee cord kind of connects you between the ground below and the cliff. And many things can interrupt you on your way down trauma tumor compression infection. And, you know, radiation therapy many things, anything that interrupts your travel from the top of your hill to the bottom, I can possibly cause disruption of the nerve and a peripheral neuropathy. But yet despite having an incredibly heterogeneous group of pathologies that can cause a peripheral neuropathy, they actually all look very similar when we get down to EMG studies. I kind of like to compare it to doing MR spectroscopy. You have tons of different pathologies when it comes to MR spectroscopy. But in the end, the spectrum all looks like decreased in a increased colon. Similarly, there's this very diffuse spectrum of peripheral neuropathy, for which you really kind of get only two basic findings on the EMG, which is the myelinating and axonal pathology. So we really have a gap that needs to be filled in helping to diagnose these disorders for our clinical colleagues. And this is where MR neuropathy comes in. You know, the same way MR and the traditional imaging can help you differentiate, you know, all these different pathologies the way a spectrum can't, you know, imagine if you had to diagnose all your brain tumors just based on a MR spectroscopy of the lesion, it would be impossible. So the anatomic imaging has an incredibly critical role in the diagnosis and care of the patient. Additionally, cross-sectional imaging could only demonstrate a mass compressing the nerve externally. But with the continued advance of MR techniques, we can now actually look for intrinsic pathology in the nerves. I like to use the analogy of it's like going from, you know, basically like like periscope, right, just lets you see that there's something there versus a microscope, actually being able to look inside the tissue and being able to see the intrinsic pathology inherent in the nerve. So how do we do that? So I like to use the analogy that it's kind of like MR neuropathy is for nerves, the way MR angiography is for vessels. The whole purpose is to basically get rid of the background noise and the background signal in order for you to be able to visualize the nerves. So they're very different techniques from a, you know, MR physics standpoint, but luckily for you, it's not an MR physics lecture. But the point is that you're using the same principle of nulling the background so that you're better able to see the object that you're looking at or are concerned with. So MR neuropathy, you want to look at the nerves just like MR angiography, you want to look at the vessels. So let's talk about how we do that. So Tim said, I mentioned, similar to angiography, we want to know the background in order to be able to see the nerves. So traditionally for larger nerves like the brachial plexus, we did this using first a fat saturation technique to get rid of like the bones, the subcutaneous fat. And then we would do a black blood technique to remove the signal from the vessels so that basically all we are left with are the nerves and you know a few small lymph nodes. Unfortunately, those type of techniques that work so well for large nerves like the brachial plexus don't actually have the spatial resolution to help us to visualize the cranial nerves at the skull base. So what we can do is we use a reversed steady state free procession technique. So everyone knows the traditional steady state free procession technique which is the fiesta imaging which we used to look at the cranial nerves inside the cranial ball. Now we just reverse that technique to be able to look at the cranial nerves outside the cranial ball. So the semen name for the fiesta imaging or steady state free procession is fist. So they just literally reverse the letters it doesn't stand for anything they just literally reverse it and so it's called a PSIF. So I guess we're lucky that GE didn't invent it because that would be called a ATSIEF or reverse fiesta. So it doesn't actually say anything but it's literally just a reverse steady state free procession sequence. So our protocol to look at the cranial nerves at the skull base is we use the 3D PSIF sequence. We do it on a 3T because we need to get incredibly small spatial resolution and we need to keep our time reasonable because we don't want the patient to be moving. We use a 32 channel head coil it doesn't get as good deep penetration into the brain but a lot of these nerves are relatively superficial so a 32 channel head coil will help save you on time and will decrease your image quality for the superficial nerves. We do 0.5 millimeter isotopic voxels and on a 3T Phillips scanner that turns out to be about a six and a half minute acquisition. All of the images we look at on a 3D separate workstation in order to make multi planar and curved multi planar reconformats of the nerve. Then in addition to our PSIF sequence we also do axial T1 weighted images and coronal stir images. In order to look for other things that may be causing peripheral neuropathy remember it's not always intrinsic topology right. We're at the skull base there's still a lot of perinural spread of tumor so you want this T1 weighted images to be able to make sure your fat planes are all preserved around your nerves. And then of course the coronal stir images are helpful to look for any sort of muscle signal and the T1 weighted image also for muscle atrophy that may be a result of any sort of nerve injury. So we actually literally will trace the nerve on our curved multi planar reconstruction to kind of lie it out along its course. The same way that many people in CT and geography will lay out the carotid along its course, which is really helpful because a lot of times you're trying to figure out if the nerve is thickened so it's helpful to be able to look at the region you think is thickened. Next to a more normal appearing region right it's almost like a nice that right you want to compare the region of snows this or enlargement for a nerve with a more normal region. So, the big application of the MR neurology the school base is basically for craniofacial pain syndrome. The biggest of these is obviously going to be tried to have a neurology dwarfs any other pain syndrome in terms of the population that has it, but also, there can be glossopharyngeal nerve syndromes, glossopharyngeal neuralgia, and of course occipital neuralgia is a big problem in the headache population as well. So some novel uses that we're trying to use to apply this MR neuropathy is for more untraditional pain syndrome so video nerves the cluster headache. And then one of the important things we're using it for is with our school based surgeons to help inform their operative approach, being able to visualize the facial nerve for prodded syndromes being able to determine if you have a post pylate or paraphernal space mass which nerve it may be arising from. And then of course just to help them counsel the patients about how close their tumor may be in proximity to specific nerves to help them better inform and make a better operative decision. And then of course we also have used it in patients where we're concerned about perinatal spread of tumor but for whatever reason the patient cannot receive Galilean contrast material. Okay, so let's talk of the big use of cranial spate at goal based neurology, which is for pain syndrome. So to understand, looking for pain syndromes on MR neuropathy you have to understand what is pathologic in a nerve on MR neuropathy what constitutes brain injury or sorry nerve injury. So, I like to think of the nerves, kind of like, you think of vessels, right. So nerves are carrying information or sensory or motor to muscles nerves, etc. The same way your vessels are blood to your brain. So anything that's going to interrupt this delivery of information the same way. If you interrupt blood flow to the brain will cause damage to the end organ. And so in the case of nerves it would be muscle muscle atrophy and in the case of a vessel it would be the brain. So, you know, the whole idea is, when you have enough damage to a nerve, you get end organ damage in terms of denervation changes of the region that it's supposed to be supplying the same way you get end organ damage like a stroke. If you decrease the blood flow enough to that region of the brain. So I really like that whole analogy of, they're just delivery systems, the same way the vessels are delivery system for blood. So, the most common classification to Emma for nerve injury is a Sunderland classification. Now this is actually a pathologic classification for which we do have corresponding findings on MR neuropathy. So the class one the most mild injury on the Sunderland classification is basically it's called neuropraxia and it's basically was some injury to the myelin. It's like a nerve bruise is the way I think about it. So, in terms of like the analogy in terms of vessels is kind of like you know a crowded black right and there's damage to the endothelium right that's how we got the crowded black but you know everything else intact there's plenty of flow everything looks good. And so the nerve can show increased T2 signal. You know from a demon like being bruised, but there's no effect on the end organ the muscle because we still have plenty of, you know the equivalent of flow right it's just nerve bruise. The most common classification class two and three is when there's actual disruption of the axon itself and the myelin, but the stuff around it the perineurium the epineurium are preserved. And I like to think of that it's kind of like a dissection. So it's not now we've actually interrupted, you know, the endothelium. But everything else the media, the adventitia that's still intact. So we've got to step beyond just having you know kind of like irritation inflammation actually disrupted it. And for this we can see increased signal and increased size. And because now, you know the same way we're now starting to interrupt the flow, you know, it's not just the plaque where you actually have like a dissection that can be throwing no emboli, we will see end organ changes. We will see denervation changes in the muscle. So class four is when you actually have full disruption but only the epineurium is intact the perineurium as well as disrupted. And I like to think of this kind of like a pseudo aneurysm. Right, what is a pseudo aneurysm except you know essentially a contained rupture. And this is essentially what it is, it's a contained rupture of the nerve. So you'll actually see it vocally enlarge the same way you would see a focal enlargement with a pseudo aneurysm. And because again we're now disrupting flow right we're disrupting the flow of information we basically ruptured the nerve. And then you will see denervation in the muscle on minorography. Finally, the most serious injury is when you actually fully disrupt everything. And you basically get an end bulb neuroma. I think of this as kind of like thrombosis, you've completely closed it off right there. There's no more flow. You can see, as a result, some malaria and degeneration of the nerve distances point. And of course, because you've completely thrombosed and close it off, you will also see the denervation changes in the muscle. So let's talk a little bit about the specific nerves that we look at and the pathology that can affect them. The big one, the overwhelming one, I would say 90% of the referrals that I get for MR neuropathy are for patients with trigeminal neuralgia and facial pain syndrome. So the trigeminal nerve is a mixed sensory and motor nerve. It exits the pons and then after it goes through Meckles cave it triplicates into its three divisions V1 ophthalmic, V2 maxillary and V3 handibular. So the ophthalmic division exits the superior fissure and then branches into frontal lacrimal and nasal celio branches. So I like to remember that because what's around the orbit right this is the ophthalmic nerve right well you have your frontal bone right your forehead and along the medial aspect of your nose and on the lateral aspect of your lacrimal gland so that's your three branches frontal lacrimal and nasal ciliary. And these regions, innovate basically the orbit and the forehead, and that's where you got your sensation. So on MR neurology we can actually see these nerves. So we can actually see V1 going through the superior oral fissure. And you can see here on the images we can actually see it branching into the frontal nerve, and then the trunk that will give off the nasal ciliary and lacrimal nerve. The superior aspect of the image you can see the ocular motor nerve in this region as well. So when we're talking about pathologic processes that we're going to be looking at for view one. It's obviously a close continuity of sinus so sinus infections can possibly affect it. Again, you can see perineural spread of tumor especially for skin cancers that affect the forehead region. And it's really rare to get a schwannoma in this area. Next we have V2. V2 goes out foramen retundum and it enters the pterigopalding fossa where it gives off basically branches to the palate and the aviolus of the magsula. And then it traverses along the inferior aspect of the orbit in the infrorbital canal at the infrorbital nerve and then terminates in the skin there and basically provides sensation to the midface. So on MR neurology, we are actually able to visualize the micro anatomy of this nerve. So you can see here, we can actually identify the maxillary nerve going into the pterigopalting ganglion. You can actually see a little bit on this image, the palatine nerve extending inferiorly from that pterigopalting ganglion. We can also trace out the inferior infrorbital nerve along its entire course. It is incredibly common to see facial skin cancers have their perineural spread along the infrorbital nerve. And this is an example of one of those curved multi-planar reconstructions that you use in order to trace out the nerve over its entirety. One of the things that really made me fall in love with this technique was the amount of detail that you can see. On this, we can actually see the individual nerve to each of the teeth in the magsula. And I was showing this image actually to one of the neurosurgery fellows who works in the anatomy lab and he said to me, he was like, this is what I see, you know, and it kind of reminded me of the, you know, seen in Jurassic Park where the paleontologist finally sees like, you know, the dinosaurs come to life. It was like this. He's been working in this anatomy lab looking at these cadaver. And now he gets to see everything he has been seeing on the cadaver in real life, in real people, and able to see the pathology affecting them in life. So again, similar to v1, the maxillary nerve, close proximity to the sinuses can be impacted by sinusitis, malignancies of the hard palate. There's a lot of minor salivary glands in the hard palate that have a tendency to be things like you can have perineural spread of tumor. One of the things that we do get consulted on is if you have a fracture of the orbital floor that involves the infra-orbital canal, then you can cause injury to the infra-orbital nerve and get paracetias in that region. So looking for injuries of that nerve related to prior orbital blowout fractures. And similar to v1, it's very rare to have nerve chief tumors. Finally, the mandibular division. It provides sensory basically to the mandible, lower face, and also motor to the muscles of mastication. So it accepts out through Framon of Valley. The motor branch is actually a very small branch relative to the sensory portion of the nerve. And then it gives off the irregular temporal nerve, the lingual nerve, and then the inferior abular nerve. So the irregular temporal nerve is basically sensation around the temporal mandibular joint and ear. The lingual nerve joins with the cord of timpani to provide sensation and taste to the tongue. And then the inferior abular nerve is basically, it gives off some motor to the floor of mouth, and then it's the sensation for the gingiva and teeth of the mandible. It exits finally out the front of the mandible in the mental foramen and supplies sensation to the chin and lower lip. So we can actually see all of these branches. The trideminal v3 branch is actually the thickest branch and one of the easiest ones for us to actually be able to visualize. As you can see here on this anatomic drawing the auricular temporal going laterally, and then the inferior abular and the lingual kind of looking like to like stick man legs going down and we can actually see exactly what we see on the anatomy drawing on our MR neurology. The lingual nerve and the inferior abular nerve kind of travel in parallel with the lingual nerve going towards the tongue and the inferior abular nerve going towards the mandible, and we can actually see that kind of forped appearance that you see anatomically. We can see it also on MR neurology. So the things that can affect v3 is adontogenic affections extending into the inferior abular canal. Anything that injures the mandible can injure the inferior abular nerve and the inferior abular canal so fractures, osteodontic process. And I would have to say that one of our biggest referral basis is pain after tooth extraction due to injury of the inferior abular nerve extraction from dental procedures. And again, the gingiva is in very close contact with the mandibular aviolus and so you can definitely have involvement by malignancies in that region and it is rare to have Schwannomas. So here's some example cases. There was a young woman who had five months of kind of difficulty eating and kind of chewing with peristigias along her lower lip after a third molar tooth removal. And here you can see that the inferior aviolar nerve on the right is incredibly bright compared to the left. You can see it. It's not per se enlarged, maybe a little bit, but you can see the difference in the signal between the abnormal right side and the normal contralateral side of the nerve is only, you know, slightly lighter than the adjacent muscle. So this was a Sunderland type one injury. And this is another example. This was an elderly woman who had pain kind of over the left Cretagus and cheek after a left first mandibular molar extraction. And you can see that we did a ton of imaging over over many, many years I mean like, I think like we went down to like yeah and like 1997, all the way to like, 2018 we were imaging her she had this constant pain no one could figure it out. And we've been doing, you know, traditional MRs of the orbits and face trying to look for the source for pain, but we could never find it. So finally, when we started doing this the ENT who had been seeing her for all these years was like, oh my gosh I have the patient for you we need to look at her. You can see here that the normal inferior aviolar nerve so that normal forked appearance of the lingular nerve or the lingular nerve above it and the normal inferior aviolar nerve. On the pathologic side, you can see that you have this thickening of that proximal inferior aviolar nerve with kind of very fitting almost, it's very difficult to see actually the nerve distal to this region. And so this is essentially an end bulb neuroma and and of the inferior aviolar nerve that was causing her pain. And the video nerve so the video nerve is involved in cluster headaches in fact they used to be called video neuralgia before they got more fancy name. So one of the things is we can actually see the video nerve itself on these MR neurography images. So you can see here that the video nerve is the thin line going through the video canal right below right above it. You see that line above it that's the. So they're kind of like stacked so V2 and frame and return them and below it the video nerve, and you can actually see that on this anatomic image from a staffer, you can see the thicker V2 on top and then the very thin video nerve on the bottom but it's, it's incredibly thin but we can actually still see it with our MR neurography Okay, occipital neuralgia, we get a lot of referrals from the headache clinic for patients with occipital neuralgia. So the big nerve that we are really concerned about is the greater occipital nerve, the greater occipital nerve is actually the thickest cutaneous nerve in the entire body. It rises from T2 and basically goes along the posterior aspect of your occipit and extends over the top of your scalp providing sensation. There's also the lesser occipital nerve and the least occipital nerve but they are they're actually much more difficult to visualize by MR neurography. We can see a lot, but we can't can't quite be everything. So here is images of the greater occipital nerve. So this is just a surgical image showing it arising from that dorsal ganglion of C2 and extending posteriorly along the suboccipital muscle to rise along the scalp to provide innovation in that region. So you can see let me do like the direct coronal you can't always see it quite the entirety of the nerve. And so that's why we really do like to do here's an example of that multi planar curved reformat in order to lay that nerve out in its entirety and be able to see the entire length of the nerve and be able to compare thicknesses signal among different regions of the nerve. So the other occipital nerves can be affected by compression point from its common finding for patients with occipital neural neuralgia, and you can sometimes get occipital region lumpanopathy but that's rare unless you have a skin cancer of the scalp. Now she timbers relatively rare malignancy also rare. So in clinic they can target these with Botox. They can actually do it just by clinical palpation of landmarks. And we also can do it ourselves as radiologists using image guidance with CT or ultrasound. The important role that MR neurology plays in these patients because they already know they have occipital neural depth is being able to identify that the disease is unilateral, because if they're going to have decompressive surgery, and they only decompress one side but it's an eye lateral occipital neural the patient won't be helped. And it's very difficult to tell like if it's truly one sided or not clinically because there can be a lot of referred pain to the opposite side. One thing we can help them with is if there is continued or recurrent pain after surgery we can tell them if there's perhaps adhesions or you know muscle I've heard to be that may have caused recurrent compression and they might need another decompressive surgery. And we can also look for if they cause a post-operative neuroma on their own from post-article injury to the nerve. So where does the greater occipital nerve get compressed where should you be looking for it. So the greater occipital nerve sits like a little P in a pod between the multivitus muscle and the semi spinus spinous capidus. And in between those two that sandwich right there that that that fat is where your greater occipital nerve is and where it can be compressed. So what we are looking for when we're doing MR neurology of the nerve is oftentimes we may not see the compression it can be somewhat positional related to the muscle position. So we can look and try to see if there is a difference between the two nerves and make sure that that there is asymmetry to confirm unilateral disease. So you can see here that on the patient's right, it looks fat and thickens right and it's got a little hot belly on us right it's a very thick and nerve where compared to the very thin normal side. So we can tell them that yes, there is asymmetry. It looks like it is unilateral disease and that will give them confidence that a unilateral decompression will be enough to help this patient. So I'd like to end on what we're really trying to push and use this MR neurology for which is preoperative planning for our skull based surgeons for skull based tumors in particular. We also want to use it for our ENT surgeon for parotid surgery. So the facial nerve is the Achilles heel of parotid surgery and injury to it can be relatively devastating to the patient in terms of quality of life. And it's the reason that a lot of times you know we don't want to do anything percutaneous in the product because we're afraid of hurting the facial nerve. So the facial nerve is predominantly for the muscles of facial expression it comes out the style of mastoid frame and it then gives off the auricula temporal nerve, and then branches into its two major branches the temporal facial find the temporal and facial region and the cervical facial which is the lower facial region. So we can actually see the branching. So if you look here at the top image you can see, you can actually trace the facial nerve as it comes down out of the style of mastoid frame and it makes an abrupt turn to give off that temporal facial branch, and then lower down, it gives off the cervical facial branch as well. So these then divide into what we traditionally remember as the branches of the facial nerve the temporal zygomatic buckle margin manager and cervical. We all remember from med school to Zanzibar by motor car rate it's it's one of the few at that school is still useful rate. And you know you ain't using the club cycle anymore so it's good that something you memorize in medical school is going to be helpful to you. And we can see each of these individual branches, and not only can we see the branches we can see the branches of the branches. So here you can see this trifrification here of the zygomatic nerve along the zygomatic arch and male our eminence. And here you can see this very distal bifurcation of another branch of the zygomatic portion of the facial nerve. Here you can see the buckle nerve, and you can see here the same pitch fork, trifrification that you can see on the anatomic images you can also visualize on the MR neurology itself. So we are able to visualize the incredibly distal portions of these branches the facial nerve. So no matter how peripheral your lesion isn't the product. We can see what facial nerve branches are near or what facial nerve branches possibly involving the most commonly injured branch of the facial nerve in product surgery is the marginal mandibular branch. You know it's it's kind of a forgotten branch except when it gets injured and we can actually visualize it it's incredibly small compared to like the zygomatic portion, we can still visualize it and even visualize it individual branches as well. So the big thing for the facial nerve is obviously the product, product injury from product surgery and then of course the products themselves may also involve it and have perineural spread of tumor. The lower cranial nerves for skull based tumor removal is also what we want to be able to apply this technique more to. We can actually see the incredibly complex anatomy at the skull based, both the vascular anatomy and the cranial nerve and anatomy that is in that region of the regular brain in particular. So you can see here we can actually see the glossopharyngeal nerve, and we can actually trace it along the styloid process, especially in patients have ego syndrome but again, it's an important nerve to be able to identify when they're doing surgery at the at the particular region of the regular frame and we can visualize the vagus nerve as well. The biggest number is much larger a little bit easier to visualize than the glossopharyngeal nerve, and not only can we identify the vagus nerve itself. We can actually see its individual branches. After the vagus exits the side of the regular frame and it gives off the auricular branch going posteriorly we can actually see this as well and then trace the vagus nerve down through the school base. I'll tell you that we have tried to trace the recurrent varyngeal nerve we did for that. It's actually quite difficult just due to the respiratory motion, but at the school base we can visualize the vagus with extremely good accuracy. You can also visualize the hypoglossal nerve. You can see here this is where it's exiting through the hypoglossal foramen, and where it swings around to join the lower cranial nerves and the carotid space before moving anteriorly to the tongue. So you can see we can take it all the way on our curved multi-planar reformats from the hypoglossal canal out along around through the carotid space as it turns and now it's going to be going kind of out of plane here into the tongue itself. We can actually even visualize the sympathetics in this region. So we can actually identify the superior cervical ganglion in this region, which is important because we talk about all these named nerves and we're all concerned about the cranial nerve, but there can also be a lot of morbidity resulting from damage to the superior cervical ganglion. And hopefully maybe, you know, as this technique becomes more commonly used and more commonly understood, this is the type of thing that we can look for when patients have a horn or syndrome, you know, can we actually visualize the cervical ganglion and damage to that region. So this is the thing that I just absolutely love being able to look at these images and feel like I'm looking at an anatomy textbook, you know, and being able to see these structures that I've always learned were there, but had always had to infer pathology with them, but now I can actually see them and identify pathology in them. We can even visualize the accessory nerve. This is incredibly important because the most common cause of damage to the accessory nerve is from percutaneous lymph node biopsies. So if we are able to help the interventionalist by pre-procedurally telling them where the accessory nerve is in relation to what they want to biopsy, that can potentially help save a lot of unnecessary iatrogenic injury to this nerve. Additionally, one of the biggest causes of morbidity after a radical neck or even a modified neck dissection is injury to that accessory nerve and getting that kind of shoulder sag from the damage to the trapezius. So if we can better tell the surgeon ahead of time whether or not a sacrifice of the accessory nerve is necessary, is there involvement of the accessory nerve by the lymphadenopathy? That might help them to kind of, if there's no involvement, be very clear, very clear away from that region and possibly avoid further injury in that region. So thank you so much for coming to my talk. I am so incredible honored to be here. I just wanted to thank Zee King Lee. He was one of the MR physicists who really helped us to get this sequence off the ground. So here's my school-based surgeon, collaborator Andrew Little and Griffin Tantarelli and John Milligan who are the ENTs who have invested a lot in both getting me patients and giving me clinical feedback about the accuracy of this technique. So they've all really helped to bring this to the clinical forefront. Okay, thank you very much. Thank you so much for sharing your lecture with us. If anyone has any questions, please put them in that Q&A box and we'll try to get through as many as we can before our hour is up. We've got a couple here that I'll toss out to you, Dr. Anahali. First, in class one Cinderland classification, are there T2 changes in the muscle or the nerve only or both? So Cinderland class, the type one, as I said, it's kind of like a nerve bruise, right? Like if someone punched you in the face but they didn't break anything, right? So you'll recover. You still can have your modeling career ahead of you if you get punched in the face with just the black eye, right? They didn't hit your zygomatic arch, it didn't fracture, you know, you still have your beautiful teeth bones and everything. And that's the way I think of Cinderland type one injury. So there aren't muscle changes. So when you start to see any sort of muscle changes, you should be concerned that it's above a class one type of injury. Any chance to assess CN4? So we are not really able to visualize CN4 very well. It's an incredibly tiny nerve. We can see it intracranially and we can see it along the course of the intracranial portion along the tentaurium, but we have difficulty visualizing it in the orbit. And it hasn't really been a big push for us because A, it tends not to result in, you know, like a facial pain syndrome that we tend to get these referrals for because it's a motor nerve. And then the injuries to cranial nerve or tend to be intracranial along the tentaurium from that, you know, crossing on it from the tentaurium. So it tends not to have pathology that's beyond the skull base. It tends to be more of an intracranial type of pathology. So we haven't really had requests for cranial nerve for and we do have difficulty visualizing it consistently. We did actually, I'll tell you, we did a cadaver. And if you have someone laying that still for that amount of time, we did a third cadaver head. You can see it, but it's more difficult in true clinical scenarios. What recommendations can you give if we are trying to achieve these results on a 1.5 Tesla? I have to be honest with you. I don't think it's, it would work. I think that the scan times would be too long for the patients to be able to tolerate it to be able to get the resolution that you need. And I think you'd have a lot of motion artifact. So I would, I would just say that if you're going to do this type of imaging, you really need a 3T to be able to feel confident in your diagnosis. There's a lot of artifacts that can make it very difficult to tell if like a nerve is truly injured or if it's motion. So you really need to have high quality images to be able to perform this well. This might be related to that last one. How can we perform the reverse fiesta sequence on a 1.5 Tesla MRI? So you definitely, you definitely can. The problem is that you're just not going to be able to get the spatial resolution to get, you know, that 0.5 millimeter isotropic coverage to get the entirety of the, you know, basically the skull base and then you have to extend it through the face as well for these nerves. And the time would be extremely long. And it's difficult for patients to hold still. And because we're imaging things that are so tiny, little bit of motion can make it very difficult. You know, it's not a easy sequence to simply, you know, pull out of a box and do I'm going to be honest with you like that's why my, my, my acknowledgments include our, you know, MR physicists, why we were scanning, you know, sever cadavered heads. There, there is, you do have to have a certain level of quality assurance. You do need a three T, and you do need the patient holding still. And you do need to be able to do this multiplayer curve reform up. I often do neck biopsy and FNC. What is the percentage of injury to accessory nerve by doing FNC or biopsy. So, so, so it turns out to be, you know, really the a, if you're a radiologist, it turns out to be the radiologists who are doing a lot of the accessory nerve damage. And it's usually tends to, you know, we're usually right in lymph node, it usually comes to be people who are doing it percutaneously by palpation, who may not be quite as accurate. Certainly the FNA needles, the size of them are not usually associated with accessory nerve injury, it's usually when we're coring those those and unfortunately sometimes you do need the core you know they you can't get a diagnosis just based on the FNA sometimes. All right, next one. I understand you acquire a T two stir image and a black blood sequence to create these images do you do a subtraction of these sequences in order to create the final product. The final stir is actually is a T two fat shot with a with it with it with a black blood and it is all it's all one sequence so for so so that's the sequence that we do for the Braille Hill excess and it's actually on Phillips it's called nerve use so it's a T two with black full a T two fat with black blood so it's not a subtraction image. It's all part of one acquisition. I'll avoid talking about spins and pulses and things like that and but there's never a few to help anybody but yeah it's all one it's all one package. Um, great. I think this question says can you add in small coils. Does that make sense. I mean, can you can you do it on like a 16 or an eight channel head coil, you can. And the time is going to be a little bit longer and also the 32 channel head coil this has better superficial image quality so that's why we like to do the 32 head channel coil but but you can do it and initially. We, we, when we were trying to set this, this, we were doing it with both. I thought the image quality was better with 32, but, but you can do it with with lesser and get pretty good image quality. Which machine do, do you use is it Siemens three T. No, these are all these are all actually a Phillips engineer. But I have to say that I think Siemens has incredible image quality and I'm sure that the that you can get, you know, certainly equivalent, and not better quality. Awesome. Well there's one more question. I'm curious any advice for new new neuro radiology fellows and training. Read as much as you can. And, you know, I feel like the nothing, nothing makes you a better radiologist than just seeing as much as possible. There is no such thing as a wasted study, even those negative studies that you're annoyed with on call that the ER sending you, they are teaching your brain. What's normal and every time you go through them that's reinforcing your brain. What's normal that the abnormal stuff will start to pop out to you. So, there is no better advice that I give to any radiologist new old, you know about to retire the more you read the better you are so so it's all about I think as much volume as you can. Thank you so much for answering all those questions and thank you for your lecture today and for everyone else for being here and asking those questions. You can access the recording of today's conference and all our previous new conferences by creating a free online online account. Join us next week, Thursday, April 13 at 12pm featuring Dr Francis ding for a case review live on head CT profusion cases. You can register for this free lecture and we're on. Follow us on social media for future conferences. Thanks again and have a great day.