Thank you for joining us for the case-based review course in neuroradiology at RSNA 2020. I am the course director, Amy Giuliano. On behalf of the RSNA Educational Committee and our track chair, Dr. Ricardo Restrepo of Nicklaus Children's Hospital in Miami, welcome to the session. For this second of our two sessions, we have a focus on adult neuroradiology as well as interventional neuroradiology. I am delighted to introduce our distinguished faculty, Dr. Nickerson of Oregon Health and Science University, Dr. Amrine of Duke University, Dr. Glastonbury of UCSF, and Dr. Milburn of Ochsner Medical Center in New Orleans. As a reminder, both these neuro sessions are available on demand until April 30th, 2021. And now let's get it started. Welcome to our adult brain case-based review session here at RSNA 2020. My name is Joshua Nickerson, I am the division chief of neuroradiology at Oregon Health Sciences University in Portland, Oregon. And my topic for today is I think neuron to something. Thank you very much to Amy Giuliano for the invitation to give this series of cases and for coming up with that exceedingly witty title for my talk. I don't have any relevant financial disclosures for this presentation. The format for today's presentation is going to be unknown cases. I'm going to show you a series of images. And then since we can't be particularly interactive this year with this format, what I'm then going to do is show you a GIF image, which is a hint to the diagnosis. I've seen this format making the rounds on Twitter and other social medias, and I think it's actually kind of a fun way to discuss the case. Then I will show you the diagnosis and we'll go over some relevant points about each of the entities. So without wasting any more time, let's jump into case number one. So this is a 37-year-old man who was found down with persistent altered mental status and he got an MRI. On the top, you can see some axial flare imaging and on the bottom are the post-gatilineum T1 weighted sequences. On the first image, you can see there's some flare hyper-intensity in the periaqueductal regions. Moving along, you have more flare hyper-intensity in the region of the hypothalamus involving the mammillary bodies. And as we move more superiorly, there's signal abnormality in the thalamides, a fairly bilateral and symmetric appearance, which is a hint to the category of diagnosis you should be thinking about. When we look at the post-gatilineum imaging, you can see that in the ventral periaqueductal region, we have a little bit of enhancement. Similarly, there's some symmetric enhancement in the hypothalamus and mammillary bodies. And on the post-gatilineum imaging more superiorly, you see that there is a little bit of enhancement in the medial thalami as well. So here is your hint as you should be thinking about what the potential diagnosis is here. And indeed, this is Wernicke's encephalopathy. So anytime you see that pattern of symmetric and bilateral abnormality, you should be thinking about something toxic or metabolic. As in this case, this is a disease caused by a deficiency of thiamine or vitamin B1. These patients typically will present with confusion and ataxia. And frequently, these are alcoholic patients, although not always. There are other entities that can cause Wernicke encephalopathy. What you're going to see is exactly what we see in this case. This is a fairly classic presentation. Mammillary body abnormality, thalamus, periaqueductal gray matter can involve the tectum as well. But when you see that symmetric and bilateral appearance, you should be thinking about something metabolic. It may enhance, may also restrict diffusion in the acute setting. So let's move on to another case. This is case number two. This is a 61-year-old woman. She has progressive headache. And we have a series of MR images. So the first is a T1 axial. Across the top, we then have a gradient. There's a T2. And then we have a couple of post-catilineum images below and a diffusion-weighted imaging. Right away, you can see there's a mass. It seems to be centered within the fourth ventricle. On the gradient imaging, you can see there is some susceptibility artifact associated with the periphery of the mass, which you can also see on the T2-weighted imaging. You can see some CSF outlining portions of the mass. So it looks like it probably is an extra axial process. And then on the post-catilineum imaging, you can see that there's a fair bit of homogeneous and fairly avid enhancement. On the diffusion-weighted imaging, there is very little, if any, diffusion restriction. So here is your hint for this patient. And why do we drink milk? Well, aside from maybe thinking it's delicious, we drink milk to get calcium. And that is what the susceptibility artifact in this patient turned out to be. And this turned out to be a fourth ventricular meningioma. This is a pretty interesting case in that this is an uncommon location for these tumors. First of all, intraventricular is an uncommon location. But when these tumors are intraventricular, they're most more commonly in the supratentorial atria of the lateral ventricle. For some reason, people like to talk about it being slightly more common in the left atrium than the right. But fourth ventricle is certainly uncommon. When you see that susceptibility artifact, you might be thinking that could be blood, could also be calcium in the appropriate valence of calcium. These tumors often enhance avidly. That's fairly typical. And you're used to seeing these sort of as extra axial tumors more commonly in the supratentorial space. But they are going to have very similar signal characteristics, even if they are intraventricular. The key to making the diagnosis is really that this is not a very common location or age group for other tumors that occur in the fourth ventricle, whether you're thinking about choroid plexus tumors, ependymomas. These would be pretty unusual in a patient of this age and wouldn't typically have calcifications associated with them. You might be thinking about getting a CT to look for that calcium. But this turned out to be a meningioma. All right, let's move on to another unknown case. This one is hot off the press. I actually just read this case last weekend on call. This was a 65-year-old woman who came in with progressive weakness and multiple falls. And I'm giving you three different axial MR images. On the left, you have an axial T2, in the middle you have an axial flare, and finally you have an axial T1, where I've made a measurement, which should be a bit of a hint for the diagnosis here. On the T2 imaging, you have marked volume loss involving the middle cerebellar peduncles. And you also have this fairly characteristic cruciform T2 hyperintensity in the pons. You can see there's extensive cerebellar volume loss, which is easy to see on both the axial T2-weighted images. And then when I show you the T1 image, what I've measured there is the diameter of the middle cerebellar pinnacle. As you can see, it's measuring 6.2 millimeters. So here comes your hint for this case. Yes, it's hot dogs, which is maybe not the traditional form of this issue. So this is multisystem atrophy, and this is quite an advanced-looking case. This is an adult-onset neurodegenerative disorder. Can be divided clinically into two different types of presentations, one with predominantly cerebellar symptoms and another with more Parkinsonism features. The hot cross bun sign is the characteristic finding in this case. This is that cruciform T2 hyperintensity in the central pons. This is not always present. When it is, it makes for a really nice presentation case in a conference setting like this or on an exam. But it may not always be there, even if multisystem atrophy is the diagnosis. What we do see more commonly and more specifically is this middle cerebellar peduncle atrophy. The middle cerebellar peduncle should measure about 10 millimeters or more in a normal patient. When you see it measuring less than that in the axial plane, you can start to think about this diagnosis. Here these are measuring 6 millimeters, well below the normal limits. This is a fairly sensitive finding. And often we'll see global cerebellar atrophy, although that is obviously not particularly specific and can be seen in a number of other entities. All right, let's move on to another unknown case. Another hot off the press case, as I saw just a couple of weeks ago in clinical practice. This is a 57-year-old man with tremors and a little bit more clinical history, which I'm not going to give you, as that would clearly give away the diagnosis. So across the top, I'm giving you three diffusion-weighted images, and at the bottom, two somewhat motion-degraded flare images, which go along with the patient's tremors, which he was unable to control. On the diffusion-weighted imaging, I'll just tell you the ADC maps match this finding was with hypo-intensity in the regions of bright signal on the DWI imaging. We see abnormal signal, looks like it's involving some cortex, probably that's the region of the pre-central gyrus, but also some cortex of the frontal and parietal lobes within the inter-hemispheric fissure. Looking a little lower, we see that there's some asymmetric diffusion signal in the caudate nucleus, as well as multiple foci involving the cortex posteriorly, and then more inferiorly, more cortical signal abnormality involving occipital cortex, probably portions of temporal cortex. When we look at the flare imaging, even though it is degraded by motion, there is very little, if any, signal abnormality in these regions. Predominantly, this is a diffusion-weighted signal abnormality with not a lot of correlate on all their sequences. I'll tell you this patient got gadolinium, there was no enhancement associated with these areas. Here is your hint for this case. Although this is not a direct hint for this particular entity, but it is certainly the class of entities. This is cortex-feldjakob disease. This is a rare disease, and yes, it is not the same thing as MAD-CAL or variant CJD. This patient was sporadic CJD. The incidence is one in a million, so this is a rare disease, but you will see it if you practice enough neuroradiology. This is a progressive and invariably fatal disease, unfortunately, most commonly seen in the sporadic setting, although about 5% to 10% of cases may be familial. What you see are signal changes throughout the cortex, basal ganglia, and thalamus. Diffusion-weighted imaging is going to be the most sensitive sequence for this finding. You may also see flare signal changes, but the most sensitive is going to be diffusion. Is there a differential for when you see diffusion restriction in the cortex? Of course, there's always a differential for everything. In the appropriate clinical setting, this is most frequently going to be seen in the setting of a seizure, and that may be a transient signal abnormality that would resolve a few days after the seizure activity. Mitochondrial disorders can also cause diffusion restriction in the cortex, although that's usually going to be a different age range and a very different clinical presentation. And then autoimmune encephalitis may cause diffusion restriction in the cortex, usually going to be accompanied by some flare signal changes, and in that setting, you may also see some enhancement. There are rare cases of chronic venous stasis as the result of venous thrombus giving cortical diffusion restriction, but in the appropriate clinical setting, as in this case where the patient also had rapidly progressive dementia, which is the bit of history I chose not to give you prior to giving you the diagnosis, you should definitely think about CJD. All right, let's move on to another case. This is a 38-year-old woman presented with seizures, giving you lots of images here. We have a couple of different levels of post-catalytic T1, a couple of axial T2s, some diffusion-weighted imaging, and then a couple of gradient sequences at the end on the far right. So there are a couple of areas of signal abnormality here, right? We have some peripherally enhancing nodular abnormality in the parietal lobe. Looks like there's a fair bit of surrounding basogenic edema. And then there's another focus sort of at the posterior edge of the temporal lobe, which is also showing nodular irregular enhancement, a little bit less edema. On the diffusion-weighted imaging, not a ton of diffusion restriction, certainly not seeing any endocystic components in either setting. And then on the gradient imaging, both areas demonstrate susceptibility artifact. In fact, maybe even with a little bit of a fluid level developing on that upper image, which suggests the presence of hemorrhage. So bit of a differential case, right? This could be many things. And I'm including this one just because I think it's fun in this setting to show interesting and unusual cases. But here's your hint. All right. So this turns out to be a case of pathologically proven cerebral schistosomiasis. The piece of history I didn't give you is that this patient had recently traveled to sub-Saharan Africa and had done a fair bit of walking around in the water. And that's how this disease is transmitted. So this is endemic throughout the tropics, but involvement of the brain is rare. Only about 4% of patients will develop cerebral disease in the setting of systemic schistosomiasis. Just for fun, we'll tell you that these parasites lodge themselves in the mesenteric veins, and that's where they lay eggs. The eggs are then transmitted potentially through a couple of different pathways, whether there might be shunts in the heart and can lodge themselves in the brain. There's also the possibility that the parasites directly migrate to the brain and lay their eggs there, which is just a delicious thought. And the inflammatory reaction to these eggs is variable. Some patients actually may not have much of an immune response at all and may be asymptomatic, where others will develop inflammation and can develop seizures as a result. Very similar to neurosystosarcosis. And also similar to neurosystosarcosis, the inflammatory reaction may end in a granulomatous process which can cause sort of late-stage calcifications. What is a little different than neurosystosarcosis is these patients often will have hemorrhage associated with these findings. So obviously there's a differential here. This could have been metastatic disease. It could have been neurosystosarcosis. It could have been other infectious entities. But in this case, this turns out to be cerebral schistosomiasis. So you may never see it again, but at least now you've seen one case. So this is going to be our last case. And this is a little bit more common. This is a 29-year-old man, comes in with altered mental status. The history was a little more specific than that, but I'll leave it at that for the moment. And I'm going to give you some diffusion-weighted imaging. In this case, I will give you the ADC and then an axial T2. We see a focus of bright signal on the DWI imaging, and that does appear to correspond to decreased intensity on the ADC map. And it's in a pretty specific location. It's sort of in the medial temporal lobe, specifically involving the hippocampus. If we look on the axial T2, you can see there is a small focus of corresponding T2 hyperintensity, which matches up with that. So here is your hint for this case, my favorite hint of the day. So this is transient global amnesia. And this is the very classic imaging appearance of this entity. These patients have the fairly peculiar clinical presentation of sudden onset of complete both antegrade and retrograde memory loss, which lasts for hours. And these patients have no idea who they are, where they came from, how they got to where they are. But then those symptoms will resolve and they will regain their memories. Incidence is not that uncommon, about 3 to 8 per 100,000 cases per year. And as I mentioned, this will spontaneously resolve. This has been the classic imaging appearance, a focus of diffusion restriction, very typically in the medial temporal lobe with corresponding T2 hyperintensity. And this will resolve as the patient's symptoms resolve. There are some good papers out there in the literature showing how you can use high resolution diffusion-weighted imaging to more accurately make this diagnosis and even see that it specifically involves the CA1 portion of the hippocampus. So those are our cases. I hope you enjoyed them. I hope you learned something. It's a mix of sort of the rare and interesting and maybe some entities that you will run across more commonly in clinical practice. If you have any questions, please don't hesitate to shoot me an email. My email is listed here. And I hope you enjoy the rest of this virtual RSNA. My name is Tim Amrein, and I'm an Associate Professor of Neuroradiology and the Director of Spine Intervention at Duke University Medical Center. I'd like to thank the program committee and the RSNA for the opportunity to speak to you today. Over the next 15 minutes, we'll be looking at unknown cases in adult spine. Don't worry. You're going to be just fine. I have no disclosures, although I should probably reveal that that's not actually my picture. Sorry to disappoint the audience on my first slide. Don't worry. It's all going to be downhill from here, guys. Here's our first case. This case was a patient who was found down, brought to the ED, and a CT scan of the cervical spine was performed. Bone windows to the left, soft tissue to the right. Try and make the salient findings and come up with a diagnosis. In particular, think about what you might need to say to the referring clinicians so that they can make the appropriate actions for this patient. Here's some static images from those movies to kind of point out some of the important findings. Our astute resident overnight recognized a lot of these findings and recommended an MR. The sagittal stir sequence is shown here. There's another additional and important finding here. Enter in your possible answer and diagnosis here in the chat box whenever you're ready. Hopefully many of you have recognized that this is a trauma case. Pretty bread and butter. This is a three-column fracture with an epidural hematoma. Our astute resident overnight put an ROI on this collection down the center of the canal and recognized that there's increased density here. Pounds filled units of 50 consistent with acute blood. Looking down the center of the canal is a key component to your search process for any trauma case in the spine. In addition, there's multiple fractures involving the posterior elements as well as the anterior and posterior aspect of that T1 vertebral body. On our MR, we see disruption of the ligament and flavum posteriorly and some stir hyperintensity in that T1 vertebral body. This case gives us an opportunity to talk about the three-column model proposed by Dennis. This involves the anterior column, where there's the anterior two-thirds of the vertebral body, the anterior annulus, and the anterior longitudinal ligament. The middle column, which is the posterior third of the vertebral body, the posterior annulus, and the posterior longitudinal ligament, and finally, the posterior column involving the posterior elements and the ligament and flavum. What do we see in our case? Well, there is actually involvement of all three columns. We had a fracture anteriorly in the T1 vertebral body, posteriorly here, and also involving the posterior elements as well as disruption of that ligament and flavum. So this is by definition involving all three columns. Instability is defined as injuries affecting two contiguous columns. Good job on that first case. Let's move on. Another bread and butter case. Here's some lumbar spine imaging in a patient who presents with back pain. This patient happened to have a CT in their jacket, and I'm going to show that to you. Hopefully, that's going to be helpful. Anybody have the diagnosis yet just based on the MR? If not, here's your CT. That may be helpful for some of you. Go ahead and put in your answer into the chat box. The diagnosis here is a classic case of pyogenic discitis osteomyelitis. So one of the findings that we're looking for with pyogenic discitis osteomyelitis, well, in this companion case, we see that there's T2 hyperintensity in the disc, and that's pretty classic for this diagnosis. In addition to that, though, we've got florid edema and enhancement within the adjacent vertebral body marrow. So this is a really big inflammatory process, right? We've got a lot of enhancement and edema in those adjacent vertebral bodies. We've also got end-plate irregularity and destruction of the vertebral bodies as that pyogenic infection extends into the adjacent bone. And finally, as we look at our axial imaging here, we again see that T2 hyperintensity in the disc. Probably more importantly, we see perivertebral extension of this process into the adjacent psoas muscle, something that's going to clue us into infection and help us not favor something like run-of-the-mill degenerative change of the disc. What do we see on our case? Well, with our unknown case, we saw a lot of these findings, T2 hyperintensity in the disc, marked end-plate irregularity, perhaps best shown on the CT, and finally, extensive marrow edema on the STIR sequence and associated enhancement within the L5 and S1 vertebral bodies. Good job on those first two cases. Let's move on to case number three. This is a bit more challenging. We've got an axial T1-weighted image and a fat-saturated sagittal T2-weighted image. Anybody have the diagnosis just off this? Well, it's a tough case. This patient also had a CT. Let me show you what that looked like. There's one other imaging finding here that's really helpful and specific for this diagnosis. If you know what the answer is, go ahead and enter it into the chat box. What are we seeing here? Well, there's actually multiple psoas calcifications adjacent to whatever this process is in the spine, and that's a pretty specific finding for this diagnosis. In addition, if I pull back up that sagittal T2-weighted image, we see that we've got a large perispinal process that's involving multiple vertebral bodies. However, there's relative sparing in the disc, which we're even seeing on the CT. Those two findings in conjunction help us come up with the diagnosis of tuberculosis involvement of the spine, or POTS. TB lacks the proteolytic enzymes necessary to erode into the disc, and for that reason, you end up seeing an appearance as shown here. I'm going to start with a little didactic slide first for this next case. Here's an example of an epidural abscess in the spine. Epidural abscesses in the spine exhibit a lot of the characteristics that we expect for an abscess elsewhere, T2 hyperintensity and extensive peripheral enhancement as shown in this dorsal epidural abscess. Now, why did I spend my time showing you that? Because for case number four, now that you've seen an abscess and a hematoma in the epidural space, I want to ask you, which one is this? Is it an abscess or a hematoma? I'm giving you an axial and a sagittal post-contrast T1-weighted image. Anybody know what it is? Go ahead and enter in your answers. Actually, the correct answer here is show me the rest of the imaging, because if we move forward with that and I show you our pre-contrast T1-weighted image, we actually find out that that's not actually peripheral enhancement consistent with an abscess, but rather intrinsic T1 hyperintensity, which is suggestive of subacute blood products and methemoglobin and helps us come up with a diagnosis of hematoma. The T2-weighted imaging shows markedly reduced density, which is also consistent with that diagnosis. So rather than this being an abscess, this is an epidural hematoma. Often differentiating these collections on MR requires evaluation and interrogation of all of the sequences available to you. Great job on those first four cases. This one's a lot tougher. I actually have it on good authority that our moderator, Amy Giuliato, will buy anyone who gets this correct North Carolina Barbecue. So make sure to enter your answers into that chat box. Here we've got a sagittal space sequence and axial reformats. There's some findings here. Some of you may be able to make the diagnosis straight away. But it is a tough case, so I'm going to give you some additional imaging. We went into the patient's jacket. Unfortunately, they also had a lateral radiograph and a CT angiogram with an axial slice shown here at the level of C1. Hopefully some of you got the diagnosis so far. But let me point out some of the important findings. First, on our STIR sequence, we see extensive prevertebral edema. However, the discs and vertebral bodies are normal. And that's going to be an important finding here. Finally, the real key is to note that there's amorphous calcification in the region of the longest coli muscles. And that, in conjunction with the other findings, helps us come up with our diagnosis for case five, calcific tendonitis of the longest coli. This is an entity that occurs to amorphous hydroxyapatite crystal deposition in the superior fibers of the longest coli muscle. It usually presents in middle-aged adults with neck pain, dysphagia, and adenophagia and sometimes reduced range of motion. The white blood cell count in ESR can be elevated, so people will think that there might be an infection. However, that edema in the prevertebral space often does not have peripheral enhancement, so it helps to distinguish from things like retropharyngeal abscess. Importantly, also, there's no destruction of the bone and there's no involvement of the discs. So this is not disceitis osteomyelitis. This diagnosis, calcific tendonitis of the longest coli, is treated with NSAIDs and usually resolved in a few weeks. And so the treatment is markedly different from those other two entities. So you can be a real hero here reading this case correctly. Let's move on to case number six. I'm going to take you back to some more bread-and-butter spine. Here's a classic example of this entity. We've got a sagittal image and also an axial image. First I want to ask you what the diagnosis is. I think many of you will get this. Go ahead and enter that whenever you're ready. But equally important in making the diagnosis, I'd like to know, how would you were to report specifically? What's going on in this case? Well, in this diagram here, we're seeing that there is herniation of disc material beyond the edge of the vertebral body or the vertebral hypothesis, which is outlined in red there. In addition, we're seeing that in the sagittal plane. What's important to note here is that the disc material that's extended far beyond the vertebral hypothesis is much wider than that at the neck. And so B is greater than A. This really looks like a mushroom. And that is consistent with a disc extrusion, which is our answer for case number six. Remember, with disc extrusions, by definition, B is greater than A. A great reference for understanding the nomenclature for lumbar disc degenerative change can be found below. Here's another example of an extruded disc. I can show this companion case here on the right, because a lot of times, the extruded disc material is different in intensity from that of the parent disc. And that can be because there's edema or hemorrhage within that disc. Sometimes disc extrusions, as they come out, can detach from the parent disc, and there's a subset of extrusion called a sequestration or free fragment. Free fragments can migrate cranially, caudally, or either to the left or to the right. Identifying the location of them is extremely important to the surgeon, and should be specifically reported in the report. Here's examples of sequestrations in two different patients. This one's located along the midline posterior to the L4 vertebral body. However, this one's in the foramen. It's this type that I see my trainees miss most often. It can be really subtle to see, especially when it's adjacent to the nerve root. Removing the sequestration is important. It's kind of similar to having a pebble in your shoe. It's going to be uncomfortable until the surgeon goes in and gets it. Here's case number seven. This is a 60-year-old male who presented with slowly progressive lower extremity weakness and paresthesias. Shown here is an axial T2-weighted image, STIR sequence in the middle, and fat-saturated post-contrast T1-weighted image on the right. There are a couple important findings here that may allow some of you to make the diagnosis straight away. For those of you that are struggling, let me provide you some of the thoracic imaging. Some of those key characteristics are shown to even better advantage on these sequences. Anybody have the diagnosis yet? Well, this is a dural AV fistula. I have another question for you. What's the next step in management? What we need to do next is take the patient to the angiogram. So that's what we did. This patient was taken to the angiosuite, and selective catheterization of a thoracic segmental artery revealed early venous filling and retrograde contrast uptake into engorged and redundant radiculomedullary veins, confirming the diagnosis of a spinal dural AV fistula. What did we see on our diagnostic imaging to clue us into this diagnosis? Increased signal on the T2 in the region of the gray matter, and on our sagittal imaging, we see multiple flow voids here in the subarachnoid space due to those arterialized pressure and engorged venous structures. That leads to basically venous edema due to absence of outflow from the cord. We actually see those flow voids pretty well on the post-contrast imaging as well. A differential is provided here for increased signal in the gray matter of the cord. That does include spinal dural AV fistulas, but also infarct. Infarct is going to present much more acutely than this entity, which is more slowly progressive. Here's case number eight. This is a middle-aged female with intractable nausea and transverse myelitis. Anybody have a diagnosis just based on these images alone? Well, let me walk through them with you. First, on our sagittal T2-weighted image, we've got long-segment T2 hyperintensity in the cord. On our post-contrast imaging, we also see long-segment enhancement. This is greater than three virtual bodies, which helps us to distinguish it from demyelinating processes such as MS, which are usually less than two vertebral bodies in length. I think most helpful, though, is the central enhancement in the cord shown here on our axial imaging. That provides a differential that's much more narrow in scope, including neuromyelitis optica spectrum disorder, ADEM, and other systemic inflammatory infectious processes. One other clue to this diagnosis was that there was flare hyperintensity and involvement in the area post-tremor here, as well as in the third ventricle, just like this. And that can lead the areopostrema to intractable nausea, vomiting, or hiccups, as was shown in our patient. So this diagnosis is neuromyelitis optica spectrum disorder. It usually presents in middle-aged patients, more commonly female, is often associated with optic neuritis, and is due to Aquaporin-4 antibodies. Aquaporin-4 is a water channel that's located on the astrocytes of the CNS and explains why there's a predilection for the imaging findings in the circumventricular organs in this process, including the periaqueductal gray, areopostrema, and the central cord around that central canal. Let's move on to case number nine. Here's our final case of the day. We've got similar imaging appearance to that last case, sagittal T2, post-contrast T1, post-contrast T1, and axial T2. Anybody have the diagnosis yet? Well, what do we see? Here, again, long segment T2 hyperintensity in the cord and long segment enhancement, just like in our last case. But I think the clue to the diagnosis is actually on the axial imaging. Here, we're seeing enhancement that's peripheral and centripetal along the margins of the cord. And this is a really characteristic pattern that's highly suggestive of the diagnosis here, sarcoidosis. So that's what case number nine was, sarcoid. Congrats to those of you who got it. Here's a companion case showing a lot of the similar imaging findings. Again, long segment enhancement in T2 hyperintensity, and that's centripetal pattern of enhancement on the periphery of the cord. This patient had a PET CT also, demonstrating FDG ability in hyaluronid nodes, clinching the diagnosis. You guys did a great job. You were tested and emerged victorious. Thanks so much for your time and all of your attention. I'm Christine Glessenbury, and welcome to the RSNA 2020 Interactive Case Session. It's not gonna be quite as interactive as we had originally planned, but let's see how we go. Here's my disclosures. So Amy Giuliano asked me to share some cases in the head and neck. And I wanna know how many of you, just raise your hand, if you find head and neck cases difficult. Well, you're not alone. A lot of people find head and neck cases difficult. But what we're gonna share over the next 15 minutes or so is a number of cases from anatomy through some sinonasal orbital neck masses, and some weird stuff in the head and neck to round it off at the end. So let's start with some basic skull base anatomy. And I'm gonna give you the undersurface of the 3D rendering of the skull base. And just take a look at A through E and see if you can work out through which of these parameter specific structures pass, the internal carotid, the facial nerve, and the third division of the fifth nerve. So if we take a look over here, this is foramen ovale. And foramen ovale is the conduit for the third division of the fifth nerve to go into the masticator space. B is foramen lacerum, which is not really a foramen because it's really filled with cartilage. But posterolateral to that is C, which is for the internal carotid artery to pass through. Now over here, between the mastoid tip and the styloid process, we have the stylo-mastoid foramen, which is where the facial nerve emerges from the skull base after passing through the temporal bone and then supplies the posterior belly, the digastric muscle, which inserts here on the digastric notch. E is just the posterior condylar canal from an emissary vein. What about the anatomy of the anterior skull base? And most of you are probably pretty comfortable with the cribriform plate, recognizing that it has both horizontal and vertical lamella, and which are divided in the middle by the crista gaili. So we have this kind of bucket of the anterior skull base. Well, what about these different structures? Can you name these structures? And we should be pretty comfortable with these. Well, the red arrow, which is kind of the interior of that bucket of the anterior skull base is the olfactory groove, which contains the olfactory bulb. Orange is the roof of the ethmoid air cells and it's a continuation of the vertical lamella with the frontal bone, which goes over the orbit and that's the fovea ethmoidalis. Now, yellow is a canal which passes through the fovea ethmoidalis or below the fovea ethmoidalis through the ethmoid air cells. And that's the anterior ethmoid canal containing anterior ethmoid vessels. The vertical bone here that we've shown you in green is the perpendicular plate of the ethmoid. And between the perpendicular plate and the vertical insertion of the middle turbinate, we have this space immediately beneath the horizontal lamella and that's the olfactory recess, which is the home of most asthesia neuroblastomas. So let's start looking at some cases and here is a teenage patient who presents with neck swelling and we have a classic midline cystic mass in the neck. You can see this is very well circumscribed lesion in the neck. And I think most of you'd be pretty comfortable saying the most common midline cystic mass in the neck is a thyroglossal duct cyst. And most of these occur at or below the hyoid bone and up to two thirds will have aberrant thyroid tissue in the wall of that cyst. And we should look for it because in this case, you can see that that aberrant tissue actually has focal calcification, which is a clue to secondary pathology in a thyroglossal duct cyst. And while it's pretty uncommon to see this, thyroid carcinomas occur in fewer than 1% of thyroglossal duct cysts, but most of them turn out to be papillary. And as with papillary arising within the thyroid gland, the primary tumor or the nodal metastasis can have calcifications. So it is something to look for. And while recurrent inflammation within the thyroglossal duct cyst can result in nodularity, which is pretty nonspecific, calcification is not expected. Well, let's move on to this teenage boy who presents with a neck mass for two months. And he actually had an ultrasound a month prior to this MRI, and you can see that it was a cystic mass. But when we look at this, you can see we have this really inflamed looking right lateral neck lesion. And when I have cystic lesions, and really when I have anything in a pediatric case, I always start with congenital lesions, then work through infections and then into tumors. So whatever this neck mass is, it looks really, really angry, like it's infected. But with the absence of fever or white cell count, it's kind of odd to think that this could be infected. And what's going on is you have an inflamed lesion in the neck here, and this is an inflamed brachial cleft cyst. So when I start with lesions, I said we start with congenital, it's not midline, so it's not gonna be a thyroglossal duct cyst, but this is going to be an inflamed brachial cleft cyst. Most brachial cleft cysts are second brachial cleft cysts, and a third brachial cleft cyst are going to be more, they're really rare first of all, but they're found in the posterior neck. But my main differential for this might be that it's a lymphatic malformation that is also inflamed. A cold abscess like a TB or scrofula is something to think about, but pretty uncommon in our practice in the U.S. anyway, and that typically looks like a clump of cystic matted nodes when it's caseating. I might include that in my differential diagnosis for completion's sake. Three months later, you can see that this is resolved, and it looks much easier to say, this is just a brachial cleft cyst. So remember that these congenital cystic lesions often become inflamed, and you know, it's the pathologist that taught me that they're really not infected, they're really just inflamed, but they can then become hot and red. But what if this patient was an adult? Well, I would really want to put neoplasm number one in the differential, so a cystic neck mass in the adult is really carcinoma until proven otherwise, but in a kid, I'm really going to start with a brachial cleft cyst. What about this? Well, this is a four month child who's presented with a left neck mass, and you can see in the same location, but on the other side of the neck, intimately related to the vessels, we have this solid lesion, T1, T2, and coronal T2 MR shows it again. Well, how would I describe this? Well, I'd say this is a well-defined left solid neck mass, intimately related to level two posterior to the submandibular gland that is kind of relatively hyper-intense on T2 and hyper-intense on T1-weighted sequences, and it actually also has this kind of mild, but homogeneous enhancement. Well, what are we going to start with? Congenital solid mass. I think of sarcomas always, and then it could be, I guess, reactive adenopathy, but one of the clues in this image here is this lesion here has exactly the same signal intensity to the thymus, and on this coronal, you can actually see that there is a strand connecting this to the thymus, and in this case, this is ectopic thymic tissue. So about 50% of all cervical thymic masses may be continuous through the mediastinal thymus by direct extension, or by connection to a vestigial remnant or a solid cord, as it is here. So most of them are left-sided, most of them are asymptomatic and need nothing done, and really, they tend to shrink by about five years of age. What about this teenage patient with one month only of sinusitis symptoms, no nosebleeds, no fever, or any other constitutional symptoms? The patient completely denies that. Well, in kids, the first thing I'm going to put on a differential diagnosis for deep face masses, and especially if they are clearly invasive, as this lesion clearly is with bone destruction on the CT, and on the MR, you can see invasion in the middle cranial fossa, the first thing on my differential is always going to be a sarcoma. But as in real life, there's always a differential diagnosis, and so after sarcoma, I would list lymphoma, nasopharyngeal carcinoma, or some really unusual sinonasal carcinoma, and there are no flow voids here for me to really put in a juvenile angiofibroma in the differential diagnosis. The problem with these sarcomas, they are very, very aggressive masses, and very invasive, as shown here, but they typically have this very short presentation, so no one's really thinking malignancy, and so when the radiologist says, you know, I've got a really aggressive lesion here, it can be really quite disconcerting to the referring person with this. The restricted appearance on diffusion is really helpful for you with this diagnosis with a solid mass, and you should feel pretty confident with an aggressive invasive mass, particularly with restricted diffusion, to come down for a high degree of concern that this is an aggressive malignancy. Of course, these are typically treated with chemo, radiation, and surgery. We typically will do MR and PET CT for this. I want to show you a companion case here of a 15-year-old presenting with nosebleeds, and of course, everybody is thinking, is this going to be an angiofibroma? But again, very aggressive, very invasive. This is an aggressive, unusual Epstein-Barr-Barr-related nasopharyngeal carcinoma as a companion case. Well, what about this patient with nasal stuffiness who is presenting with this mass in the nasal cavity and the right maxillary sinus? And so it's pretty solid, but heterogeneously enhancing mass filling the nasal cavity. Very heterogeneous T2 appearance, which we typically refer to as cerebral form. And when you see that, you should really think of an inverted papilloma. But my question to you is, why did I include a CT? And the reason I included the CT is the appearance of this focal hyperostatic bone. So that focal hyperostatic bone is very helpful for the differential diagnosis, but this cerebral form appearance on MR is pretty typical for an inverted or inverting papilloma. If you see this hyperostatic strata or wedge, it is the origin of the inverted papilloma. And finding this on CT really confirms your diagnosis for you and really helps the surgeon because they know now to cut here to resect the entire thing. And it's not uncommon to find this strata or wedge, and it can really make, it can obviously confirm your diagnosis and make it much easier for you and much easier for the surgeon for handling what to do with this. Okay, let's move into an older patient here, and this patient presents with obstruction and nosebleeds. And you can see on CT, we have this destructive lesion because we've lost that cribriform plate, the horizontal and vertical lamella, but we've also lost the laminar papilloma in this. So when you're looking at sinonasal masses, the key things are that if you see bone destruction, you need to go down a specific route. Cancer, cancer, and cancer is what you want to start with. You're going to have in your differential diagnosis, chronic inflammatory granulomatous disease, granulomatous with polyangiitis, sarcoid, cocaine granulomatosis, or in chronic invasive fungal disease. There are certain things that must be in your report. You must describe intracranial extension. You must describe whether there's any orbital extension. You then need to look at the contralateral orbit because that's obviously important for any surgical management. And then you're going to look for retropharyngeal and level two lymph nodes at the very least. You can also add into this any features that refine your differential diagnosis, but remember that radiologists are not pathologists. What we're looking at here is we're trying to give differential diagnosis features, and these can be helpful. In this case, it was sinonasal melanoma, which is a rare subtype of mucosal melanoma arising in the nasal cavity. And also is very, very poor prognosis. I said around two years. It has a tendency to recur distantly and locally and is very difficult to manage. Okay, let's move to the orbit. And what about this patient with an infiltrated mass in the left orbit? And one of the things that I want to call to your attention is that you have a mass in the orbit, but she has enophthalmos, that I is drawn in. And so when you get that in your history, the first thing I want you to think about is orbital metastasis from breast cancer, because there is this retraction of the globe that happens to be seen with sclerus tumors. She also happens to have a couple of brain metastases as well that you may have noticed on the imaging. But I want to just remind you that when you have a mass, you should have exophthalmos. This is a companion case with bilateral smooth masses in the orbit, a very rare entity, but it's the only other entity I know that when you have enophthalmos with masses, and that's this NSG, which is a non-Langerhans cell, histiocytosis, gives you enophthalmos with orbital masses. Now, the last case I'm going to show you is this patient who has a sore throat and ear pain, and you can see this smooth tissue around the carotid, but notice there is no narrowing of the internal carotid artery. We have some mild enhancement on the MR images, and this is carotidinia or Typic syndrome, transient perivascular inflammation of the carotid, a very funny name for this inflammatory process, which tends to resolve with non-steroidal anti-inflammatories. No luminal narrowing is key, and your differential is really a granulomatous or inflammatory processes, and Lund-Hodgkin's lymphoma, which also tends not to result in significant narrowing. So that's a pretty brief run-through. Thank you so much for your time and attention, and I hope to see you next year at RSNA at McCormick Place. Thanks. Hello, my name's James Milburn. I'm an interventional neuroradiologist at the Ochsner Clinic. Thank you, Amy Giuliano, for the invitation to speak today. I'm going to talk to you about catheter-to-the-rescue and solving CT and MR conundrums. For my disclosures, I'm a speaker for Penumbra, and I have been a consultant for Stryker Neurovascular, and neither relationship will affect this talk. The first case I'd like to show you was humbling, but I learned a lot, and I think you might too. So this is a 40-something-year-old woman with a subacute right MCA stroke. I was asked during the course of my day to do an angiogram, and I did. You can see her stroke on flare, and here's my angiogram. There was a little minor stenosis there, I called, at the ICA bifurcation, and intracranially, I didn't see any stenoses. So after this negative workup, unfortunately, she came in four weeks later with a large, now-completed stroke. You can see on diffusion imaging. We did another angiogram, and she shows acute clot thrombus in her ICA bulb, and the intracranial views show multiple branch occlusions that go along with her right MCA stroke. So what happened? When I look back at the CTA, which preceded my first angiogram, I saw this triangular defect in the proximal bulb posteriorly, and you can see it on my angiogram, just it's not profiled well. This is a triangular lesion that we refer to as a carotid web, very important lesion. We've been seeing these carotid web lesions for years without knowing really what they were, so it's a shelf-like filling defect in the proximal bulb. Usually doesn't cause much stenosis, but it causes turbulence with swirling of the blood, posterior and pooling of blood that eventually forms thrombi, and that can embolize or cause a big clot in the bulb. Studies have shown these in 21% of cryptogenic strokes. Black females are the most commonly affected population. They're an intimal variant of fibromuscular disease. Here's another very typical lesion, 44-year-old female, acute right MCA stroke. We can see this more broad filling defect. It's another carotid web, very common configuration. That patient presented with a distal ICA occlusion, and you can see the carotid web and the distal occlusion. We removed that with a single pass thrombectomy, and then placed a stent over that web, and the patient had a nice result, as you can see on the CT. Another patient shows the association with fibromuscular disease. Well, there's a small web, and the patient also has FMD more distally, and another patient that presented with multiple small embolic strokes. Finally, here's three other typical web patients, just to give you an idea of what they all look like. So this is just a very important thing that we need to be looking for, and you need to tell your neurologist, or neurosurgery, or neuroendovascular colleague about, because these really need to be treated one way or another. Some people are stenting, some are doing surgery, some antiplatelet regimens, or anticoagulation. Okay, let's move on to our next topic. This is a 75-year-old man who presented with multiple episodes of bilateral visual loss. So he didn't have any strokes seen on CT, but eventually went to an angiogram just to look for a treatable lesion in the posterior circulation, and he did have irregularity of that distal left vert, very hypoplastic right vert. You can see he's had surgery in the neck previously. So over the next year, this man had multiple strokes, and you can see now he really has a bad situation, multiple infarcts in his posterior circulation. So the patient was referred back to us, and we noticed that he actually had a fractured pedicle screw on the left at C1, and it looks to be impinging on the vertebral artery slightly. So we did an angiogram, and in the neutral position, he does have a little intimal irregularity in that vertebral artery, but then when we turn his head, we see that flow actually stops right at that pedicle screw where it's impinging. So this is a classic Bowhunter's syndrome. Well, it's actually not a classic. It's an iatrogenic Bowhunter's syndrome, so a little different than the usual. Bowhunter's syndrome is positional occlusion or stenosis of the vertebral artery leading to vertebral basilar insufficiency. It usually occurs at C1, C2, and you can often see stenosis on the initial imaging, but then when you turn your head, you get reduction in flow in that vertebral artery. So you really require bilateral disease to have this become insufficient flow, and we diagnosed this with provocative angiography. Here's a companion case. The patient has severe facetarthropathy at C2, 3 on the left, and you can see narrowing of the foramen transverse serum. So on the left side, you can see the neutral angiogram. Right vertebral artery is smaller. Left vertebral artery is the dominant, and with patients turning the head to the right, nothing really happened, but turning the head to the left, you can see that he's developed this high-grade stenosis, impeding forward flow. Finally, a Magda view showing those same images unsubtracted where you can see the stenosis, and that's the corresponding CT image at that site. So moving on from Bowhunters to another topic. So the next patient was transferred to us from an outside hospital. Patient had chronic sinus infections and prior surgery. Rheumatoid arthritis on immunosuppressive medications. Was also diabetic. He had prior surgery. You can see on imaging, there was a peripheral process and abnormality at the skull base, and the patient already had a left parietal infarct. On CT angiogram, we can see a fluid collection below the skull base on the left, and there's erosion of the bone and the skull base involving the carotid canal. The ICA, the petrous ICA looks small and irregular, and there's a pseudoaneurysm extending inferiorly from the horizontal petrous ICA. The patient was brought to our hospital for management by ENT. So on the morning of this procedure, they went in and attempted a biopsy and drainage, but all they got was frank blood through the wound, and the patient got packed and brought to me for angiogram. So on my angiogram, I can see that some narrowing of the distal ICA and proximal cavernous portion from involvement or spasm, and the patient has a large pseudoaneurysm projecting inferiorly as we could see on that prior CTA. So I went ahead and did a balloon occlusion test. The patient was under anesthesia, so I did an angiographic evaluation. You can inject the opposite side and just kind of watch right to left flow and see how fast it runs through the left hemisphere. You can't really test the patient clinically very well. And then I went ahead and did a carotid sacrifice, and he did well from all of that, and left the hospital. Patient came back to my attention at four weeks because I started to have some left hemisphere intermittent symptoms. We did an angiogram and saw that the patient had developed a stenosis and is right now. So unfortunately, this skull base osteomyelitis had spread to the right side. So they continued and changed the antibiotics, and we're treating for fungus as well. But at 10 weeks, it actually just continued to get worse. And eventually, I did a gentle angioplasty and improved flow, improved symptoms for a while, but did not do well in the end. So in the last case, we had a skull base osteomyelitis with abscess eroding the left carotid, producing pseudoaneurysm, which I had to treat with sacrifice. But despite that, it continued and affected the right side. So I have a companion case. This is a child below one year, has a large retropharyngeal abscess that has been treated with multiple drainages. CT with contrast shows that the patient has a pseudoaneurysm. This young child had a large MRSA retropharyngeal abscess. What you're looking at now is a CT angiogram that shows the carotid as it enters and exits on the top right of the screen, this large pseudoaneurysm. And the ICA distal is small. Eventually, the infection was successfully treated and the abscess resolved. Unfortunately, the patient still had this large pseudoaneurysm. My neurosurgical partner, Dr. Aaron Dumont, performed this angio and treatment, decided to place a flow diverter over the lesion. If the lesion is not infected, you can place a stent. But on the previous case, it was infected, so that's why we had to sacrifice. Treatment was a little challenging, had to circle through the aneurysm to find the outflow, as you can see on that road map image on the right. So treatment was successful using a flow diverter. And here's, you can see the final result. Our final patient was transferred following biopsy of a left middle ear mass, which resulted in massive arterial hemorrhage. The patient was packed and sent to us for emergent management. On the CT scan, we can see a soft tissue attenuation mass within the middle ear, contiguous to the lateral extent of the carotid canal, which appears narrowed. Angiography of the right and left carotid are shown here. On both sides, there's an abnormal appearance of the carotid circulation. Both carotids appear small and taper as they approach the middle ear, where there's a more lateral and angulated course. On the left, there's also a little irregularity from the recent biopsy. So I elected to sacrifice this abnormal section that had been previously biopsied and hemorrhaged. So I performed a balloon occlusion test, occluded the left, injected the right, showed good flow, and the patient passed clinically. And then I went ahead and sacrificed this segment with coils. And after that, interestingly, on the follow-up, the patient still had patency of a collateral pathway from other branches of the ascending pharyngeal artery, which anastomosed to the medial petrous segment. ECIC pathways are plentiful in the ascending pharyngeal artery family. Abarent ICA is a rare disease. Bilateral abarent ICA is even more rare. This can cause hearing loss, pulse synchronous tinnitus on otoscopy. There's a retrotympanic red mass that can mimic a paraganglioma. Neuroradiologist's job is to identify this so that the patient does not receive a biopsy as in this patient, which can be catastrophic. The abarent ICA is failure of formation of the extracranial ICA with a hypertrophied collateral pathway developing. The inferior tympanic artery is a branch of the ascending pharyngeal artery, and this hypertrophies and anastomoses with the carotid tympanic artery at the genu of the petrous ICA. In summary, today we discussed the importance of identifying carotid webs as an important and common cause of cryptogenic stroke, Bowhunter syndrome, carotid artery-infected pseudoaneurysms, and the abarent ICA. Thank you all for your attention.

neuroradiology

Wernicke's encephalopathy

multisystem atrophy

epidural hematoma

sinonasal carcinoma

inverted papillomas

carotid web

angiography

imaging techniques