 Okay, so this is a young woman who was being evaluated for a follow-up of known multiple sclerosis. When I look at the scans for multiple sclerosis, I generally have up initially the axial flare scan, the axial T2-weighted scan, and the axial diffusion-weighted scan. And what I do is I generally scroll through these in order to identify the demyelidating plaques in the axial plane initially. As I mentioned, on T2-weighted scanning, demyelidating plaques are better seen in the infertentorial area. So initially we're going to look at the cerebellum and the brainstem on the T2-weighted scan focusing. And then as we shift to the supertentorial space, the flare scan becomes the dominant, most accurate way of evaluating because of the Virkel-Robas space, perivascular space issue, as described previously. Initially I will also have the diffusion-weighted scan up to look and see whether there is active demyelination with cytotoxic edema and also to exclude another entity such as a stroke that could potentially be simulating multiple sclerosis. So here we go. We're going to focus initially on the axial T2-weighted scanning. So pretty early on we are seeing multiple white matter lesions that are coursing through the brainstem, as well as affecting the middle cerebellar peduncle, which is the main tract that connects the pons to the cerebellum. And we are also seeing more peripheral white matter lesions in the left side of the cerebellum. Again, these cerebellar white matter lesions may be better seen on this T2-weighted scan than looking at the flare scan to the left here. So these are the demyelination plaques in the brainstem as well as in the cerebellum. As we course more superiorly, we see that there is diffuse involvement of the left side of the brainstem and the midbrain. And now as we enter the supertentorial space, my eyes are going to shift a little bit more to the flare imaging because, as I said, tends to show the demyelination plaques in a better fashion because CSF1 T2-weighted scan is the same signal intensity as the demyelinating plaques. So let's just look at these relatively quickly here. We have a large area of demyelination in the spleenium of the corpus callosum. We have white matter lesions that are subcortical or juxtacortical. And we have demyelination, which is occurring in a periventricular region. When we talk about the McDonald criteria for multiple sclerosis, we have to look at four different locations. Number one, juxtacortical demyelination. Number two, periventricular demyelination. Number three, infertentorial demyelination in the brainstem and cerebellum. And finally, in the spinal cord. If two or more areas are involved, then it satisfies the McDonald criteria for dissemination in space within the central nervous system. So if you look at, for example, this area of demyelination in the subcortical white matter of the left frontal lobe, seen on the flare image, you can see how that might be mistaken for CSF space on a T2-weighted scan, which is why flare is generally relied on most in the supertentorial region. Now, currently we're on the B0 map on the diffusion-weighted imaging. And I will just scroll around until we get to the B1000 images, which is here, to look for areas that are bright in signal intensity. And we would have to correlate that with the ADC map in order to determine whether or not there actually is restricted diffusion or whether this is merely T2 shine-through. So remember, on the ADC map, T2 shine-through is bright in signal intensity, whereas active cytotoxic edema is going to be dark in signal intensity. So if I stop on this image, what we see on flare image is a demyelinating plaque. On the DWI, we see it as bright in signal intensity. However, on the ADC map in the middle, we see that there actually is a small area of dark signal intensity in the periphery, which might suggest that this has cytotoxic edema and therefore is more likely to be active plaque. Now, we will also look at the gadolinium-enhanced sequences to make that distinction. But this is what we're looking for on the ADC map combined with the diffusion-weighted scan. All of the other demyelinating plaques are just bright in signal intensity without dark signal. Down here, we're just seeing some artifact in the left lateral temporal lobe. I'm going to pull down now the T1-weighted scans to show whether or not the demyelination is showing contrast enhancement indicating active blood-brain barrier breakdown. So as we scroll, we see that much of what is seen in the brainstem and cerebellum is not showing contrast enhancement. However, as we get further superior, we come across a lesion in the left coronary radiata, which is showing bright signal intensity enhancement on the T1-weighted scan post gadolinium. And you note that based on all the other flare demyelinating plaques, there's no way for us to know that this one versus this one versus this one is going to show contrast enhancement. However, when we do the T1 post gad, we are noting that this plaque seems to be an active plaque by virtue of its enhancement. You might want to correlate that with the coronal scan and it verifies the contrast enhancement in that left-sided plaque. So on the coronal flare, what we're seeing is this lesion here, which corresponded to the more peripheral enhancement on the left side. On this same coronal image, we see that there are going to be, as we go further superior, additional plaques that are showing contrast enhancement. So let's scroll up a little bit more superior and we're starting to see some of these plaques that did indeed show gadolinium enhancement on the T1-weighted scan as well as peripheral and arcs of enhancement on the coronal scan. I want to just focus on this coronal scan for just a moment because it demonstrates the different types of enhancement of demyelinating plaques. You can have open arcs of enhancement. You can have a peripheral complete rim of enhancement. And as you can see in this subcortical demyelinating plaque, you can have solid enhancement. So multiple sclerosis plaques show a wide variety of contrast-enhancing patterns, including solid nodular peripheral complete rim, open rim enhancement, and linear enhancement, which is how I would characterize this demyelinating plaque. I want to just show the sagittal flare scan. So after I've looked in the axial plane, which is my comfort zone, I also look at the sagittal flare scan. The sagittal flare scan shows the midline structures optimally. Here we have the midline structures, including the corpus callosum, and we see this large area of demyelination in the spleenium of the corpus callosum. You also note the brainstem involvement, as well as some areas of cerebellar involvement on the sagittal flare image. One of the areas that you want to look at closely is what's called the colossal septal interface. The colossal septal interface, obviously, is that interface between the corpus callosum and the septum polysum. And it's this area right here. We look at this area for focal areas of demyelination because that is relatively specific for multiple sclerosis. Actually, not identified in this particular case, but it's relatively specific for multiple sclerosis and allows us for the differential diagnosis of demyelinating disorders. This patient also had susceptibility-weighted images performed, and you might get a sense here of the central vein identified in some of the plaques with the perivenular demyelination indicative of multiple sclerosis. Finally, we should look at the cervical spine that was also included, and the typical MS protocol includes sagittal and axial scans through the cervical thoracic spine. We don't have to do the lumbar spine because, obviously, the spinal cord generally ends at around L1. So let's look at the scans through the cervical spine. And I will usually put up the T2-wayed scan, the T1-wayed scan, and the stir scan. And what one sees in scrolling through these is an area of bright signal intensity within the spinal cord at the C4-5 level. This is on the sagittal scan. We're going to confirm this on the axial scan. You also note another area of peripheral cord-high signal intensity at the C2-3 level. When we bring down the sagittal post-gadolinium enhanced scan and compare it to the pre-gadolinium enhanced scan, we are able to define whether or not these plaques are going to show contrast enhancement. Now let's look at the axial scans. So when I'm looking at the axial scans, I usually will have either the T2-wayed scan or the stir image available in sagittal plane as I scroll through the axials. As you can see here, the patient was moving, not the best study. However, when we get down to where that large plaque was, we can see that it was affecting the right side of the spinal cord. So here's the demyelinating plaque at that C4-5 level. Here is the bright signal intensity in the spinal cord on the FASPINECO motion degraded scan. And here it is on the gradient echo scan. Sometimes it's better on the gradient echo. Sometimes it's better on the FASPINECO, but I think you should include both sequences in the axial plane just for the cervical spine. For the thoracic spine, we only do axial T2-wayed scan with FASPINECO technique. If we pull down the post-gadolinium enhanced scan, we are actually able to see quite nicely better on the axial scan than on the sagittal scan that this is indeed a demyelinating plaque that's showing contrast enhancement. So it's in the periphery of the spinal cord, not centrally, but in the periphery of the spinal cord you see that area of active demyelination demonstrated by gadolinium enhancement. I want to finish this case, which is actually a quite illustrative case with one other pearl from Dave Yusam. And that is usually the only thing that is performed in the coronal plane is post-gadolinium enhanced scan. You can reconstruct the sagittal flare scans into coronal planes, but the one that is performed only in the coronal plane is usually post-gadolinium enhanced coronal images. This is the sequence that I look for, demyelination or enhancement in the optic nerves. Optic neuritis is one of the manifestations of multiple sclerosis. Usually because the sections are too thick in the axial plane, we usually don't see the optic nerves that well on axial scans in the multiple sclerosis protocol. However, you get a chance to see enhancement in the optic nerves to suggest active optic neuritis on your coronal post-gadolinium enhanced scan. This is done for the brain, so we're looking at all the plaques here and we're looking at the plaques. But take the time to slow down at the level of the optic chiasm and then follow the optic nerves into the orbits to see whether they are showing contrast enhancement. And in this case, this is the optic nerve on the right side, which is showing mild enhancement on its undersurface on the coronal image and the pre-chiasmal right optic nerve. You see it's actually somewhat enlarged here. So let me just highlight that with my pen. So this is the optic chiasm on the left side. Here on the right side, we're at the junction between the pre-chiasmal optic nerve and the optic chiasm. And you're seeing that it's enlarged and on its periphery, we are actually seeing a little bit of contrast enhancement. So this patient also appears to have active demyelination in the optic nerve suggestive of right-sided optic neuritis. So lengthy description, but a great illustrative example of the different manifestations of multiple sclerosis.