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So now we're going to talk about Susac syndrome.

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It's a retinocochlear cerebral arteriopathy,

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and there's a clinical triad: encephalopathy, which may

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include personality change or paranoia,

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bilateral hearing loss,

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and branch retinal artery occlusion.

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So usually, they come in with visual changes,

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hearing loss, and encephalopathy, and sometimes

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other focal neurologic deficits.

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The imaging is similar to MS,

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except the lesions tend to be transcallosal,

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and they can involve gray matter.

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So here, images of a 21-year-old female who have

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headaches, numbness, tinnitus, and vision changes.

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And you can see she's got this extensive white matter

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abnormality involving the internal capsules,

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extensive multifocal lesions in the corpus

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callosum, and some subcortical lesions.

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Some of the foci have restricted diffusion,

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suggesting acute infarcts.

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Some are going to be a little more chronic, and you

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can see when you look at the sagittal FLAIR

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weighted images, these transcallosal lesions.

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Usually, multiple sclerosis has lesions on

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the undersurface of the corpus callosum.

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And they also don't tend to have a lot of edema.

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They're microinfarctions,

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but there's no demyelination.

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Now, I'm going to show you a case of Susac syndrome.

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These are images of a 52-year-old female with

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migraines, vertigo, hearing loss, and a

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branch retinal artery occlusion.

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These are the DWI images and the ADC images.

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As we go through them, you can start to see tiny

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little infarctions in the bilateral temporal lobes.

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You know they're acute because they're bright on DWI and

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they're dark on ADC images, and they predominantly

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in the white matter,

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although there are some deep gray matter lesions

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as you can see in the thalami and the

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lentiform nucleus on the left.

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And there are also lesions in the corpus callosum.

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Multiple lesions in the corpus callosum, and again,

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numerous other white matter lesions,

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as well as some small cortical lesions.

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And then, let's show you the FLAIR images.

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You can see better on the FLAIR images.

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There are also some older cerebellar

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lesions that aren't bright on DWI.

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And again, white matter deep gray nuclei lesions.

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A few more on the FLAIR images that you don't see

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on the DWI just because they're more chronic lesions.

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I also have some coronal FLAIR images.

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Let me show you those.

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These are post-contrast, and you can see on the

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coronal FLAIR images that there are some

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areas of leptomeningeal enhancement.

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You can see hyperintensity in multiple sulci

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consistent with leptomeningeal enhancement.

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Again, you can see multifocal white matter lesions,

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as well as some lesions in the corpus callosum.

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So, let's make sure there're no vascular abnormalities.

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So we'll take a look at the Circle of Willis,

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and you can see that the Circle of Willis looks normal,

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the MCAs, the ACAs,

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the bilateral posterior cerebral arteries,

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that all look normal, and we'll just

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flip it in the other direction.

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You can see the ICAs here.

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So normal vessels, multiple deep gray nuclei,

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and white matter lesions,

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and then the lesions involve the corpus callosum,

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and the patient has branch retinal artery occlusion and

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hearing loss, and those are hallmarks

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of Susac syndrome.