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This was a young woman who was in a motor vehicle collision

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and presented with neck pain and headache

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after the motor vehicle collision,

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patient had a brief episode of loss of consciousness.

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The initial CT scan, as I show it, is unremarkable.

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No evidence of hemorrhage, no evidence of hydrocephalus,

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no evidence of extra-axial collections.

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And since we are focused right now on dissections and clots,

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we look at the intracranial vessels and we don't

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see any hyperdense vessels in the brain.

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The patient had bone windows which were also negative

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because of the patient's neck pain.

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The patient also had a cervical spine CT scan at

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the same setting and this too was negative.

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Shortly thereafter,

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the patient developed some element of dysmetria apparent on

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physical examination during the time

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within the emergency room visit.

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Because of the new neurologic symptoms and

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the persistence of left-sided neck pain,

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the patient had an MRI scan as well as an MRA of the neck.

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So let's look at that next.

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This is the flare scan of the patient's brain and

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on initial view of it, it looked pretty good.

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However, as you can see, in the posterior fossa,

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one has a small area of high signal intensity seen

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in the posterior portion of the cerebellum.

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And in the inferior lateral left side of the cerebellum,

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there seems to be an area of hyperintensity.

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On flare imaging,

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the diffusion-weighted scan was next

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performed and as you can see,

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there is a small area of high signal intensity in the

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lateral aspect of the left side of the cerebellum.

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Now,

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this is an area where one has susceptibility artifact

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at the air-bone interface and brain-bone interface.

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So this hyperintensity around the periphery

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of the cerebellum is normal.

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However,

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this was a more focal area of high signal intensity that was

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worrisome for potential early stroke and was also

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seen on the flare imaging.

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For this reason,

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the patient proceeded to MRA of

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the neck as well as the brain.

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I'm going to show the maximum intensity projection

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images from the left side of the vasculature.

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This is the internal carotid artery on the left side

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arising from the aorta. And as you can see,

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the bifurcation looks good and there

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are no dramatic areas of contour.

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Or luminal abnormality. However,

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within the left vertebral artery.

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To identify this,

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you see the left subclavian artery and the

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origin of the left vertebral artery.

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The left vertebral artery as one ascends one comes to

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this area of marked dilatation of the blood vessel,

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a pseudoaneurysm and distal to the pseudoaneurysm you

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can see that there is an area of vascular narrowing.

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Let me see whether I can magnify this a

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little bit for you all.

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There we go.

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So pseudoaneurysm with distal area of narrowing and in

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point of fact proximal to the pseudoaneurysm

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you see a small area of narrowing as well.

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And this is from

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the MRA of the neck.

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One thing that I will recommend when looking for dissected

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blood vessels you should do a spin echo fat-suppressed

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T1-weighted scan to look for clots in the vessel.

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Remember that high signal intensity clot will be obscured by

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adjacent fat if you do not apply a fat suppression

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technique in order to see clots in the vessel.

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On Spin-echo imaging.

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What I generally like to do with my cases in which I'm

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concerned about dissection is take the raw data here from

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the Gadolinium-enhanced MRA and create a multiplanar

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reconstruction in the axial plane.

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And that way you can see the blood vessel in cross-section

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in order to define whether or not there is clot in the

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wall or whether there is a focal area of dilatation.

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As you can see in this case,

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we have a dramatic change in the caliber of the blood vessel

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on cross-sectional imaging representing the pseudoaneurysm.

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So as I said previously,

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dissections and pseudoaneurysms of blood vessels are much

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more common in the neck after trauma than intracranially.

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And this is a good example of a vertebral artery dissection

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defined by the narrowing of the blood vessel proximal

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and distal to an area of pseudoaneurysm.

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Why do I say pseudoaneurysm?

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This is because the wall of the blood

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vessel has been traumatized.

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This, depending on whether or not the patient is having neurologic

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symptoms or demonstrating that this

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is a source of thromboembolism.

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The patients may be treated either conservatively with

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medical management or if the patient is

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throwing clots and having strokes,

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more likely the patient will be treated with stenting.