Collagen Vascular Diseases Overview - Examples of FMD, Carotid Web
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So now, we'll talk a little bit about
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collagen vascular diseases.
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The most common is fibromuscular dysplasia.
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It's seen in young Caucasian females.
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Pathologically,
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there are rings of fibrous tissue and smooth muscle.
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And so, what you get is a string of beads.
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And here's an example of a patient who has this
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string of beads appearance throughout her right
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cervical ICA to the left or extent
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in the left cervical ICA.
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And this is another patient who
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has left cervical ICA beading.
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So, that's what the classic spring
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of beads appearance looks like.
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25% to 30% of patients with FMD,
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systemic FMD, like they have it in their kidneys,
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also have intracranial FMD.
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Of the patients who have intracranial FMD,
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95% involve the ICA,
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and 12% to 40% involve the vertebral artery.
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It's very common to have it more in one vessel.
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And FMD is responsible for 15% of spontaneous
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cervical carotid dissections.
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So, carotid web is thought to be a variant of FMD.
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And on pathologies, there's thickened intimal
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fibrous tissue that projects into the lumen.
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This is seen in middle-aged patients who have
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recurrent strokes.
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And this is what you see,
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you see a thin linear filling defect in the
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posterior wall of the carotid bulb.
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It looks exactly like that
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on reconstructed images.
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And you have to be really careful when you're
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looking at axial images because you'll see,
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you know, basically, the normal common,
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and then you...
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common carotid,
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and then you just see this in the proximal internal.
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You see on two images.
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Remember, you're looking at 1000 images.
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So, when you're looking at the bifurcating,
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you have to go through it slowly.
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This is a classic carotid web.
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And the patient had an MCA embolus,
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as you can see on this MIP reconstruction,
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and had a small MCA stroke
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involving the right lentiform nucleus.
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So, remember to look closely at the carotid bulb
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when you're looking at your images
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because this can be easily missed.
Pamela W Schaefer, MD, FACR
Professor of Radiology, Vice Chair of Education
Massachusetts General Hospital
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