Case: Childhood Stroke, Moyamoya on CT
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I did want to show the CTA on the child who
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had a watershed infarctions bilaterally,
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worse on the right side than the left side.
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Here is that CTA.
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So as we come up from below, we see good
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images of the internal carotid arteries,
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as well as the vertebral arteries.
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In this situation, we're most concerned about
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the internal carotid arteries because it was
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the watershed of the anterior circulation.
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We see that the internal carotid artery
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on the left side is slightly smaller compared to
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the internal carotid artery on the right side.
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And the petrous portion of the internal
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carotid artery is symmetric from side to side.
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Here we come into the cavernous internal
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carotid arteries, and we do notice a difference
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in the size of the left cavernous internal
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carotid artery compared with the right.
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And then, continuing further superiorly, we lose
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the entirety of the cavernous carotid arteries
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bilaterally as we come to the paraclinoid portion.
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So where are the blood vessels here?
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There aren't blood vessels.
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They come back in here, but they've
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obviously got areas of narrowing.
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Here is a very narrowed and attenuated M1 segment of
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the middle cerebral artery and A1 segment of the
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anterior cerebral artery and distal left internal carotid artery.
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On the right side, we follow it up, and it too shows
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not such great enhancement right at the distal tip of
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the right internal carotid artery and the A1 segment.
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We're, we're missing this segment right here.
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So, as I said, I tend to like looking at
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the MIP image in the coronal plane to better
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evaluate the distal internal carotid arteries.
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Here are the ACAs, which look pretty good.
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And here we have, I'm gonna
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magnify this just a little bit.
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If we zoom in, we see the attenuated,
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narrowed paraclinoid—this is the clinoid
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process—internal carotid artery on the left.
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We see the narrowed internal carotid artery on
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the right side with areas of stenosis in the
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proximal A1 and proximal M1 segments bilaterally.
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And this prominence to the lenticulostriate
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branches is what is known as moyamoya.
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Moyamoya in Japanese means "puff of smoke."
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And it represents the collateral vessels
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of the lenticulostriates, which feed into
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the distal middle cerebral artery branches.
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So this patient has distal internal carotid
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artery narrowing with proximal A1 and M1 stenosis
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bilaterally, a little worse on the left side
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than on the right side, with associated
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moyamoya phenomenon of the lenticulostriates.
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Because this is a bilateral process, we would say
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it's more likely to represent moyamoya disease.
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If it was a unilateral process and due to a secondary
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phenomenon, we use the term moyamoya syndrome.
David M Yousem, MD, MBA
Professor of Radiology, Vice Chairman and Associate Dean
Johns Hopkins University
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