Case - Comparison of MRA vs CTA in Acute Stroke Imaging
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Today I'm gonna show you a
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comparison of MRA to CTA.
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These are images of a 76-year-old male
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with aphasia who presented with a facial
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droop, and this is the non-contrast CT.
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And you can see a hyperdense right
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MCA, and not too much else on the CT.
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Really can't see ischemia.
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They got a whole CTA, and carotid
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in the neck looked pretty normal.
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Here's a bifurcation, a little plaque,
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not too exciting, maybe mild narrowing.
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Follow the carotid up, there's a little
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loop in the neck, and we'll follow it up,
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little atherognomous calcification in the
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siphon, and here's the cutoff right where
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we saw the hyperdense vessel sign, and then.
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Pretty decent collaterals, actually.
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This patient was difficult to image.
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And then we can just show you the MIP images.
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There's the cutoff.
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Maybe intermediate collaterals,
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not the best study.
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As we said, there were some
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limitations in imaging this patient.
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So the patient arrived here, got
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an MRI a couple of hours later.
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Here's the DWI.
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There's a small infarct
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in the lentiform nucleus.
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involving the caudate body
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and the corona radiata.
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Look at the FLAIR images.
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Not much FLAIR abnormality, suggesting there's
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no breakdown of the blood-brain barrier.
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There are hyperintense vessels in
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the Sylvian fissure, suggesting that
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the collaterals are pretty good.
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We can take a look at the gradient echo.
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The gradient echo nicely shows the
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location of the plaque with the blooming.
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No evidence of hemorrhagic transformation,
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um, as you wouldn't expect in this case.
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And so we got a time-of-flight MRA of the neck.
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What you can see here is the raw
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data, and we'll follow the ICA up,
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and then you can see the cutoff there.
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You cannot determine collaterals on a time
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of flight MRA, they're slow flow, they'll
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just get saturated out, so you really
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don't know what the collaterals are based
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on this, but you can see the cutoff.
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And we also got an MRA of the neck,
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gadolinium-enhanced MRA of the neck, and we can
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look at that, and just like the CTA, when we
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follow the common carotid artery up, minimal
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narrowing at the ICA origin from the plaque, a
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loop in the neck, and then we'll just follow it
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up, and curves around, and here's the cutoff.
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And as we go up higher, we can see that
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there are pretty good collaterals here.
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We can make that a little bit thicker images.
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And you can see they're pretty good collaterals.
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So really, this is confirming that MRA and
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gradient echo are just as good as CTA at
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identifying the proximal vessel occlusion.
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This patient had a very low NIH Stroke
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Scale and did not go to thrombolysis and
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did well, and his impact didn't extend.
Pamela W Schaefer, MD, FACR
Professor of Radiology, Vice Chair of Education
Massachusetts General Hospital
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