Case - MR Perfusion Target Mismatch (Poor Collaterals)
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These are images of a 71-year-old male
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who had right-sided hemiparesis.
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This is the non-contrast CT.
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You can see the dense MCA vessel sign.
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There's some hypodensity in the insula
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and the basal ganglia.
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Cortex doesn't look too bad.
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Maybe a little bit in cortex.
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On CTA,
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this is just the MIP,
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you can see top of the ICA
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going into MCA lesion,
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and there's pretty bad collateralization.
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So, almost malignant collaterals in that area.
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So, we got an MR and diffusion-weighted images
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show a pretty big infarct
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involving the anterior temporal lobe, the insula,
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basal ganglia, and the frontal lobe.
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And when we look at the perfusion images
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together with the diffusion images, we can see,
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so these are the Tmax maps,
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you can see there is a mismatch here.
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There is tissue at risk.
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There's quite a bit of tissue at risk
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in the left temporal lobe,
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where you don't see any DWI abnormality,
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and then there's some risk in the parietal lobe.
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This is artifact back here.
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So, this is a core penumbra mismatched.
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It's just that the core is already over 70 CCs,
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and the patient has malignant collaterals,
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and the infarct is growing really fast.
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So the patient's unlikely to
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do well with thrombolysis.
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You might spare some tissue,
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but the infarct's growing so fast,
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it might be hard to spare that.
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So, large infarct core
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with a core penumbra mismatch.
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This patient did not go to thrombolysis.
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Here's the follow-up.
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So, here's the initial DWI on the top
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and the follow-up on the bottom.
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And you can see that area that was at risk
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on the perfusion maps,
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now is infarcted.
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So basically,
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it extended into the mismatched area.
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You can see the same thing at the vertex.
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So, this is an example of a large core
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with a core penumbra mismatch
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but had malignant collateral
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so it was growing too fast.
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Did not go to thrombolysis,
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and the infarct extended.
Pamela W Schaefer, MD, FACR
Professor of Radiology, Vice Chair of Education
Massachusetts General Hospital
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