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This is an MRI in a three-year-old child

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with seizures and developmental delay.

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We can see a lot of aspects of the

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cerebral hemispheres look normal.

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But as we go inferiorly in the posterior aspect

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of the right temporal lobe

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and the right occipital lobe,

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we see a very abnormal appearance of the cortex.

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We don't see a normal sulcation pattern,

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and we also don't see normal white matter.

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At this age,

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the white matter should be relatively

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hypointense on T2-weighted imaging,

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as we see here on the left,

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but we're not seeing that on the right.

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On sagittal T1-weighted imaging,

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we're seeing a very irregular sulcation pattern.

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Some areas of polymicrogyria,

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but that doesn't tell the whole picture.

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If we go to a thin section,

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axial T1-weighted image,

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we see small areas of gray matter heterotopia

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within the deep white matter.

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We see gray matter heterotopia along the

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margins of the lateral ventricle,

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which is subependymal heterotopia.

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This here,

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where it's heterotopia

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that's not within the subependymal region,

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but in the white matter,

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it's called subcortical heterotopia.

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So, this patient has multifocal areas of

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subependymal and subcortical heterotopia,

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some overlying polymicrogyria,

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involving, as we can see here,

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is the posterior aspect of the lateral surface

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of the right temporal lobe,

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extending posteriorly

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to the right occipital lobe.