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This is an MRI of the brain

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in a one-and-a-half year-old child

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with tuberous sclerosis complex.

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We can see multifocal areas of cortical dysplasia.

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We can see subependymal nodules.

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We see this area in the anterior aspect of

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the right putamen, a signal abnormality that's

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centrally hyperintense on T1-weighted imaging.

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That is a finding that can be associated

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with tuberous sclerosis complex, likely in

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the same spectrum as areas of dysplasia.

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There are multiple subependymal nodules.

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And it's important to note, actually, that these

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subependymal nodules themselves are not tubers.

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These are not what the tubers are.

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The tubers are the areas of cortical dysplasia.

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They're these subependymal nodules,

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this lesion in the right putamen.

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Now, this patient ended up having

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seizures that were not fully able

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to be controlled with medications.

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And I'm going to show you, this is

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what her corpus callosum looked like.

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Her seizures were not able to

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be controlled by medications.

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But they result in the patient falling

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or having what's called drop attacks.

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If a patient falls and has drop attacks, they

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have the potential of hurting themselves.

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For a seizure to do that, it has to generalize

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and go to both cerebral hemispheres.

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So this patient underwent what's

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called a corpus callosotomy.

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Where the corpus callosum was transected at

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the midline here approximately 80 percent of

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it was transected, and the splenium were spared.

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So, while this may not fully stop the

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seizures, it may stop the drop attacks.

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For instance, if a seizure starts

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in the right cerebral hemisphere.

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The corpus callosotomy will prevent or

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decrease the likelihood of it propagating

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to the left cerebral hemisphere.

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If the left cerebral hemisphere is not

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involved by the seizure, the patient will

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retain control of the right side of the body.

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If the left hemisphere and the right side of the

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body remain in control, then the patient will

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not typically fall, or if they do fall, they at

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least have one extremity they can use to grab

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onto something or to brace themselves from a

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fall and decrease their ability to get hurt.

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Now, evaluating the corpus callosotomy is

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a time where we can use advanced imaging

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to help us understand what's going on.

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It both helps us understand

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what's going on in this patient.

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And also, since we have an idea of what's

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going on with this patient, it helps

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us understand the advanced imaging.

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This is a directionally encoded fractional

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anisotropy map from diffusion tensor imaging.

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In this, the convention is that green

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means fibers that are going anterior and

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posteriorly, such as the optic radiations here.

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Blue are going into the plane or along the

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z-axis, such as the descending fibers of

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the corticospinal tract in the posterior

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limb of the internal capsule here.

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And red are transversely oriented fibers,

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such as these commissural fibers within

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the splenium of the corpus callosum.

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So we can see we're not seeing any red

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along the remainder of the portions of the

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expected location of the corpus callosum

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because there has been transection with

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the corpus callosotomy, whereas we see

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preservation of fibers traversing the splenium.

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This is diffusion tensor fiber tracking,

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sometimes referred to as tractography

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showing the forceps major remains intact.

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These commissural fibers extending from one

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occipital lobe to the other remain intact.

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The corpus callosum has what's

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called homotopic commissural fibers.

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So a given place in the right occipital

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lobe connects to the equivalent

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place in the left occipital lobe.

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But if we look here, looking at the

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deep white matter of the frontal and

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the parietal lobes, using that as a seed

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for the diffusion tensor fiber tracking.

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We do not see any commissure fibers traversing

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the midline through the corpus callosum.

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See, it stays in the ipsilateral hemisphere.

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Similar here, it stays in that hemisphere and

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same with anteriorly with the forceps minor.

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going to the genu of the corpus

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callosum, but stopping at the

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midline, stopping in the midline.

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So this is a way of using advanced

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imaging to confirm the surgical outcomes,

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but also using the surgical procedure

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where we can understand what was done

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to better understand what the advanced

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imaging means and what it can be used for.

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So this is a patient with tuberous sclerosis

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complex with drop attacks where they

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had a near-complete corpus callosotomy.