Get a Group Membership for your Organization. Free Trial
Pricing
Free TrialLogin

Chiari II with Interdigitation of gyri

HIDE
PrevNext

0:00

This is an MRI of a 13-month-old child with

0:04

a known lumbosacral meningomyelocele.

0:07

And we know that a lumbosacral meningomyelocele

0:10

has essentially a 100% association with an

0:14

intracranial Chiari type II malformation.

0:16

So,

0:17

this MRI, sagittal T1-weighted image, shows

0:21

we see a vertically oriented,

0:25

very small in caliber fourth ventricle.

0:27

We see an abnormal appearance of the cerebellar

0:30

vermis and cerebellar ectopia,

0:33

which includes the cerebellar tonsils

0:35

and the cerebellar vermis.

0:36

We will confirm that on the axial images,

0:39

you can see

0:41

cerebellar tonsils and the cerebellar vermis

0:44

extending down into an enlarged foramen magnum.

0:50

We're seeing several other features.

0:51

We're seeing a large massa intermedia.

0:55

We're seeing somewhat of a beaked appearance or

0:59

posteriorly pointing appearance of the tectal plate

1:02

related to a more horizontal appearance

1:05

and configuration of the inferior colliculi.

1:09

Now,

1:10

every patient with Chiari type II malformation

1:12

is a little bit different.

1:14

This patient,

1:15

the corpus callosum, doesn't look too abnormal.

1:19

We're seeing somewhat truncation of the

1:21

rostrum of the corpus callosum,

1:23

but the genu and the body of the

1:25

corpus callosum are normal.

1:26

We have the physiologic thinning of the isthmus,

1:29

and we have the splenium of the corpus callosum.

1:32

The corpus callosum may be slightly

1:33

smaller than usual,

1:34

but this is not as abnormal as we sometimes see.

1:38

Here,

1:38

we see what may be an interhypothalamic adhesion.

1:43

This is a finding that has been seen slightly

1:46

more commonly in the setting of a

1:48

Chiari Type II malformation.

1:49

Notice other adjacent structures.

1:52

There's the massa intermedia.

1:54

There is the anterior commissure,

1:55

the optic chiasm.

1:57

But this structure right here,

2:00

just posterior to the lamina terminalis,

2:03

might be an interhypothalamic adhesion.

2:07

If we look on this Chiari type II malformation,

2:10

we can see there's a ventriculoscopy catheter

2:13

in place because there's a near 100% association

2:17

of Chiari Type II malformation with hydrocephalus.

2:21

Now, with the ventriculoscopy catheter in place,

2:24

the ventricles are now normal in size,

2:26

so it's doing its job.

2:28

But we see another interesting finding that's

2:32

characteristic of Chiari type II malformations.

2:35

We see interdigitation of gyri

2:37

across the interhemispheric fissure.

2:39

This is felt to be related to fenestration

2:41

of the falx cerebri.

2:43

And in this case,

2:45

you actually could even see this finding

2:49

on this coronal head ultrasound

2:53

at one month of life.

2:56

So, we're seeing interdigitation of gyri in the

3:00

setting of a Chiari Type II malformation with

3:03

the characteristic posterior fossa and

3:06

supratentorial abnormalities.

Report

Description

Faculty

Asim F Choudhri, MD

Chief, Pediatric Neuroradiology

Le Bonheur Children's Hospital

Tags

Spine

Pediatrics

Neuroradiology

Musculoskeletal (MSK)

MRI

Idiopathic

Congenital

Brain

© 2024 MRI Online. All Rights Reserved.

Contact UsTerms of UsePrivacy Policy