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I Want To Know How That Is Not Considered Chiari

Posted on 4 days ago

Question: They said all of her scans are normal. I want to know how that is not considered chiari. I also would like to know why her odontoid bone looks like that. I’ve been told it’s normal but I can’t find anything that shows it being pointy as normal. Also, her c1 on the right side (left in image) looks weird. She fell and landed on the back of her head and crunched her neck on concrete. She started having all these issues since then and I feel like they are overlooking things. She also most likely has EDS and we are working on getting her evaluated. I feel like there might be crowding that was missed as well.

Answered by Dr. Vivek Chail (18 hours later)

Brief Answer:
No cerebellar tonsillar herniation and basilar invagination of the odontoid

Detailed Answer:
Hi,
Thanks for writing in to us.

I appreciate your interest on the matter of basilar invagination and tonsillar herniation in the MRI scan images of your daughter, who has had a recent fall and associated symptoms.

We draw the McRae line to make a diagnosis of Chiari malformation.

As per literature and practice McRae line is a radiographic line drawn on a lateral skull radiograph or on a midsagittal section of CT or MRI that connects the anterior and posterior margins of the foramen magnum (basion to opisthion).

If the tip of cerebellar tonsil is more than 5 mm below the McRae line then it is a cerebellar herniation.
If the odontoid crosses the McRae line then it is basilar invagination.

The lines drawn by you are not McRae lines and therefore there is no real cerebellar tonsillar herniation and basilar invagination.

The odontoid process is still developing and might be the reason for the particular appearance.

There are no features of craniovertbral junction injury.

Regards,

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Vivek Chail (1 hour later)

Is it that it’s just not the 5mm and that’s why? From the image online comparing to hers, it might just be that it’s not “long enough” from conventional standards? She is 13 and I can’t find anything about odontoid process looking like that at 13. No one can seem to tell me what it is exactly. I don’t understand. How it’s not some sort of fracture, especially when there are lines through the top on other images too.

Answered by Dr. Vivek Chail (2 hours later)

Brief Answer:
Measurements are important for a low lying cerebellar tonsil

Detailed Answer:
Hi,
Thanks for writing in to us.

The measurements are important and need to be done in the mid sagittal plane and up to 5 mm tonsillar descent is normal.

The odontoid process is still not well developed and what you see are the small bone elements and there are ligaments at the atlanto axial joint that are keeping it in place. This is giving it the fracture look. To further confirm a fracture one can see the STIR sequence images and it will show bone edema and fractures better than other images.

Regards,

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Vivek Chail (11 hours later)

I finally got her original MRI that was a bit better quality. What are the circle parts? Those look off to me and possibly a fracture?

Answered by Dr. Vivek Chail (3 hours later)

Brief Answer:
Normal ossification of the odontoid process

Detailed Answer:
Hi,
Thanks for writing in to us.

The odontoid process is not ossified completely in young children and looks like a fracture. The circle is showing ossification of the odontoid process and is normal.

Regards,

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Vivek Chail (13 minutes later)

My apologies. I realized the new images didn’t upload. I just added them. I’m curious as to what that is? It looks like a fragment of some sort?

Answered by Dr. Vivek Chail (15 minutes later)

Brief Answer:
Odontoid process is in fragments and will fuse later

Detailed Answer:
Hi,
Thanks for writing in to us.

You can see the odontoid process is still not completely ossified and is showing fragments that will subsequently fuse at a later age and normal.The ossification centre is bright in the images and the adjacent dark areas are the ligaments keeping it in place. The ligaments are strong and help in stabilising the atlanto axial joint.

Regards,

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Vivek Chail (7 hours later)

Hi, I have provided some attachments. Please review them.

Answered by Dr. Vivek Chail (13 minutes later)

Brief Answer:
Coronal section images are normal

Detailed Answer:
Hi,
Thanks for writing in to us.

The new images are showing coronal section images of the brain at the level of amygdala and hippocampus and is normal. The bilateral inner ears are normal. The midbrain is normal.

The atlantooccipital joint is showing areas of dark ligaments surrounding the bone. The joint is normal,

Regards,

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar