Chiari 1 malformation with focal syrinx

Case contributed by Frank Gaillard
Diagnosis certain

Patient Data

Age: 30 years
Gender: Female
  • Note: This case has been tagged as "legacy" as it no longer meets image preparation and/or other case publication guidelines.

MRI brain



Measurement of Chiari 1

Annotated image

Diagram and annotated image of how to measure tonsilar descent. A line (dotted blue) is drawn on the midline sagittal plane across the inner margins foramen magnum (ophisthion to basion), and measuring the inferior most part of the tonsils (green arrows). The tonsils normally protrude through foramen magnum by no more than 5 mm.

MRI cervical cord


MRI of the cervical spine with contrast demonstrates a focal cystic dilatation in the center of the cord behind C2. There is some additional high T2 signal extending inferiorly. There is no solid component or evidence of contrast enhancement. 

Post-op MRI


Posterior fossa decompressive craniectomy and resection of the posterior arch of C1 is again demonstrated. There has been reduction in the size of the focal syrinx at the level of C2. 

Case Discussion

This case illustrates a Chiari 1 malformation complicated by a focal syrinx in the upper cervical cord. The patient was treated with a posterior fossa / C1 decompression which resulted in both radiological and symptomatic improvement. 

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