Chiari 0

 Crowded foramen magnum, arachnoid adhesions, 4th ventricular arachnoid veil

image Cisterna magna impacted by tonsils (“tight cisterna magna”)

Clinical Issues

• Most common symptoms
image Chiari-like headache

image Neck or back pain

image Scoliosis

• Carefully selected patients benefit from posterior fossa decompression + duraplasty
image Syrinx frequently improves or resolves without syrinx drainage catheter placement

Diagnostic Checklist

• CM 0 rare; diagnosis made only after other syrinx etiologies excluded

• Existence as separate diagnosis is controversial

(Left) Sagittal T2WI MR reveals syringohydromyelia image of the midcervical spinal cord in conjunction with low obex image position. The cerebellar tonsils are rounded without abnormal caudal descent.

(Right) Sagittal T1WI MR confirms midcervical syringohydromyelia image. No cerebellar tonsillar ectopia is present to explain syringohydromyelia, although the obex image is low, prompting clinical consideration of Chiari 0 malformation.

(Left) Sagittal 3D FIESTA image (from a cine MR clip) demonstrates moderate cervical syringohydromyelia image and low obex image without abnormal cerebellar tonsillar ectopia. In this patient, the cine MR clip did not confirm suspected aberrant CSF flow at the foramen magnum.

(Right) Axial T2WI MR in a patient clinically suspected to have Chiari 0 malformation shows moderate cervical syringohydromyelia image.



• Chiari 0 (CM 0)


• Chiari type 0


• Syringomyelia without cerebellar tonsillar herniation

• Headache, typical Chiari 1 malformation (CM1) symptoms


General Features

Oct 5, 2016 | Posted by in NEUROLOGICAL IMAGING | Comments Off on Chiari 0

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