Chiari 1 malformation with focal syrinx

Case contributed by Bruno Di Muzio
Diagnosis certain


Altered sensation down left side of the body.

Patient Data

Age: 30-year-old
Gender: Male

CT Brain (selected images)


Non-contrast Brain CT showing cerebellar tonsillar herniation through the foramen Magnum. Remainder brain (not shown) is unremarkable.

MRI Cx & Tx spine


Technique: Multiplanar, multisequence non-contrast imaging performed. Imaging compared to the previous MRI.

Findings: Stable 7mm descent of the cerebellar tonsils, with minimal crowding of foramen magnum. Fusiform high T2 signal (CSF signal) centrally within the cord at the T4-T5 level with maximum AP dimension of 3.6 mm is unchanged. There is no surrounding T2 hyperintensity or associated mass. Vertebral body alignment, height and marrow signal are preserved. Small right paracentral disc osteophyte complex at C5/6 does not cause significant canal stenosis. Right-sided uncovertebral osteophyte at C5-6 and C6-7 cause minor foraminal narrowing.

Conclusion: Low lying cerebellar tonsils and upper thoracic syringohydromyelia are stable.

Case Discussion

This case is illustrative of the Chiari I malformation, in which there is a caudal descent of the cerebellar tonsil through the foramen magnum. There is also an upper thoracic cord syrinx.

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