Chiari I Malformation

Clinical History:
This is a 21-year-old male with recent headaches. The headaches are described as intermittent throbbing and result in numbness, tingling, and blurred vision.

Chiari I Malformation

MR Technique:
3.0 T scanner (Siemens Verio) using an 15-channel head coil. Image 1: sagittal T1-weighted image (TR/TE 440/2.5 ms, scan time 2 min 28 sec, slice thickness 4 mm); Image 2: axial T2-weighted image (TR/TE 6000/96 ms, scan time 1 min 26 sec, slice thickness 4 mm); Image 3: coronal T2-weighted image (TR/TE 6350/96 ms, scan time 1 min 30 sec, thickness 4 mm).

Imaging Findings:
The cerebellar tonsils project over 1 cm below the inferior margin of the foramen magnum, consistent with Chiari I malformation. There is expected crowding within the foramen magnum. The remainder of the posterior fossa is normal. No supratentorial abnormalities are seen and the ventricles are normally sized.