Chiari I malformation | Figure 1
CincyKidsRad
Cincinnati Children's Radiology
Chiari I malformation
Sagittal T2 (image 1) and T1 (image 2) weighted MRI show a Chiari I malformation (arrow) with elongation or a 'peg' shape of the cerebellar tonsils descending well below the foramen magnum. Patients may describe occipital or cervical headaches that worsen with coughing or straining. A Chiari I malformation is diagnosed when the cerebellar tonsils extend more than 5 mm below the foramen magnum.