Chiari I Malformation

  • Etiology: abnormality of dorsal induction
  • Imaging: peg shaped cerebellar tonsil > 5 mm below foramen magnum, syrinx in 25%

Radiology Cases of Chiari I Malformation

CT of Chiari I malformation
Sagittal midline 2D reconstruction of CT without contrast of the brain shows the cerebellar tonsils to be herniating > 5 mm beneath the foramen magnum.
Radiograph and MRI of abnormal adolescent idiopathic scoliosis
AP radiograph of the spine (left) shows thoracic scoliosis convex left (levoscoliosis) with a compensatory lumbar scoliosis convex right, thus this is an atypical scoliosis curve for adolescent idiopathic scoliosis. Sagittal T1 MRI without contrast of the cervical spine (above right) shows the tip of the cerebellar tonsils over 10 mm beneath the foramen magnum. Sagittal and axial T2 MRI of the thoracic spine (below right) show a large syrinx in the center of the thoracic spinal cord.