Table 3.
Features of Chiari II malformation present on MR images in children with open or closed spinal dysraphism or without spinal dysraphism
| Feature | Spinal dysraphism | No spinal dysraphism | |
|---|---|---|---|
| Open | Closed | ||
| (%a) | (%a) | (%a) | |
| Sagittal plane (n = 207) | |||
| Downward herniation cerebellum | 83 | 16 | 4 |
| Downward herniation vermis | 74 | 10 | 2 |
| Downward herniation tonsil | 75 | 14 | 1 |
| Upward herniation cerebellum | 33 | 2 | 0 |
| Downward displacement medulla | 68 | 8 | 0 |
| Downward displacement pons | 61 | 2 | 0 |
| Downward displacement fourth ventricle | 64 | 2 | 0 |
| Medullary kinking | 40 | 6 | 0 |
| Flattened pons | 75 | 2 | 5 |
| Abnormal width fourth ventricle | 74 | 2 | 0 |
| Hypoplastic tentorium | 67 | 0 | 0 |
| Abnormal course straight sinus | 71 | 0 | 7 |
| Beaked tectum | 72 | 0 | 0 |
| Enlarged massa intermedia | 36 | 35 | 43 |
| Stenogyria | 32 | 2 | 0 |
| Axial plane (n = 174) | |||
| Cerebellum in cervical spinal canal | 47 | 7 | 3 |
| Vermis in cervical spinal canal | 15 | 0 | 0 |
| Tonsil in cervical spinal canal | 24 | 0 | 0 |
| Cerebellum wrapped around brainstem | 50 | 0 | 0 |
| Abnormal fissural pattern of cerebellum | 68 | 43 | 26 |
| Small fourth ventricle | 68 | 3 | 0 |
| Enlarged fourth ventricle | 8 | 0 | 0 |
| Beaked tectum | 56 | 0 | 0 |
| Enlarged massa intermedia | 23 | 0 | 3 |
| Gyral interdigitation | 56 | 7 | 3 |
| Stenogyria | 21 | 0 | 0 |
| Coronal plane (n = 153) | |||
| Downward herniation cerebellum | 67 | 6 | 0 |
| Downward herniation vermis | 65 | 6 | 0 |
| Downward herniation tonsil | 20 | 0 | 0 |
| Upward herniation cerebellum | 38 | 0 | 0 |
| Indentation | 25 | 0 | 0 |
| Hypoplastic tentorium | 35 | 0 | 0 |
| Gyral interdigitation | 38 | 12 | 0 |
aThe numbers represent percentages of present ratings based on the overall ratings of three observers