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Abnormalities on direct-access CT in patients with chronic headache that were likely to be causative of the presenting symptoms (n = 60)
| Abnormality | n | Rate, % |
|---|---|---|
| Brain tumour | 22 | 0.5 |
| Chiari I malformation | 18 | 0.4 |
| Arachnoid cyst | 12 | 0.2 |
| Cerebral aneurysm | 5 | 0.1 |
| Colloid cyst | 2 | 0.04 |
| AVM | 1 | 0.02 |
AVM = Arteriovenous malformation.
