Summary of CTA and DSA findings
| DSA Findings | Subtraction CTA | Conventional CTA | Total | ||||
|---|---|---|---|---|---|---|---|
| Positive | Negative | NA | Positive | Negative | NA | ||
| Residual neck | |||||||
| Positive | 4 | 0 | 0 | 1 | 0 | 3 | 4 |
| Negative | 0 | 15 | 1 | 0 | 4 | 12 | 16 |
| Parent or neighboring artery steno-occlusive change | |||||||
| Positive | 1 | 0 | 0 | 0 | 0 | 1 | 1 |
| Negative | 1 | 18 | 0 | 3 | 6 | 10 | 19 |
Note:—NA indicates not applicable for diagnosis due to clip-induced artifact or inappropriate subtraction.