| Specific Anatomic Region | Circle of Willis |
| Application | R/O aneurysm |
| Author | Katz DA et al. |
| Reference Source | Radiology 1995; 195:445-449 |
| Scanner Used | Siemens Somatom Plus-S |
| Injection Rate | 3ml/sec |
| Contrast Volume and Type | 90ml of Omnipaque-300 |
| Area Scanned | Entire brain (if possible) |
| Scan Delay | Test-dose timing (usually 15-25sec) |
| Length of Spiral (time) | 40sec |
| Slice Thickness | 1mm |
| Table Speed/Pitch | 1.3mm/sec with a pitch of 1.3 |
| Reconstruction Interval | 0.5mm |
| 3D Technique Used | None used |
| Comment: Spiral compared favorably with MRI. We like to use 3D imaging with volume rendering when looking at the aneurysm and its vascular anatomy. By using fly-around virtual techniques the neck of the aneurysm is best seen. | |