Grading system used for the assessment of image quality
| Grade and Definition | Intracranial Findings | Neck Findings | ||
|---|---|---|---|---|
| Circle of Willis | Skull-Base Vessels | Carotids | Vertebral Arteries | |
| 1, nondiagnostic | Obscured | Obscured | Obscured | Obscured |
| 2, poor quality | Poorly visualized | Obscured | Poorly visualized | Obscured |
| 3, acceptable | Clearly seen | Obscured | Clearly seen | Obscured |
| 4, good quality | Clearly seen | Partly obscured | Clearly seen | Partly obscured |
| 5, excellent | Clearly seen | Clearly seen | Clearly seen | Clearly seen |