TABLE 2:

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