Table 2. Grading scales for qualitative image analysis.

Score	Subject image noise	Image texture and sharpness	Small-vessel visibility	Diagnostic confidence
1	Unacceptable	Serious blurred delineation	Unacceptable	Unacceptable
2	Above average	Suboptimal blurred delineation	Suboptimal	Suboptimal
3	Average	Moderate blurred delineation	Acceptable	Acceptable
4	Less than average	Minimal blurred delineation	Good	Good
5	Minimal	Hardly any blurring and well-displayed delineation	Excellent	Excellent