Figure 2.

Qualitative assessment of image quality and vascular characteristics. Image quality was evaluated on a 4-point scale (1: non-diagnostic; 2: poor definition such that only gross features such as overall patency are evaluable; 3: good definition such that pathology can be confidently visualized or excluded; 4: excellent definition such that detailed anatomy is clearly visualized with sharp borders). A 4-point scale was also used to assess confidence in vessel tortuosity, calcific burden, calcific morphology, and atheroma (1: no confidence, 2: mild confidence, 3: moderate confidence, 4: strong confidence).