Fig. 4: Stacked bar graphs display the distribution of quality scores.

Eight radiologists independently rated Real, BIS, and DLS 1-mm CT using a five-point Likert scale (1 = unacceptable, 2 = poor, 3 = acceptable, 4 = good, 5 = excellent). In the Likert scale, scores of ‘unacceptable’ and ‘poor’ are defined as nondiagnostic (displayed in varying shades of red); scores of ‘acceptable’, ‘good’ and ‘excellent’ are defined as diagnostic (displayed in varying shades of green). BIS indicates bicubic interpolation synthetic, DLS deep learning synthetic, CN China, US United States.