Fig. 2.

Example of the subjective image quality score. From left to right the different scores: score 1 with FBP at 80% reduced dose, score 2 with HIR at 80% reduced dose, score 3 with MIR Soft Tissue at 60% reduced dose and score 4 with HIR at the routine dose level. Note that the kidney stone can be seen in all images. Score 1 was mainly because of excessive noise. Score 2 was also due to substantial noise. Score 3 was given because of smoothening by IR. Score 4 contains some noise, but radiologists are used to some noise and tend to prefer this to extensive smoothening and noise reduction