Table 1:

Subjective image quality rating (1 = worst, 5 = best) for brain structures and intracranial hemorrhage for filtered back-projection and 5 strengths (S1–S5) of sinogram-affirmed iterative reconstruction technique

Image Reconstruction TechniqueRating Brain StructuresRating Intracranial Hemorrhage
340 mAs260 mAs340 mAs260 mAs
κκκκ
FBP2.8 ± 0.40.712.0 ± 0.80.592.5 ± 0.70.92.1 ± 0.80.67
S13.5 ± 0.6a0.712.9 ± 0.6a0.483.15 ± 0.8c0.852.8 ± 0.8a,c0.9
S24.4 ± 0.60.773.7 ± 0.7a0.513.8 ± 0.7c0.823.4 ± 0.7c0.75
S34.5 ± 0.5c0.474.7 ± 0.5c0.624.39 ± 0.7c0.804.0 ± 0.7c0.72
S43.2 ± 0.7a,c0.863.4 ± 1.0a,c0.554.65 ± 0.6c0.814.65 ± 0.5c0.61
S52.0 ± 0.7b,c0.642.5 ± 0.9b,c0.374.44 ± 0.7c0.814.68 ± 0.6c0.55
  • Note:a P > .05 when compared with standard FBP at 340 mAs;

  • b P > .05 when compared with FBP at 260 mAs;

  • c P > 0.1 when compared with the same image reconstruction technique at different tube current–time product.

  • Interobserver agreement (slight [κ < 0.3], moderate [κ = 0.3–0.7], good agreement [κ > 0.7]).