Table 2.
Noise and CNR at different dose levels with FBP, HIR and MIR
| Noise (aorta) | Noise (fat) | CNR | |
|---|---|---|---|
| Routine dose | |||
| FBP | 37.5 (28.1–42.8) | 30.2 (25.4–52.0) | 4.8 (3.0–5.5) |
| HIR | 18.4 (15.0–22.2)a | 18.2 (14.6–23.3)a | 8.3 (6.7–10.1)a |
| MIR | 11.4 (9.5–12.5)a | 11.5 (9.8–15.2)a | 13.0 (10.7–15.9)a |
| 45% reduced dose | |||
| FBP | 46.6 (38.9–58.4)a | 39.3 (31.6–78.9)a | 3.3 (2.1–4.5)a |
| HIR | 23.2 (20.5–26.5)a | 23.5 (17.5–27.8)a | 6.7 (5.5–8.1)a |
| MIR | 12.3 (11.3–14.4)a | 13.5 (10.7–17.2)a | 11.4 (9.0–13.7)a |
| 60% reduced dose | |||
| FBP | 60.2 (47.8–81.4)a | 50.8 (42.5–94.6)a | 2.5 (1.7–3.5)a |
| HIR | 26.4 (22.9–31.8)a | 28.1 (21.4–34.7)a | 5.5 (4.4–6.8)a |
| MIR | 13.7 (12.2–16.5)a | 13.9 (12.7–17.2)a | 11.4 (8.9–12.4)a |
| 75% reduced dose | |||
| FBP | 80.0 (61.4–108.5)a | 62.8 (47.5–142.6)a | 2.3 (1.2–2.7)a |
| HIR | 32.6 (28.5–37.8) | 30.4 (24.7–39.6) | 4.7 (3.7–5.7) |
| MIR | 16.4 (14.1–19.7)a | 15.1 (13.8–19.1)a | 9.2 (7.9–11.3)a |
Values are presented as median (interquartile range)
aStatistically significant difference compared to FBP at routine dose with a Bonferroni corrected p value of 0.017
CNR contrast-to-noise ratio, FBP filtered back projection, HIR hybrid iterative reconstruction, MIR model-based iterative reconstruction