Mean CNR and SD of ON and IRM for each combination of protocol and reconstruction techniquea
| Dose Protocol | Reconstruction Technique | ON | IRM | Score Bone Kernel | Score Std Kernel |
|---|---|---|---|---|---|
| CNR (SD) | CNR (SD) | ||||
| Emergency protocol head | ASIR-50 | 2.75 (0.62) | 1.82 (0.26) | 4.0 | |
| Reference dose protocol | FBP | 3.80 (2.07) | 2.39 (1.22) | 3.0 | 4.0 |
| ASIR-50 | 4.28 (2.04) | 2.71 (1.24) | 3.0 | 4.0 | |
| ASIR-100 | 4.37 (1.39) | 2.99 (1.01) | 3.0 | 4.0 | |
| MBIR | 5.68 (0.17) | 3.60 (0.54) | 5.0 | ||
| Low-dose protocol I | FBP | 1.57 (1.07)b | 1.11 (0.79) | 2.0 | 3.0 |
| ASIR-50 | 2.15 (1.27) | 1.22 (0.81) | 2.0 | 3.0 | |
| ASIR-100 | 2.49 (0.98) | 1.65 (0.59) | 2.0 | 3.0 | |
| MBIR | 4.12 (0.85) | 3.05 (0.46) | 4.0 | ||
| Low-dose protocol II | FBP | 1.05 (0.75)b | 0.74 (0.46)b | 1.0 | 2.0 |
| ASIR-50 | 1.41 (0.94)b | 0.91 (0.43) | 1.0 | 2.0 | |
| ASIR-100 | 2.16 (1.15) | 1.34 (0.40) | 1.0 | 3.0 | |
| MBIR | 4.11 (0.66) | 2.81 (0.77) | 4.0 | ||
| Low-dose protocol III | FBP | 0.63 (0.44)b | 0.23 (0.30)b | 1.0 | 1.0 |
| ASIR-50 | 0.87 (0.57)b | 0.50 (0.44b | 1.0 | 1.0 | |
| ASIR-100 | 1.29 (0.65)b | 0.92 (0.60) | 1.0 | 1.0 | |
| MBIR | 3.08 (0.63) | 2.32 (0.44) | 2.0 | ||
| Low-dose protocol IV | FBP | 0.44 (0.36)b | 0.10 (0.16)b | 1.0 | 1.0 |
| ASIR-50 | 0.52 (0.57)b | 0.31 (0.34)b | 1.0 | 1.0 | |
| ASIR-100 | 0.93 (0.63)b | 0.62 (0.56)b | 1.0 | 1.0 | |
| MBIR | 2.62 (0.52) | 3.14 (2.71) | 2.0 |
Note:—Std indicates standard.
↵a Subjective scores are given separately for images with a bone and standard kernel: 1 indicates very poor/not sufficient; 2, suboptimal but sufficient; 3, average = equal to reference; 4, above average; and 5, excellent.
↵b Statistically significant difference compared with the reference dose protocol with FBP (P < .05).