Table 2. Changes in the Proportion of High-Dose Studies (Proportion Over Benchmark) After Interventions by Anatomical Area for Effective Dose, Organ Dose, and CTDIvola.
| Variable | Proportion Over Benchmark Before Intervention | After Intervention | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Audit Alone | Multicomponent Intervention | ||||||||
| Proportion Over Benchmark | Change in Proportion Over Benchmark Absolute (%) | OR (95% CI) | P Value | Proportion Over Benchmark | Change in Proportion Over Benchmark Absolute (%) | OR (95% CI) | P Value | ||
| Effective dose | |||||||||
| Abdomen | 24.7 | 24.7 | 0.0 (0) | 1.00 (0.96-1.05) | .86 | 22.2 | −2.4 (−10) | 0.82 (0.77-0.88) | <.001 |
| Chest | 26 | 25.5 | −0.5 (−2) | 0.96 (0.90-0.98) | .10 | 24.9 | −1.1 (−4) | 0.92 (0.86-0.99) | .03 |
| Combined abdomen and chest | 26.7 | 23 | −3.7 (−14) | 0.73 (0.66-0.81) | <.001 | 18.8 | −7.9 (−30) | 0.49 (0.41-0.59) | <.001 |
| Head | 26.2 | 26 | −0.2 (−1) | 0.99 (0.90-0.97) | .50 | 21.8 | −4.4 (−17) | 0.71 (0.66-0.76) | <.001 |
| Organ doses | |||||||||
| Abdomenb | 24.9 | 22.6 | −2.3 (−9) | 0.84 (0.81-0.88) | <.001 | 18.0 | −6.9 (−28) | 0.59 (0.55-0.63) | <.001 |
| Chestc | 25.6 | 22.5 | −3.1 (−12) | 0.80 (0.77-0.84) | <.001 | 19.7 | −6.0 (−23) | 0.65 (0.60-0.69) | <.001 |
| Combined abdomen and chestc | 30.2 | 20.8 | −9.4 (−31) | 0.48 (0.43-0.53) | <.001 | 13.3 | −17.2 (−57) | 0.23 (0.19-0.27) | <.001 |
| Combined abdomen and chestb | 28.3 | 13.6 | −14.7 (−52) | 0.29 (0.26-0.33) | <.001 | 12.0 | −16.3 (−58) | 0.25 (0.21-0.30) | <.001 |
| Headd | 27.5 | 25.6 | −1.9 (−7) | 0.88 (0.85-0.92) | <.001 | 21.0 | −6.5 (−24) | 0.62 (0.59-0.67) | <.001 |
| CTDIvol | |||||||||
| Abdomen | 24.5 | 24.9 | 0.4 (2) | 1.04 (0.99-1.09) | .08 | 24.1 | −0.4 (−2) | 0.96 (0.89-1.03) | .25 |
| Chest | 26 | 25.8 | −0.2 (−1) | 0.98 (0.94-1.03) | .44 | 24.1 | −2.0 (−8) | 0.85 (0.79-0.92) | <.001 |
| Combined abdomen and chest | 23.6 | 22.7 | −0.9 (−4) | 0.90 (0.79-1.03) | .12 | 19.9 | −3.7 (−16) | 0.64 (0.51-0.80) | <.001 |
| Head | 24.4 | 25.0 | 0.6 (2) | 1.07 (1.02-1.13) | .007 | 17.9 | −6.5 (−27) | 0.44 (0.40-0.48) | <.001 |
Abbreviations: CTDIvol, volume computed tomographic dose index; OR, odds ratio.
a
Results are after audit alone and after complex intervention relative to before intervention adjusting for temporal trends and patient and facility characteristics by anatomical area.
b
Colon organ doses.
c
Lung organ doses.
d
Brain organ doses.