Table 3.
Effect sizes (ES) and sample size calculations for rate of atrophy in a-priori and data-driven ROIs (sample sizes are those required for each arm).
| Region | 1.5 T |
3 T |
||||
|---|---|---|---|---|---|---|
| Effect size | Sample size 20% reduction | Sample size 40% reduction | Effect size | Sample size 20% reduction | Sample size 40% reduction | |
| Frontal lobe | 1.11 | 319 | 81 | 1.53 | 170 | 44 |
| Temporal lobe | 1.57 | 161 | 41 | 2.30 | 76 | 20 |
| Frontal and temporal | 1.66 | 145 | 37 | 2.20 | 83 | 22 |
| Lateral ventricles | 1.09 | 332 | 84 | 1.50 | 176 | 45 |
| Whole brain | 1.59 | 157 | 40 | 2.31 | 75 | 20 |
| All regions combined | 1.60 | 154 | 40 | 2.33 | 74 | 20 |
| Data-driven (mean of test ES) | ~1.67 | 155 | 40 | ~2.81 | 55 | 15 |