Table 1.
Reliability of Ki, CBF and BOLD changes.
| CoV (IQR) [%] |
ICC3,1 |
DICE |
|||||
|---|---|---|---|---|---|---|---|
| FEF | IPS | OCC | FEF | IPS | OCC | Whole brain | |
| Ki | |||||||
| Rest | 5.4 (4.2) | 4.6 (2.6) | 5.0 (4.0) | 0.88 | 0.89 | 0.87 | - |
| Easy vs Rest | 26.1 (43.1) | 27.9 (43.1) | 29.9 (52.2) | 0.50 | 0.52 | 0.33 | 0.53 |
| Hard vs Rest | 21.0 (34.8) | 17.8 (16.2) | 13.6 (21.3) | 0.65 | 0.76 | 0.65 | 0.61 |
| CBF | |||||||
| Rest | 10.1 (10.4) | 6.4 (10.5) | 5.3 (7.8) | 0.39 | 0.69 | 0.76 | - |
| Easy vs Rest | 38.7 (62.0) | 32.4 (28.3) | 24.9 (39.3) | 0.51 | 0.43 | 0.67 | 0.68 |
| Hard vs Rest | 15.0 (31.8) | 25.1 (43.2) | 17.5 (24.5) | 0.67 | 0.48 | 0.72 | 0.73 |
| BOLD | |||||||
| Easy vs Rest | 31.7 (31.2) | 20.5 (37.3) | 28.9 (49.8) | 0.40 | 0.45 | 0.23 | 0.81 |
| Hard vs Rest | 16.4 (19.5) | 21.1 (24.2) | 24.5 (20.4) | 0.41 | 0.13 | 0.09 | 0.78 |
| Control vs Rest | 22.3 (40.9) | 38.9 (49.1) | 24.5 (51.4) | 0.72 | 0.44 | 0.13 | 0.78 |
| Easy vs Control | 61.4 (80.0) | 43.4 (54.8) | 40.2 (141.9) | –0.06 | 0.46 | 0.55 | 0.35 |
| Hard vs Control | 34.0 (63.7) | 33.8 (104.4) | 49.4 (51.7) | 0.12 | –0.08 | 0.12 | 0.70 |
Commonly used metrics for test-retest reliability were estimated, namely median within-subject coefficient of variation (CoV), and intraclass correlation (ICC) for each ROI and each condition. Additionally, whole-brain DICE coefficient was calculated. At resting state, Ki exhibited the highest reliability. During task performance, reliability dropped but was comparable between Ki and CBF. With BOLD imaging the best performance was achieved with the DICE coefficient, i.e. the qualitative spatial overlap of task effects between measurements.FEF: frontal eye field, IPS: intraparietal sulcus, OCC: occipital cortex.