Table 5.
2D versus 3D intra- and inter-observer reproducibility for peak strain and strain rates
| Intra-observer reproducibility | Inter-observer reproducibility | |||
|---|---|---|---|---|
| Mean absolute bias | ICC (95% CI) | Mean absolute bias | ICC (95% CI) | |
| Circumferential | ||||
| 3D GCS | 1.04 ± 0.83 | 0.88 (0.83–0.92) | 0.94 ± 0.71 | 0.88 (0.79–0.93) |
| 2D GCS | 1.73 ± 1.52* | 0.82 (0.75–0.88) | 2.18 ± 1.77* | 0.66 (0.45–0.79) |
| 3D GCS S’ | 0.09 ± 0.09 | 0.81 (0.73–0.87) | 0.09 ± 0.11 | 0.67 (0.47–0.80) |
| 2D GCS S’ | 0.26 ± 0.34* | 0.44 (0.27–0.59) | 0.26 ± 0.27* | 0.41 (0.14–0.62) |
| 3D GCS E’ | 0.16 ± 0.13 | 0.64 (0.51–0.75) | 0.15 ± 0.16 | 0.72 (0.54–0.84) |
| 2D GCS E’ | 0.49 ± 0.45* | 0.27 (0.08–0.45) | 0.52 ± 0.56* | 0.00 (− 0.27 to 0.29) |
| 3D GCS A’ | 0.04 ± 0.05 | 0.93 (0.90–0.95) | 0.04 ± 0.04 | 0.93 (0.88–0.96) |
| 2D GCS A’ | 0.13 ± 0.11* | 0.74 (0.63–0.82) | 0.17 ± 0.13* | 0.58 (0.35–0.75) |
| Longitudinal | ||||
| 3D GLS | 1.45 ± 1.21 | 0.76 (0.66–0.84) | 1.29 ± 1.12 | 0.74 (0.57–0.85) |
| 2D GLS | 1.91 ± 1.51Ɨ | 0.66 (0.53–0.76) | 1.83 ± 1.31^ | 0.70 (0.52–0.83) |
| 3D GLS S’ | 0.15 ± 0.16 | 0.36 (0.18–0.52) | 0.11 ± 0.11 | 0.62 (0.40–0.77) |
| 2D GLS S’ | 0.20 ± 0.17Ɨ | 0.48 (0.31–0.62) | 0.18 ± 0.14* | 0.62 (0.40–0.77) |
| 3D GLS E’ | 0.20 ± 0.23 | 0.50 (0.33–0.63) | 0.14 ± 0.15 | 0.54 (0.30–0.72) |
| 2D GLS E’ | 0.22 ± 0.19 | 0.53 (0.37–0.66) | 0.23 ± 0.16Ɨ | 0.48 (0.22–0.68) |
| 3D GLS A’ | 0.05 ± 0.06 | 0.80 (0.71–0.86) | 0.05 ± 0.06 | 0.80 (0.66–0.89) |
| 2D GLS A’ | 0.17 ± 0.20* | 0.66 (0.53–0.76) | 0.19 ± 0.18* | 0.54 (0.30–0.72) |
| Radial | ||||
| 3D GRS | 5.32 ± 5.55 | 0.82 (0.75–0.88) | 5.18 ± 5.15 | 0.79 (0.61–0.89) |
| 2D GRS | 7.43 ± 8.36* | 0.74 (0.63–0.82) | 8.38 ± 9.00 | 0.42 (0.16–0.63) |
| 3D GRS S’ | 0.56 ± 0.60 | 0.75 (0.65–0.83) | 0.50 ± 0.49 | 0.73 (0.55–0.85) |
| 2D GRS S’ | 1.02 ± 1.23* | 0.57 (0.24–0.69) | 1.31 ± 1.60* | 0.14 (− 0.12 to 0.39) |
| 3D GRS E’ | 0.71 ± 0.63 | 0.67 (0.54–0.76) | 0.65 ± 0.65 | 0.49 (0.22–0.68) |
| 2D GRS E’ | 1.29 ± 1.24* | 0.42 (0.24–0.57) | 1.65 ± 1.31* | 0.11 (− 0.10 to 0.35) |
| 3D GRS A’ | 0.10 ± 0.12 | 0.85 (0.78–0.90) | 0.10 ± 0.09 | 0.86 (0.76–0.92) |
| 2D GRS A’ | 0.20 ± 0.22* | 0.64 (0.51–0.75) | 0.21 ± 0.17* | 0.70 (0.51–0.83) |
ICC intra-class correlation for single measures
Statistical significance: *denotes paired T test P < 0.001, ^denotes P < 0.01, Ɨ denotes P < 0.05 when comparing the size of bias derived from 2D versus 3D feature tracking on paired t-test