Table 2.
Reflection magnitude and accuracy of wave separation for different flow waveforms
| PCMRI | RepFlow | Kips | Triangle | DopEnv | DopMean | PeakU | |
|---|---|---|---|---|---|---|---|
| Group 1 (n = 45) | |||||||
| RM (–) | 0.52 ± 0.13 | 0.52 ± 0.13 | 0.51 ± 0.12c | 0.51 ± 0.12c | 0.50 ± 0.13a | 0.50 ± 0.12a | 0.51 ± 0.13 |
| RM Error (%) | – | 0.4 ± 4.2 | − 2.6 ± 4.8e | − 2.3 ± 7.9f | − 4.9 ± 5.9d | − 4.2 ± 5.8d | − 1.8 ± 5.5 |
| |RM Error| (%) | – | 3.3 ± 2.5 | 4.3 ± 3.3 | 6.1 ± 5.4e | 5.8 ± 4.9e | 5.6 ± 4.4f | 4.0 ± 4.1 |
| Tr (ms) | 268 ± 54 | 271 ± 55 | 267 ± 54 | 249 ± 51a | 271 ± 56 | 279 ± 58a | 268 ± 58 |
| Tr Error (%) | – | 1.1 ± 2.7 | − 0.4 ± 4.5 | − 7.2 ± 3.5d | 0.9 ± 3.8 | 4.0 ± 4.2e | − 0.4 ± 3.5 |
| |Tr Error| (%) | – | 2.1 ± 2.0 | 3.6 ± 2.7f | 7.2 ± 3.5d | 3.1 ± 2.2 | 4.8 ± 3.3d | 2.9 ± 2.0 |
| RMSE (Af,b, mm2) | – | 2.8 ± 1.6 | 5.7 ± 2.5d | 6.6 ± 3.3d | 4.9 ± 3.0d | 5.6 ± 3.3d | 4.1 ± 2.3e |
| RMSE (Pf,b, mmHg)g | – | 0.8 ± 0.5 | 1.5 ± 0.6d | 1.6 ± 0.7d | 1.2 ± 0.7d | 1.5 ± 0.9d | 1.1 ± 0.6 |
| Group 2 (n = 79) | |||||||
| RM (–) | 0.52 ± 0.09 | 0.50 ± 0.09 | 0.48 ± 0.08a | 0.47 ± 0.08a | 0.48 ± 0.08a | 0.52 ± 0.10 | 0.49 ± 0.09a |
| RM Error (%) | – | − 2.9 ± 6.1 | − 7.0 ± 6.6e | − 8.8 ± 9.4d | − 6.5 ± 9.6e | 1.4 ± 10.6e | − 5.1 ± 9.6 |
| |RM Error| (%) | – | 5.1 ± 4.5 | 7.8 ± 5.7e | 10.9 ± 6.9d | 9.1 ± 7.1d | 7.8 ± 7.2e | 8.2 ± 7.1e |
| Tr (ms) | 274 ± 61 | 278 ± 61 | 274 ± 64 | 251 ± 58a | 282 ± 63a | 291 ± 65a | 273 ± 60 |
| Tr Error (%) | – | 1.7 ± 3.3 | − 0.0 ± 5.5 | − 8.6 ± 3.6d | 3.1 ± 6.0 | 6.5 ± 6.6d | − 0.2 ± 5.8f |
| |Tr Error| (%) | – | 3.1 ± 2.1 | 4.1 ± 3.6 | 8.6 ± 3.6d | 5.3 ± 4.2d | 7.7 ± 5.1d | 4.3 ± 3.8 |
| RMSE (Af,b, mm2) | – | 5.1 ± 3.2 | 8.5 ± 4.1d | 8.4 ± 3.3d | 8.6 ± 5.8d | 10.3 ± 7.5d | 7.0 ± 4.7e |
| RMSE (Pf,b, mmHg)g | – | 1.0 ± 0.6 | 1.7 ± 0.9d | 1.7 ± 0.8d | 1.7 ± 1.2d | 2.1 ± 1.5d | 1.4 ± 1.0e |
| Group 3 (n = 29) | |||||||
| RM (–) | 0.56 ± 0.10 | 0.53 ± 0.09c | 0.51 ± 0.09a | 0.49 ± 0.08a | 0.48 ± 0.08a | 0.52 ± 0.09a | 0.48 ± 0.07a |
| RM Error (%) | – | − 4.5 ± 6.5 | − 8.3 ± 6.2 | − 11.6 ± 10.4d | − 13.0 ± 8.6d | − 5.7 ± 6.7 | − 13.8 ± 8.2d |
| |RM Error| (%) | – | 6.2 ± 4.8 | 9.1 ± 4.9 | 13.4 ± 7.8d | 13.9 ± 7.0d | 6.7 ± 5.7 | 14.1 ± 7.7d |
| Tr (ms) | 288 ± 47 | 286 ± 49 | 284 ± 49 | 265 ± 44a | 294 ± 56 | 305 ± 54a | 286 ± 51 |
| Tr Error (%) | – | − 0.6 ± 3.5 | − 1.2 ± 4.9 | − 7.8 ± 3.1d | 1.9 ± 6.6 | 6.0 ± 6.2d | − 0.7 ± 4.5 |
| |Tr Error| (%) | – | 2.9 ± 2.1 | 3.8 ± 3.3 | 7.8 ± 3.1d | 5.3 ± 4.3e | 7.2 ± 4.7d | 3.5 ± 2.8 |
| RMSE (Af,b, mm2) | – | 5.5 ± 2.9 | 8.2 ± 4.4f | 9.0 ± 3.0e | 10.8 ± 5.0d | 12.9 ± 8.4d | 10.5 ± 7.2d |
| RMSE (Pf,b, mmHg)g | – | 1.3 ± 0.7 | 1.6 ± 0.6 | 2.1 ± 0.8e | 2.3 ± 1.3d | 2.8 ± 2.1d | 2.0 ± 1.0e |
ap ≤ 0.001, bp ≤ 0.01, cp < 0.05, compared with PCMRI; dp ≤ 0.001, ep ≤ 0.01, fp < 0.05, compared with RepFlow; gn = 34 (Group 1), n = 70 (Group 2), n = 25 (Group 3) due to missing blood pressure data. PCMRI, subject-specific flow waveform from phase contrast magnetic resonance imaging; RepFlow, representative flow waveform derived from PCMRI in Group 1 in the present study; Kips, representative flow waveform from ultrasound in adults reported by Kips et al. [28]; Triangle, triangular flow waveform as in Westerhof et al. [27] with peak at 25% of systolic duration; DopEnv, using flow waveform obtained by tracing the envelope of the virtual Doppler ultrasound; DopMean, using flow waveform obtained as the intensity-weighted spectral average from the virtual Doppler ultrasound; PeakU, flow waveform obtained as the instantaneous peak velocity within the lumen. Vertical bars (as in |RM Error|) refer to absolute values. RM reflection magnitude, RMSE root mean square error for forward or backward waveforms of area (Af,b) and pressure (Pf,b), Tr return time of the reflected wave.